MIME message fixtures with real threading headers, valid multipart boundaries, matching transfer encodings and a raw message that actually parses.
Generated test data for fixtures and development
Each record describes one root message: identification headers, mailboxes, the unfolded header block, the part tree and attachment metadata. Bodies are summarised as bodyPreview — fetch /raw for the complete message text.
| Parameter | Type | Default & allowed | Description |
|---|---|---|---|
structure | enum | default: alternative allowed: plain | alternative | mixed | nested example: nested | Part tree: 'plain' = one text/plain entity; 'alternative' = multipart/alternative with text/plain then text/html; 'mixed' = multipart/mixed with a text/plain part plus attachment parts; 'nested' = multipart/mixed wrapping a multipart/alternative plus attachment parts. |
attachments | int | default: 0 allowed: 0 – 3 example: 2 | Exact number of attachment parts. Requires structure=mixed or structure=nested; anything above 0 with 'plain' or 'alternative' is a 400. |
encoding | enum | default: quotedPrintable allowed: 7bit | quotedPrintable | base64 example: base64 | Content-Transfer-Encoding for the text parts; 'quotedPrintable' emits the literal token 'quoted-printable'. Binary attachment parts stay base64 regardless. |
unicode | boolean | default: false example: true | Use display names and a subject that contain non-ASCII characters, forcing RFC 2047 'B' encoded-words in From/To/Cc/Subject. Body text and local parts stay US-ASCII either way. |
from | date | example: 2026-01-01 | Earliest message date, inclusive. YYYY-MM-DD (= midnight UTC) or a full ISO 8601 timestamp. With only from, to resolves exactly 30 days later; with neither bound, the window is the 30 days up to today at UTC midnight. |
to | date | example: 2026-03-31 | Latest message date, inclusive. YYYY-MM-DD means midnight UTC — pass a timestamp to cover that whole day. Must be ≥ from, and the window must contain at least one whole second, because an RFC 5322 Date has second precision. With only to, from resolves exactly 30 days earlier. |
structure enum Part tree: 'plain' = one text/plain entity; 'alternative' = multipart/alternative with text/plain then text/html; 'mixed' = multipart/mixed with a text/plain part plus attachment parts; 'nested' = multipart/mixed wrapping a multipart/alternative plus attachment parts.
attachments int Exact number of attachment parts. Requires structure=mixed or structure=nested; anything above 0 with 'plain' or 'alternative' is a 400.
encoding enum Content-Transfer-Encoding for the text parts; 'quotedPrintable' emits the literal token 'quoted-printable'. Binary attachment parts stay base64 regardless.
unicode boolean Use display names and a subject that contain non-ASCII characters, forcing RFC 2047 'B' encoded-words in From/To/Cc/Subject. Body text and local parts stay US-ASCII either way.
from date Earliest message date, inclusive. YYYY-MM-DD (= midnight UTC) or a full ISO 8601 timestamp. With only from, to resolves exactly 30 days later; with neither bound, the window is the 30 days up to today at UTC midnight.
to date Latest message date, inclusive. YYYY-MM-DD means midnight UTC — pass a timestamp to cover that whole day. Must be ≥ from, and the window must contain at least one whole second, because an RFC 5322 Date has second precision. With only to, from resolves exactly 30 days earlier.
| Parameter | Type | Default & allowed | Description |
|---|---|---|---|
count | int | default: 10 allowed: 1 – 100 example: 3 | How many records to generate (1–100). |
seed | int | example: 42 | Deterministic output: the same seed always returns the same records. Omit for random (the used seed is echoed in meta.seed). |
fields | list | example: messageId,inReplyTo | Return only these fields (comma-separated). Mutually exclusive with 'exclude'. |
exclude | list | example: bodyPreview | Return all fields except these (comma-separated). |
format | enum | default: json allowed: json | ndjson | csv example: csv | Response format: json envelope, ndjson (one record per line) or csv. |
pretty | boolean | default: false example: true | Pretty-print the JSON response. |
unwrap | boolean | default: false example: true | Drop the envelope: return the raw array/object without data/meta wrapper. |
count int How many records to generate (1–100).
seed int Deterministic output: the same seed always returns the same records. Omit for random (the used seed is echoed in meta.seed).
fields list Return only these fields (comma-separated). Mutually exclusive with 'exclude'.
exclude list Return all fields except these (comma-separated).
format enum Response format: json envelope, ndjson (one record per line) or csv.
pretty boolean Pretty-print the JSON response.
unwrap boolean Drop the envelope: return the raw array/object without data/meta wrapper.
| Field | Type | Description | Example |
|---|---|---|---|
messageId | string | Message-ID in <local@domain> form; the domain is always an RFC 2606 reserved name. | <20260721T120311.9c1d4a7f0b23@northwind.test> |
inReplyTo nullable | string | Parent's Message-ID, or null. Always null here — the list route returns root messages; /thread builds the chain. | null |
references | string[] | Ordered ancestor Message-IDs, root first, ending with the direct parent. Always empty here (root messages). | [] |
from | object | Sender mailbox: { name, address }. | {"name":"Ada Lovelace","address":"ada.lovelace@northwind.test"} |
to | object[] | One or two primary recipient mailboxes (usually one), always distinct — the same mailbox is never listed twice. | [{"name":"Ada Lovelace","address":"ada.lovelace@northwind.test"}] |
cc | object[] | Zero or one copied mailbox; empty when no Cc header is emitted. | [] |
subject | string | Decoded subject. With unicode=true the wire form in headers.Subject is RFC 2047 encoded-words instead. | Q3 roadmap review: agenda and open questions |
date | string (ISO 8601) | The same instant as the Date header, in UTC at second precision — the RFC 5322 form lives in headers.Date. | 2026-07-21T12:03:11Z |
headers | object | Top-level header values in unfolded wire form, keyed by canonical field name (Date, From, To, Cc, Subject, Message-ID, MIME-Version, Content-Type…). | {"Date":"Tue, 21 Jul 2026 14:03:11 +0200","From":"\"Ada Lovelace\" <ada.lovelace@northwind.test>","To":"\"Grace Hopper\" <grace.hopper@example.net>","Subject":"Q3 roadmap review: agenda and open questions","Message-ID":"<20260721T120311.9c1d4a7f0b23@northwind.test>","MIME-Version":"1.0","Content-Type":"multipart/alternative; boundary=\"----=_Part_4f2a91c0_8b3d17e6\""} |
structure | object | Part tree — shape only: contentType, boundary and nested parts for containers; contentType, charset, contentTransferEncoding, decoded sizeBytes and disposition for leaves. Attachment filenames and Content-IDs live in `attachments`. | {"contentType":"multipart/alternative","boundary":"----=_Part_4f2a91c0_8b3d17e6","parts":[{"contentType":"text/plain","charset":"utf-8","contentTransferEncoding":"quoted-printable","sizeBytes":412},{"contentType":"text/html","charset":"utf-8","contentTransferEncoding":"quoted-printable","sizeBytes":733}]} |
attachments | object[] | One entry per attachment part, in part order: filename, contentType, decoded sizeBytes, contentTransferEncoding and contentId. | [{"filename":"q3-report.pdf","contentType":"application/pdf","sizeBytes":1843,"contentTransferEncoding":"base64","contentId":"<9f0c2a71b4d8@northwind.test>"}] |
bodyPreview | string | First 80 characters of the decoded text/plain part with whitespace collapsed, truncated with an ellipsis. | Hi Grace, Thanks for the quick turnaround on the last batch - the totals line… |
messageId string Message-ID in <local@domain> form; the domain is always an RFC 2606 reserved name.
example: <20260721T120311.9c1d4a7f0b23@northwind.test>
inReplyTo string nullable Parent's Message-ID, or null. Always null here — the list route returns root messages; /thread builds the chain.
example: null
references string[] Ordered ancestor Message-IDs, root first, ending with the direct parent. Always empty here (root messages).
example: []
from object Sender mailbox: { name, address }.
example: {"name":"Ada Lovelace","address":"ada.lovelace@northwind.test"}
to object[] One or two primary recipient mailboxes (usually one), always distinct — the same mailbox is never listed twice.
example: [{"name":"Ada Lovelace","address":"ada.lovelace@northwind.test"}]
cc object[] Zero or one copied mailbox; empty when no Cc header is emitted.
example: []
subject string Decoded subject. With unicode=true the wire form in headers.Subject is RFC 2047 encoded-words instead.
example: Q3 roadmap review: agenda and open questions
date string (ISO 8601) The same instant as the Date header, in UTC at second precision — the RFC 5322 form lives in headers.Date.
example: 2026-07-21T12:03:11Z
headers object Top-level header values in unfolded wire form, keyed by canonical field name (Date, From, To, Cc, Subject, Message-ID, MIME-Version, Content-Type…).
example: {"Date":"Tue, 21 Jul 2026 14:03:11 +0200","From":"\"Ada Lovelace\" <ada.lovelace@northwind.test>","To":"\"Grace Hopper\" <grace.hopper@example.net>","Subject":"Q3 roadmap review: agenda and open questions","Message-ID":"<20260721T120311.9c1d4a7f0b23@northwind.test>","MIME-Version":"1.0","Content-Type":"multipart/alternative; boundary=\"----=_Part_4f2a91c0_8b3d17e6\""}
structure object Part tree — shape only: contentType, boundary and nested parts for containers; contentType, charset, contentTransferEncoding, decoded sizeBytes and disposition for leaves. Attachment filenames and Content-IDs live in `attachments`.
example: {"contentType":"multipart/alternative","boundary":"----=_Part_4f2a91c0_8b3d17e6","parts":[{"contentType":"text/plain","charset":"utf-8","contentTransferEncoding":"quoted-printable","sizeBytes":412},{"contentType":"text/html","charset":"utf-8","contentTransferEncoding":"quoted-printable","sizeBytes":733}]}
attachments object[] One entry per attachment part, in part order: filename, contentType, decoded sizeBytes, contentTransferEncoding and contentId.
example: [{"filename":"q3-report.pdf","contentType":"application/pdf","sizeBytes":1843,"contentTransferEncoding":"base64","contentId":"<9f0c2a71b4d8@northwind.test>"}]
bodyPreview string First 80 characters of the decoded text/plain part with whitespace collapsed, truncated with an ellipsis.
example: Hi Grace, Thanks for the quick turnaround on the last batch - the totals line…
/api/email-messages {
"data": [
{
"messageId": "<20260702T140933.e6b5fb43cb56@example.net>",
"inReplyTo": null,
"references": [],
"from": {
"name": "Marcus Nair",
"address": "marcus.nair@example.net"
},
"to": [
{
"name": "Marcus Bennett",
"address": "marcus.bennett@example.com"
}
],
"cc": [],
"subject": "Weekly metrics digest",
"date": "2026-07-02T14:09:33Z",
"headers": {
"Date": "Thu, 2 Jul 2026 08:09:33 -0600",
"From": "\"Marcus Nair\" <marcus.nair@example.net>",
"To": "\"Marcus Bennett\" <marcus.bennett@example.com>",
"Subject": "Weekly metrics digest",
"Message-ID": "<20260702T140933.e6b5fb43cb56@example.net>",
"MIME-Version": "1.0",
"Content-Type": "multipart/alternative; boundary=\"----=_Part_8f10d55d_04d4df20\""
},
"structure": {
"contentType": "multipart/alternative",
"boundary": "----=_Part_8f10d55d_04d4df20",
"parts": [
{
"contentType": "text/plain",
"charset": "utf-8",
"contentTransferEncoding": "quoted-printable",
"sizeBytes": 360
},
{
"contentType": "text/html",
…
"generatedAt": "2026-07-29T08:13:22.000Z"
}
} /api/email-messages?structure=mixed&attachments=2&seed=42&count=5 {
"data": [
{
"messageId": "<20260702T140933.d4b875a223ab@example.net>",
"inReplyTo": null,
"references": [],
"from": {
"name": "Marcus Nair",
"address": "marcus.nair@example.net"
},
"to": [
{
"name": "Marcus Bennett",
"address": "marcus.bennett@example.com"
}
],
"cc": [],
"subject": "Weekly metrics digest",
"date": "2026-07-02T14:09:33Z",
"headers": {
"Date": "Thu, 2 Jul 2026 08:09:33 -0600",
"From": "\"Marcus Nair\" <marcus.nair@example.net>",
"To": "\"Marcus Bennett\" <marcus.bennett@example.com>",
"Subject": "Weekly metrics digest",
"Message-ID": "<20260702T140933.d4b875a223ab@example.net>",
"MIME-Version": "1.0",
"Content-Type": "multipart/mixed; boundary=\"----=_Part_3b0ba5fe_d363ec65\""
},
"structure": {
"contentType": "multipart/mixed",
"boundary": "----=_Part_3b0ba5fe_d363ec65",
"parts": [
{
"contentType": "text/plain",
"charset": "utf-8",
"contentTransferEncoding": "quoted-printable",
"sizeBytes": 360
},
{
"contentType": "image/jpeg",
…
]
}
} /api/email-messages?structure=nested&attachments=1&unicode=true&count=3 {
"data": [
{
"messageId": "<20260720T223207.28fa1e70cf67@example.net>",
"inReplyTo": null,
"references": [],
"from": {
"name": "田中 陽子",
"address": "yoko.tanaka@example.net"
},
"to": [
{
"name": "José Álvarez",
"address": "jose.alvarez@example.com"
}
],
"cc": [],
"subject": "Обзор дорожной карты на III квартал",
"date": "2026-07-20T22:32:07Z",
"headers": {
"Date": "Mon, 20 Jul 2026 15:32:07 -0700",
"From": "=?utf-8?B?55Sw5LitIOmZveWtkA==?= <yoko.tanaka@example.net>",
"To": "=?utf-8?B?Sm9zw6kgw4FsdmFyZXo=?= <jose.alvarez@example.com>",
"Subject": "=?utf-8?B?0J7QsdC30L7RgCDQtNC+0YDQvtC20L3QvtC5INC60LDRgNGC?= =?utf-8?B?0Ysg0L3QsCBJSUkg0LrQstCw0YDRgtCw0Ls=?=",
"Message-ID": "<20260720T223207.28fa1e70cf67@example.net>",
"MIME-Version": "1.0",
"Content-Type": "multipart/mixed; boundary=\"----=_Part_011dc810_2416d011\""
},
"structure": {
"contentType": "multipart/mixed",
"boundary": "----=_Part_011dc810_2416d011",
"parts": [
{
"contentType": "multipart/alternative",
"boundary": "----=_Part_fd02512b_8e9f0da9",
"parts": [
{
"contentType": "text/plain",
"charset": "utf-8",
"contentTransferEncoding": "quoted-printable",
…
]
}
} /api/email-messages?encoding=base64&from=2026-01-01&to=2026-03-31&count=20 {
"data": [
{
"messageId": "<20260111T153621.e6b5fb43cb56@example.net>",
"inReplyTo": null,
"references": [],
"from": {
"name": "Marcus Nair",
"address": "marcus.nair@example.net"
},
"to": [
{
"name": "Marcus Bennett",
"address": "marcus.bennett@example.com"
}
],
"cc": [],
"subject": "Weekly metrics digest",
"date": "2026-01-11T15:36:21Z",
"headers": {
"Date": "Sun, 11 Jan 2026 09:36:21 -0600",
"From": "\"Marcus Nair\" <marcus.nair@example.net>",
"To": "\"Marcus Bennett\" <marcus.bennett@example.com>",
"Subject": "Weekly metrics digest",
"Message-ID": "<20260111T153621.e6b5fb43cb56@example.net>",
"MIME-Version": "1.0",
"Content-Type": "multipart/alternative; boundary=\"----=_Part_8f10d55d_04d4df20\""
},
"structure": {
"contentType": "multipart/alternative",
"boundary": "----=_Part_8f10d55d_04d4df20",
"parts": [
{
"contentType": "text/plain",
"charset": "utf-8",
"contentTransferEncoding": "base64",
"sizeBytes": 360
},
{
"contentType": "text/html",
…
"generatedAt": "2026-07-29T08:13:22.000Z"
}
}Returns the whole message as a string with CRLF line endings — headers, boundaries, encoded bodies and attachment parts. Save raw verbatim as a .eml file.
| Parameter | Type | Default & allowed | Description |
|---|---|---|---|
structure | enum | default: alternative allowed: plain | alternative | mixed | nested example: mixed | Part tree: 'plain' = one text/plain entity; 'alternative' = multipart/alternative with text/plain then text/html; 'mixed' = multipart/mixed with a text/plain part plus attachment parts; 'nested' = multipart/mixed wrapping a multipart/alternative plus attachment parts. |
attachments | int | default: 0 allowed: 0 – 3 example: 2 | Exact number of attachment parts. Requires structure=mixed or structure=nested; anything above 0 with 'plain' or 'alternative' is a 400. |
encoding | enum | default: quotedPrintable allowed: 7bit | quotedPrintable | base64 example: base64 | Content-Transfer-Encoding for the text parts; 'quotedPrintable' emits the literal token 'quoted-printable'. Binary attachment parts stay base64 regardless. |
unicode | boolean | default: false example: true | Use display names and a subject that contain non-ASCII characters, forcing RFC 2047 'B' encoded-words in From/To/Cc/Subject. Body text and local parts stay US-ASCII either way. |
seed | int | default: 1 allowed: 0 – 2147483647 example: 42 | Seeds every choice in the message. Pin it — together with the route's other parameters — for byte-identical output on every call. |
structure enum Part tree: 'plain' = one text/plain entity; 'alternative' = multipart/alternative with text/plain then text/html; 'mixed' = multipart/mixed with a text/plain part plus attachment parts; 'nested' = multipart/mixed wrapping a multipart/alternative plus attachment parts.
attachments int Exact number of attachment parts. Requires structure=mixed or structure=nested; anything above 0 with 'plain' or 'alternative' is a 400.
encoding enum Content-Transfer-Encoding for the text parts; 'quotedPrintable' emits the literal token 'quoted-printable'. Binary attachment parts stay base64 regardless.
unicode boolean Use display names and a subject that contain non-ASCII characters, forcing RFC 2047 'B' encoded-words in From/To/Cc/Subject. Body text and local parts stay US-ASCII either way.
seed int Seeds every choice in the message. Pin it — together with the route's other parameters — for byte-identical output on every call.
| Parameter | Type | Default & allowed | Description |
|---|---|---|---|
fields | list | example: raw,messageId | Return only these fields (comma-separated). Mutually exclusive with 'exclude'. |
exclude | list | example: lineCount | Return all fields except these (comma-separated). |
pretty | boolean | default: false example: true | Pretty-print the JSON response. |
unwrap | boolean | default: false example: true | Drop the envelope: return the raw array/object without data/meta wrapper. |
fields list Return only these fields (comma-separated). Mutually exclusive with 'exclude'.
exclude list Return all fields except these (comma-separated).
pretty boolean Pretty-print the JSON response.
unwrap boolean Drop the envelope: return the raw array/object without data/meta wrapper.
| Field | Type | Description | Example |
|---|---|---|---|
raw | string | The complete message: CRLF line endings, pure US-ASCII, no trailing newline. Never larger than about 16 KB (three base64 attachments of at most 2400 octets each). | Date: Tue, 21 Jul 2026 14:03:11 +0200 From: "Ada Lovelace" <ada.lovelace@northwind.test> … |
messageId | string | The Message-ID of this message, including angle brackets. | <20260721T120311.9c1d4a7f0b23@northwind.test> |
subject | string | Decoded subject — the wire form inside `raw` is RFC 2047 encoded-words when unicode=true. | Q3 roadmap review: agenda and open questions |
date | string (ISO 8601) | The instant in the Date header, in UTC. Derived from `seed` inside a fixed 2020-01-01…2029-12-31 window, so the message never changes over time. | 2026-07-21T12:03:11Z |
structure | object | The part tree of this exact message, with the boundary strings that appear in `raw`. | {"contentType":"multipart/alternative","boundary":"----=_Part_4f2a91c0_8b3d17e6","parts":[{"contentType":"text/plain","charset":"utf-8","contentTransferEncoding":"quoted-printable","sizeBytes":412},{"contentType":"text/html","charset":"utf-8","contentTransferEncoding":"quoted-printable","sizeBytes":733}]} |
attachments | object[] | One entry per attachment part, in part order: filename, contentType, decoded sizeBytes, contentTransferEncoding and contentId. | [{"filename":"q3-report.pdf","contentType":"application/pdf","sizeBytes":1843,"contentTransferEncoding":"base64","contentId":"<9f0c2a71b4d8@northwind.test>"}] |
boundaries | string[] | Every boundary string used, outermost first. Empty for structure=plain. None of them occurs inside any part body. | ["----=_Part_4f2a91c0_8b3d17e6"] |
sizeBytes | integer | Byte length of `raw`. Equal to its character count, because the message is pure US-ASCII. | 1893 |
lineCount | integer | Number of CRLF-separated lines in `raw`. Every line is at most 998 characters, per RFC 5322 §2.1.1. | 42 |
raw string The complete message: CRLF line endings, pure US-ASCII, no trailing newline. Never larger than about 16 KB (three base64 attachments of at most 2400 octets each).
example: Date: Tue, 21 Jul 2026 14:03:11 +0200 From: "Ada Lovelace" <ada.lovelace@northwind.test> …
messageId string The Message-ID of this message, including angle brackets.
example: <20260721T120311.9c1d4a7f0b23@northwind.test>
subject string Decoded subject — the wire form inside `raw` is RFC 2047 encoded-words when unicode=true.
example: Q3 roadmap review: agenda and open questions
date string (ISO 8601) The instant in the Date header, in UTC. Derived from `seed` inside a fixed 2020-01-01…2029-12-31 window, so the message never changes over time.
example: 2026-07-21T12:03:11Z
structure object The part tree of this exact message, with the boundary strings that appear in `raw`.
example: {"contentType":"multipart/alternative","boundary":"----=_Part_4f2a91c0_8b3d17e6","parts":[{"contentType":"text/plain","charset":"utf-8","contentTransferEncoding":"quoted-printable","sizeBytes":412},{"contentType":"text/html","charset":"utf-8","contentTransferEncoding":"quoted-printable","sizeBytes":733}]}
attachments object[] One entry per attachment part, in part order: filename, contentType, decoded sizeBytes, contentTransferEncoding and contentId.
example: [{"filename":"q3-report.pdf","contentType":"application/pdf","sizeBytes":1843,"contentTransferEncoding":"base64","contentId":"<9f0c2a71b4d8@northwind.test>"}]
boundaries string[] Every boundary string used, outermost first. Empty for structure=plain. None of them occurs inside any part body.
example: ["----=_Part_4f2a91c0_8b3d17e6"]
sizeBytes integer Byte length of `raw`. Equal to its character count, because the message is pure US-ASCII.
example: 1893
lineCount integer Number of CRLF-separated lines in `raw`. Every line is at most 998 characters, per RFC 5322 §2.1.1.
example: 42
/api/email-messages/raw {
"data": {
"raw": "Date: Tue, 4 Jan 2022 15:26:55 -0500\r\nFrom: \"Ruth Lovelace\" <ruth.lovelace@kestrel.test>\r\nTo: \"Marcus Duarte\" <marcus.duarte@example.com>\r\nCc: \"Maya Ferreira\" <maya.ferreira@northwind.test>\r\nSubject: Storage quota is at 82 percent\r\nMessage-ID: <20220104T202655.3af16ffebb17@kestrel.test>\r\nMIME-Version: 1.0\r\nContent-Type: multipart/alternative; boundary=\"----=_Part_68265634_fd45b22f\"\r\n\r\nThis is a multipart message in MIME format.\r\n------=_Part_68265634_fd45b22f\r\nContent-Type: text/plain; charset=utf-8\r\nContent-Transfer-Encoding: quoted-printable\r\n\r\nHi Marcus,\r\n\r\nCould you confirm the owner for the second workstream before Friday? I woul=\r\nd like to close the tracker.\r\n\r\nWe are holding the release until the migration finishes, which should be so=\r\nme time on Wednesday afternoon.\r\n\r\nMore detail: https://kestrel.test/reports/east-c6c5?utm_source=3Ddigest&utm=\r\n_medium=3Demail\r\n\r\n--=20\r\nRuth Lovelace\r\nData, Kestrel Analytics\r\n------=_Part_68265634_fd45b22f\r\nContent-Type: text/html; charset=utf-8\r\nContent-Transfer-Encoding: quoted-printable\r\n\r\n<!DOCTYPE html>\r\n<html lang=3D\"en\">\r\n<body>\r\n<p>Hi Marcus,</p>\r\n<p>Could you confirm the owner for the second workstream before Friday? I=\r\n would like to close the tracker.</p>\r\n<p>We are holding the release until the migration finishes, which should be=\r\n some time on Wednesday afternoon.</p>\r\n<p><a href=3D\"https://kestrel.test/reports/east-c6c5?utm_source=3Ddigest&am=\r\np;utm_medium=3Demail\">Open the report</a></p>\r\n<p style=3D\"color:#6b7280\">Ruth Lovelace<br>Data, Kestrel Analytics</p>\r\n</body>\r\n</html>\r\n------=_Part_68265634_fd45b22f--",
"messageId": "<20220104T202655.3af16ffebb17@kestrel.test>",
"subject": "Storage quota is at 82 percent",
"date": "2022-01-04T20:26:55Z",
"structure": {
"contentType": "multipart/alternative",
"boundary": "----=_Part_68265634_fd45b22f",
"parts": [
{
"contentType": "text/plain",
"charset": "utf-8",
"contentTransferEncoding": "quoted-printable",
"sizeBytes": 364
},
{
"contentType": "text/html",
"charset": "utf-8",
"contentTransferEncoding": "quoted-printable",
"sizeBytes": 492
}
]
},
"attachments": [],
"boundaries": [
"----=_Part_68265634_fd45b22f"
],
"sizeBytes": 1598,
"lineCount": 46
},
"meta": {
"endpoint": "email-messages",
"route": "/raw",
"params": {
"structure": "alternative",
"attachments": 0,
"encoding": "quotedPrintable",
"unicode": false,
"seed": 1
},
"generatedAt": "2026-07-29T08:13:22.000Z"
}
} /api/email-messages/raw?structure=nested&attachments=2&seed=7 {
"data": {
"raw": "Date: Mon, 12 Oct 2026 05:30:00 -0600\r\nFrom: \"Isaac Hopper\" <isaac.hopper@example.com>\r\nTo: \"Alan Bennett\" <alan.bennett@meridian.test>\r\nCc: \"Isaac Moreau\" <isaac.moreau@northwind.test>\r\nSubject: Deploy window moved to Thursday 09:00\r\nMessage-ID: <20261012T113000.be33ae467d4a@example.com>\r\nMIME-Version: 1.0\r\nContent-Type: multipart/mixed; boundary=\"----=_Part_64961e4a_814a8074\"\r\n\r\nThis is a multipart message in MIME format.\r\n------=_Part_64961e4a_814a8074\r\nContent-Type: multipart/alternative; boundary=\"----=_Part_47a6f811_20ed7944\"\r\n\r\n------=_Part_47a6f811_20ed7944\r\nContent-Type: text/plain; charset=utf-8\r\nContent-Transfer-Encoding: quoted-printable\r\n\r\nHi Alan,\r\n\r\nNothing urgent, but the archive job has been running long enough that it is=\r\n worth a look this week.\r\n\r\nWe are holding the release until the migration finishes, which should be so=\r\nme time on Wednesday afternoon.\r\n\r\nMore detail: https://example.com/reports/central-d963?utm_source=3Ddigest&u=\r\ntm_medium=3Demail\r\n\r\n--=20\r\nIsaac Hopper\r\nSupport, Example Corp\r\n------=_Part_47a6f811_20ed7944\r\nContent-Type: text/html; charset=utf-8\r\nContent-Transfer-Encoding: quoted-printable\r\n\r\n<!DOCTYPE html>\r\n<html lang=3D\"en\">\r\n<body>\r\n<p>Hi Alan,</p>\r\n<p>Nothing urgent, but the archive job has been running long enough that it=\r\n is worth a look this week.</p>\r\n<p>We are holding the release until the migration finishes, which should be=\r\n some time on Wednesday afternoon.</p>\r\n<p><a href=3D\"https://example.com/reports/central-d963?utm_source=3Ddigest&=\r\namp;utm_medium=3Demail\">Open the report</a></p>\r\n<p style=3D\"color:#6b7280\">Isaac Hopper<br>Support, Example Corp</p>\r\n</body>\r\n</html>\r\n------=_Part_47a6f811_20ed7944--\r\n------=_Part_64961e4a_814a8074\r\nContent-Type: image/jpeg\r\nContent-Transfer-Encoding: base64\r\nContent-Disposition: attachment; filename=\"scan.jpg\"\r\nContent-ID: <12615a93725d@example.com>\r\n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\r\n------=_Part_64961e4a_814a8074\r\nContent-Type: application/pdf\r\nContent-Transfer-Encoding: base64\r\nContent-Disposition: attachment; filename=\"q3-report.pdf\"\r\nContent-ID: <bba837db838b@example.com>\r\n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\r\nd41+\r\n------=_Part_64961e4a_814a8074--",
"messageId": "<20261012T113000.be33ae467d4a@example.com>",
"subject": "Deploy window moved to Thursday 09:00",
"date": "2026-10-12T11:30:00Z",
"structure": {
"contentType": "multipart/mixed",
"boundary": "----=_Part_64961e4a_814a8074",
"parts": [
{
"contentType": "multipart/alternative",
"boundary": "----=_Part_47a6f811_20ed7944",
"parts": [
{
"contentType": "text/plain",
"charset": "utf-8",
"contentTransferEncoding": "quoted-printable",
"sizeBytes": 357
},
{
"contentType": "text/html",
"charset": "utf-8",
"contentTransferEncoding": "quoted-printable",
"sizeBytes": 485
}
]
},
{
"contentType": "image/jpeg",
"contentTransferEncoding": "base64",
"sizeBytes": 1132,
"disposition": "attachment"
},
{
"contentType": "application/pdf",
"contentTransferEncoding": "base64",
"sizeBytes": 744,
"disposition": "attachment"
}
…
]
}
} /api/email-messages/raw?structure=plain&encoding=7bit {
"data": {
"raw": "Date: Tue, 4 Jan 2022 15:26:55 -0500\r\nFrom: \"Ruth Lovelace\" <ruth.lovelace@kestrel.test>\r\nTo: \"Marcus Duarte\" <marcus.duarte@example.com>\r\nCc: \"Maya Ferreira\" <maya.ferreira@northwind.test>\r\nSubject: Storage quota is at 82 percent\r\nMessage-ID: <20220104T202655.3af16ffebb17@kestrel.test>\r\nMIME-Version: 1.0\r\nContent-Type: text/plain; charset=utf-8\r\nContent-Transfer-Encoding: 7bit\r\n\r\nHi Marcus,\r\n\r\nCould you confirm the owner for the second workstream before Friday? I would like to close the tracker.\r\n\r\nWe are holding the release until the migration finishes, which should be some time on Wednesday afternoon.\r\n\r\nMore detail: https://kestrel.test/reports/east-c6c5?utm_source=digest&utm_medium=email\r\n\r\n-- \r\nRuth Lovelace\r\nData, Kestrel Analytics",
"messageId": "<20220104T202655.3af16ffebb17@kestrel.test>",
"subject": "Storage quota is at 82 percent",
"date": "2022-01-04T20:26:55Z",
"structure": {
"contentType": "text/plain",
"charset": "utf-8",
"contentTransferEncoding": "7bit",
"sizeBytes": 364
},
"attachments": [],
"boundaries": [],
"sizeBytes": 748,
"lineCount": 21
},
"meta": {
"endpoint": "email-messages",
"route": "/raw",
"params": {
"structure": "plain",
"attachments": 0,
"encoding": "7bit",
"unicode": false,
"seed": 1
},
"generatedAt": "2026-07-29T08:13:22.000Z"
}
} /api/email-messages/raw?encoding=base64&unicode=true&seed=99 {
"data": {
"raw": "Date: Thu, 4 Jan 2029 20:41:26 +0900\r\nFrom: =?utf-8?B?w5NsYWZ1ciBKw7Nuc3Nvbg==?= <olafur.jonsson@example.com>\r\nTo: =?utf-8?B?Wm/DqyBNw7xsbGVy?= <zoe.mueller@orbital.test>\r\nCc: =?utf-8?B?Wm/DqyBNw7xsbGVy?= <zoe.mueller@bluewave.test>\r\nSubject: =?utf-8?B?QcOxYWRpciBzb3BvcnRlIHBhcmEgYsO6c3F1ZWRhIGF2YW56?=\r\n =?utf-8?B?YWRh?=\r\nMessage-ID: <20290104T114126.b420eca9967b@example.com>\r\nMIME-Version: 1.0\r\nContent-Type: multipart/alternative; boundary=\"----=_Part_0ba2ce56_97206372\"\r\n\r\nThis is a multipart message in MIME format.\r\n------=_Part_0ba2ce56_97206372\r\nContent-Type: text/plain; charset=utf-8\r\nContent-Transfer-Encoding: base64\r\n\r\nSGkgWm9lLA0KDQpJIGhhdmUgcGVuY2lsbGVkIGluIGEgc2hvcnQgY2FsbCBmb3IgVHVlc2RheTsg\r\nbW92ZSBpdCBpZiB0aGF0IGNsYXNoZXMgd2l0aCB0aGUgY3VzdG9tZXIgd29ya3Nob3AuDQoNClRo\r\nYW5rcyBmb3IgdGhlIHF1aWNrIHR1cm5hcm91bmQgb24gdGhlIGxhc3QgYmF0Y2ggLSB0aGUgdG90\r\nYWxzIGxpbmUgdXAgd2l0aCB3aGF0IHdlIHNhdyBpbiBzdGFnaW5nLg0KDQpNb3JlIGRldGFpbDog\r\naHR0cHM6Ly9leGFtcGxlLmNvbS9yZXBvcnRzL2liZXJpYS04MjY5P3V0bV9zb3VyY2U9ZGlnZXN0\r\nJnV0bV9tZWRpdW09ZW1haWwNCg0KLS0gDQpPbGFmdXIgSm9uc3Nvbg0KU3VwcG9ydCwgRXhhbXBs\r\nZSBDb3Jw\r\n------=_Part_0ba2ce56_97206372\r\nContent-Type: text/html; charset=utf-8\r\nContent-Transfer-Encoding: base64\r\n\r\nPCFET0NUWVBFIGh0bWw+DQo8aHRtbCBsYW5nPSJlbiI+DQo8Ym9keT4NCjxwPkhpIFpvZSw8L3A+\r\nDQo8cD5JIGhhdmUgcGVuY2lsbGVkIGluIGEgc2hvcnQgY2FsbCBmb3IgVHVlc2RheTsgbW92ZSBp\r\ndCBpZiB0aGF0IGNsYXNoZXMgd2l0aCB0aGUgY3VzdG9tZXIgd29ya3Nob3AuPC9wPg0KPHA+VGhh\r\nbmtzIGZvciB0aGUgcXVpY2sgdHVybmFyb3VuZCBvbiB0aGUgbGFzdCBiYXRjaCAtIHRoZSB0b3Rh\r\nbHMgbGluZSB1cCB3aXRoIHdoYXQgd2Ugc2F3IGluIHN0YWdpbmcuPC9wPg0KPHA+PGEgaHJlZj0i\r\naHR0cHM6Ly9leGFtcGxlLmNvbS9yZXBvcnRzL2liZXJpYS04MjY5P3V0bV9zb3VyY2U9ZGlnZXN0\r\nJmFtcDt1dG1fbWVkaXVtPWVtYWlsIj5PcGVuIHRoZSByZXBvcnQ8L2E+PC9wPg0KPHAgc3R5bGU9\r\nImNvbG9yOiM2YjcyODAiPk9sYWZ1ciBKb25zc29uPGJyPlN1cHBvcnQsIEV4YW1wbGUgQ29ycDwv\r\ncD4NCjwvYm9keT4NCjwvaHRtbD4=\r\n------=_Part_0ba2ce56_97206372--",
"messageId": "<20290104T114126.b420eca9967b@example.com>",
"subject": "Añadir soporte para búsqueda avanzada",
"date": "2029-01-04T11:41:26Z",
"structure": {
"contentType": "multipart/alternative",
"boundary": "----=_Part_0ba2ce56_97206372",
"parts": [
{
"contentType": "text/plain",
"charset": "utf-8",
"contentTransferEncoding": "base64",
"sizeBytes": 348
},
{
"contentType": "text/html",
"charset": "utf-8",
"contentTransferEncoding": "base64",
"sizeBytes": 476
}
]
},
"attachments": [],
"boundaries": [
"----=_Part_0ba2ce56_97206372"
],
"sizeBytes": 1907,
"lineCount": 36
},
"meta": {
"endpoint": "email-messages",
"route": "/raw",
"params": {
"structure": "alternative",
"attachments": 0,
"encoding": "base64",
"unicode": true,
"seed": 99
},
"generatedAt": "2026-07-29T08:13:22.000Z"
}
}Returns the root message followed by depth replies. Each reply's In-Reply-To is exactly its parent's Message-ID, and its References is the parent's References plus the parent's Message-ID (RFC 5322 §3.6.4).
| Parameter | Type | Default & allowed | Description |
|---|---|---|---|
depth | int | default: 3 allowed: 1 – 8 example: 5 | Number of replies after the root message; the chain therefore holds depth + 1 messages. |
structure | enum | default: alternative allowed: plain | alternative | mixed | nested example: plain | Part tree: 'plain' = one text/plain entity; 'alternative' = multipart/alternative with text/plain then text/html; 'mixed' = multipart/mixed with a text/plain part plus attachment parts; 'nested' = multipart/mixed wrapping a multipart/alternative plus attachment parts. |
from | date | example: 2026-05-04 | Earliest possible date for the root message, which lands within 12 hours of it; replies then follow at 7 minutes to 20 hours apart. Every instant in the chain is a whole second (a sub-second 'from' rounds up), because an RFC 5322 Date has second precision. Defaults to 7 days before today (UTC). |
seed | int | default: 1 allowed: 0 – 2147483647 example: 42 | Seeds every choice in the message. Pin it — together with the route's other parameters — for byte-identical output on every call. |
depth int Number of replies after the root message; the chain therefore holds depth + 1 messages.
structure enum Part tree: 'plain' = one text/plain entity; 'alternative' = multipart/alternative with text/plain then text/html; 'mixed' = multipart/mixed with a text/plain part plus attachment parts; 'nested' = multipart/mixed wrapping a multipart/alternative plus attachment parts.
from date Earliest possible date for the root message, which lands within 12 hours of it; replies then follow at 7 minutes to 20 hours apart. Every instant in the chain is a whole second (a sub-second 'from' rounds up), because an RFC 5322 Date has second precision. Defaults to 7 days before today (UTC).
seed int Seeds every choice in the message. Pin it — together with the route's other parameters — for byte-identical output on every call.
| Parameter | Type | Default & allowed | Description |
|---|---|---|---|
fields | list | example: subject,depth | Return only these fields (comma-separated). Mutually exclusive with 'exclude'. |
exclude | list | example: messages | Return all fields except these (comma-separated). |
pretty | boolean | default: false example: true | Pretty-print the JSON response. |
unwrap | boolean | default: false example: true | Drop the envelope: return the raw array/object without data/meta wrapper. |
fields list Return only these fields (comma-separated). Mutually exclusive with 'exclude'.
exclude list Return all fields except these (comma-separated).
pretty boolean Pretty-print the JSON response.
unwrap boolean Drop the envelope: return the raw array/object without data/meta wrapper.
| Field | Type | Description | Example |
|---|---|---|---|
subject | string | Base subject. The root uses it verbatim; every reply uses 'Re: ' plus the base (never stacked). | Q3 roadmap review: agenda and open questions |
depth | integer (1-8) | Replies after the root, as requested. | 3 |
messageCount | integer | Messages in the chain — always depth + 1. | 4 |
participants | object[] | The two or three mailboxes in the conversation, in send-rotation order: message i is sent by participants[i % participants.length]. Everyone else on a message is a To or Cc recipient, so at depth=1 a third participant is only ever copied, never a sender. | [{"name":"Ada Lovelace","address":"ada.lovelace@northwind.test"},{"name":"Grace Hopper","address":"grace.hopper@example.net"},{"name":"Marcus Bennett","address":"marcus.bennett@meridian.test"}] |
messages | object[] | The chain, oldest first. Each entry has index, messageId, inReplyTo, references, from, to, cc, subject, date, headers, structure and bodyPreview. Thread messages never carry attachment parts. | [{"index":0,"messageId":"<20260721T120311.9c1d4a7f0b23@northwind.test>","inReplyTo":null,"references":[],"from":{"name":"Ada Lovelace","address":"ada.lovelace@northwind.test"},"to":[{"name":"Grace Hopper","address":"grace.hopper@example.net"}],"cc":[{"name":"Marcus Bennett","address":"marcus.bennett@meridian.test"}],"subject":"Q3 roadmap review: agenda and open questions","date":"2026-07-21T12:03:11Z","headers":{"Date":"Tue, 21 Jul 2026 14:03:11 +0200","From":"\"Ada Lovelace\" <ada.lovelace@northwind.test>","To":"\"Grace Hopper\" <grace.hopper@example.net>","Cc":"\"Marcus Bennett\" <marcus.bennett@meridian.test>","Subject":"Q3 roadmap review: agenda and open questions","Message-ID":"<20260721T120311.9c1d4a7f0b23@northwind.test>","MIME-Version":"1.0","Content-Type":"text/plain; charset=utf-8","Content-Transfer-Encoding":"quoted-printable"},"structure":{"contentType":"text/plain","charset":"utf-8","contentTransferEncoding":"quoted-printable","sizeBytes":412},"bodyPreview":"Hi Grace, Thanks for the quick turnaround on the last batch - the totals line…"},{"index":1,"messageId":"<20260721T224408.3e81b6cf90a4@example.net>","inReplyTo":"<20260721T120311.9c1d4a7f0b23@northwind.test>","references":["<20260721T120311.9c1d4a7f0b23@northwind.test>"],"from":{"name":"Grace Hopper","address":"grace.hopper@example.net"},"to":[{"name":"Ada Lovelace","address":"ada.lovelace@northwind.test"}],"cc":[{"name":"Marcus Bennett","address":"marcus.bennett@meridian.test"}],"subject":"Re: Q3 roadmap review: agenda and open questions","date":"2026-07-21T22:44:08Z","headers":{"Date":"Wed, 22 Jul 2026 07:44:08 +0900","From":"\"Grace Hopper\" <grace.hopper@example.net>","To":"\"Ada Lovelace\" <ada.lovelace@northwind.test>","Cc":"\"Marcus Bennett\" <marcus.bennett@meridian.test>","Subject":"Re: Q3 roadmap review: agenda and open questions","Message-ID":"<20260721T224408.3e81b6cf90a4@example.net>","In-Reply-To":"<20260721T120311.9c1d4a7f0b23@northwind.test>","References":"<20260721T120311.9c1d4a7f0b23@northwind.test>","MIME-Version":"1.0","Content-Type":"text/plain; charset=utf-8","Content-Transfer-Encoding":"quoted-printable"},"structure":{"contentType":"text/plain","charset":"utf-8","contentTransferEncoding":"quoted-printable","sizeBytes":338},"bodyPreview":"Hi Ada, Looks right. The only thing I would add is a note about the retry budge…"}] |
subject string Base subject. The root uses it verbatim; every reply uses 'Re: ' plus the base (never stacked).
example: Q3 roadmap review: agenda and open questions
depth integer (1-8) Replies after the root, as requested.
example: 3
messageCount integer Messages in the chain — always depth + 1.
example: 4
participants object[] The two or three mailboxes in the conversation, in send-rotation order: message i is sent by participants[i % participants.length]. Everyone else on a message is a To or Cc recipient, so at depth=1 a third participant is only ever copied, never a sender.
example: [{"name":"Ada Lovelace","address":"ada.lovelace@northwind.test"},{"name":"Grace Hopper","address":"grace.hopper@example.net"},{"name":"Marcus Bennett","address":"marcus.bennett@meridian.test"}]
messages object[] The chain, oldest first. Each entry has index, messageId, inReplyTo, references, from, to, cc, subject, date, headers, structure and bodyPreview. Thread messages never carry attachment parts.
example: [{"index":0,"messageId":"<20260721T120311.9c1d4a7f0b23@northwind.test>","inReplyTo":null,"references":[],"from":{"name":"Ada Lovelace","address":"ada.lovelace@northwind.test"},"to":[{"name":"Grace Hopper","address":"grace.hopper@example.net"}],"cc":[{"name":"Marcus Bennett","address":"marcus.bennett@meridian.test"}],"subject":"Q3 roadmap review: agenda and open questions","date":"2026-07-21T12:03:11Z","headers":{"Date":"Tue, 21 Jul 2026 14:03:11 +0200","From":"\"Ada Lovelace\" <ada.lovelace@northwind.test>","To":"\"Grace Hopper\" <grace.hopper@example.net>","Cc":"\"Marcus Bennett\" <marcus.bennett@meridian.test>","Subject":"Q3 roadmap review: agenda and open questions","Message-ID":"<20260721T120311.9c1d4a7f0b23@northwind.test>","MIME-Version":"1.0","Content-Type":"text/plain; charset=utf-8","Content-Transfer-Encoding":"quoted-printable"},"structure":{"contentType":"text/plain","charset":"utf-8","contentTransferEncoding":"quoted-printable","sizeBytes":412},"bodyPreview":"Hi Grace, Thanks for the quick turnaround on the last batch - the totals line…"},{"index":1,"messageId":"<20260721T224408.3e81b6cf90a4@example.net>","inReplyTo":"<20260721T120311.9c1d4a7f0b23@northwind.test>","references":["<20260721T120311.9c1d4a7f0b23@northwind.test>"],"from":{"name":"Grace Hopper","address":"grace.hopper@example.net"},"to":[{"name":"Ada Lovelace","address":"ada.lovelace@northwind.test"}],"cc":[{"name":"Marcus Bennett","address":"marcus.bennett@meridian.test"}],"subject":"Re: Q3 roadmap review: agenda and open questions","date":"2026-07-21T22:44:08Z","headers":{"Date":"Wed, 22 Jul 2026 07:44:08 +0900","From":"\"Grace Hopper\" <grace.hopper@example.net>","To":"\"Ada Lovelace\" <ada.lovelace@northwind.test>","Cc":"\"Marcus Bennett\" <marcus.bennett@meridian.test>","Subject":"Re: Q3 roadmap review: agenda and open questions","Message-ID":"<20260721T224408.3e81b6cf90a4@example.net>","In-Reply-To":"<20260721T120311.9c1d4a7f0b23@northwind.test>","References":"<20260721T120311.9c1d4a7f0b23@northwind.test>","MIME-Version":"1.0","Content-Type":"text/plain; charset=utf-8","Content-Transfer-Encoding":"quoted-printable"},"structure":{"contentType":"text/plain","charset":"utf-8","contentTransferEncoding":"quoted-printable","sizeBytes":338},"bodyPreview":"Hi Ada, Looks right. The only thing I would add is a note about the retry budge…"}]
/api/email-messages/thread {
"data": {
"subject": "Storage quota is at 82 percent",
"depth": 3,
"messageCount": 4,
"participants": [
{
"name": "Ruth Lovelace",
"address": "ruth.lovelace@kestrel.test"
},
{
"name": "Priya Duarte",
"address": "priya.duarte@example.com"
}
],
"messages": [
{
"index": 0,
"messageId": "<20260722T085421.fdc7372805dc@kestrel.test>",
"inReplyTo": null,
"references": [],
"from": {
"name": "Ruth Lovelace",
"address": "ruth.lovelace@kestrel.test"
},
"to": [
{
"name": "Priya Duarte",
"address": "priya.duarte@example.com"
}
],
"cc": [],
"subject": "Storage quota is at 82 percent",
"date": "2026-07-22T08:54:21Z",
"headers": {
"Date": "Wed, 22 Jul 2026 00:54:21 -0800",
"From": "\"Ruth Lovelace\" <ruth.lovelace@kestrel.test>",
"To": "\"Priya Duarte\" <priya.duarte@example.com>",
"Subject": "Storage quota is at 82 percent",
"Message-ID": "<20260722T085421.fdc7372805dc@kestrel.test>",
…
"generatedAt": "2026-07-29T08:13:22.000Z"
}
} /api/email-messages/thread?depth=8&from=2026-05-04&seed=11 {
"data": {
"subject": "Contract renewal - next steps",
"depth": 8,
"messageCount": 9,
"participants": [
{
"name": "Tobias Nair",
"address": "tobias.nair@acme.test"
},
{
"name": "Julian Halvorsen",
"address": "julian.halvorsen@northwind.test"
}
],
"messages": [
{
"index": 0,
"messageId": "<20260504T031539.8059e3f02c61@acme.test>",
"inReplyTo": null,
"references": [],
"from": {
"name": "Tobias Nair",
"address": "tobias.nair@acme.test"
},
"to": [
{
"name": "Julian Halvorsen",
"address": "julian.halvorsen@northwind.test"
}
],
"cc": [],
"subject": "Contract renewal - next steps",
"date": "2026-05-04T03:15:39Z",
"headers": {
"Date": "Mon, 4 May 2026 12:15:39 +0900",
"From": "\"Tobias Nair\" <tobias.nair@acme.test>",
"To": "\"Julian Halvorsen\" <julian.halvorsen@northwind.test>",
"Subject": "Contract renewal - next steps",
"Message-ID": "<20260504T031539.8059e3f02c61@acme.test>",
…
"generatedAt": "2026-07-29T08:13:22.000Z"
}
} /api/email-messages/thread?depth=2&structure=plain {
"data": {
"subject": "Storage quota is at 82 percent",
"depth": 2,
"messageCount": 3,
"participants": [
{
"name": "Ruth Lovelace",
"address": "ruth.lovelace@kestrel.test"
},
{
"name": "Priya Duarte",
"address": "priya.duarte@example.com"
}
],
"messages": [
{
"index": 0,
"messageId": "<20260722T085421.fdc7372805dc@kestrel.test>",
"inReplyTo": null,
"references": [],
"from": {
"name": "Ruth Lovelace",
"address": "ruth.lovelace@kestrel.test"
},
"to": [
{
"name": "Priya Duarte",
"address": "priya.duarte@example.com"
}
],
"cc": [],
"subject": "Storage quota is at 82 percent",
"date": "2026-07-22T08:54:21Z",
"headers": {
"Date": "Wed, 22 Jul 2026 00:54:21 -0800",
"From": "\"Ruth Lovelace\" <ruth.lovelace@kestrel.test>",
"To": "\"Priya Duarte\" <priya.duarte@example.com>",
"Subject": "Storage quota is at 82 percent",
"Message-ID": "<20260722T085421.fdc7372805dc@kestrel.test>",
…
"generatedAt": "2026-07-29T08:13:22.000Z"
}
}Generates RFC 5322 / MIME messages you can point a parser at: structured records on the root route, one complete raw message on /raw, and a linked reply chain on /thread. The invariants below are the reason this exists — they are exactly the things a hand-written fixture gets subtly wrong.
/thread chain, In-Reply-To is exactly the parent's Message-ID, and References is the parent's References followed by the parent's Message-ID — root first, ending with the direct parent (RFC 5322 §3.6.4). That is the rule broken thread views get wrong, and ?depth=8 gives you eight generations to test a grouping algorithm against.base64 bodies wrap at 76 characters, quotedPrintable emits =3D for literal equals signs, soft-breaks with a trailing = at 76 characters and escapes the trailing space of the -- signature separator, and 7bit is only ever used for bodies that really are US-ASCII.multipart/alternative, text/plain precedes text/html (least to most faithful, RFC 2046 §5.1.4). Date is an RFC 5322 date-time such as Tue, 21 Jul 2026 14:03:11 +0200 — not ISO 8601; the ISO form of the same instant is the date field. Long headers fold at 76 characters with CRLF plus a single space, and unfold back to the original byte for byte.Structures. plain is a single text/plain entity. alternative is multipart/alternative [text/plain, text/html]. mixed is multipart/mixed [text/plain, attachments…]. nested is multipart/mixed [multipart/alternative [text/plain, text/html], attachments…]. attachments above 0 therefore requires mixed or nested; asking for one on plain or alternative is a 400 rather than a silently promoted structure.
unicode=true switches to display names and subjects that genuinely contain non-ASCII (Latin diacritics, Cyrillic, CJK, one emoji) so From, To, Cc and Subject carry RFC 2047 B encoded-words. Local parts and body text stay US-ASCII — this API never emits SMTPUTF8 addresses, and the whole raw message is pure 7-bit ASCII.
Note on names: the from and to query parameters bound the date window; the from and to fields in each record are mailboxes. Supply exactly one bound and the other resolves 30 days away, so either works on its own. YYYY-MM-DD means midnight UTC — pass a timestamp to cover that whole day — and because an RFC 5322 Date carries no fraction of a second, a window that contains no whole second (say 10:00:00.200Z…10:00:00.800Z) is a 400 rather than a rounded guess.
example.com, example.net, example.org, or a label under the reserved .test TLD. These fixtures cannot be used to seed a real send.export.csv and notes.txt really are CSV and plain text, but chart.png, scan.jpg, q3-report.pdf and logs.zip are filler octets with the right Content-Type and a sizeBytes that matches the decoded length. They will not open in an image or PDF viewer..eml and redacting it — along with its privacy risk.multipart/related and cid: image references, S/MIME and PGP, message/rfc822 forwarding, DKIM/SPF/Authentication-Results headers, trace headers (Received), and 8-bit or binary transfer encodings. Attachment parts do carry a Content-ID (RFC 2045 §7) because real clients emit one, but nothing in the HTML body references it with a cid: URL — that would need multipart/related.sizeBytes counts exactly what raw contains; add a newline yourself if your tooling expects a POSIX-style text file.Call /api/email-messages/raw and save the raw field verbatim as sample.eml. It is a complete RFC 5322 message in pure US-ASCII with CRLF line endings, and the same query returns byte-identical output every time — safe to commit as a golden file.
In-Reply-To holds exactly the parent's Message-ID. References holds the parent's References followed by the parent's Message-ID, so it reads root first and ends with the direct parent (RFC 5322 §3.6.4). /thread?depth=8 returns the whole chain so you can assert against it.
No. Every address, Message-ID and Content-ID domain is an RFC 2606 reserved name — example.com/.net/.org or a .test label — so nothing resolves to a real mail server and no fixture can seed a real send.
No. export.csv and notes.txt are genuine CSV and plain text, but the PNG, JPEG, PDF and ZIP parts are generated octets with the correct Content-Type and a sizeBytes that matches the decoded length. They are base64-correct but will not open in a viewer.
No, and we do not claim to. Outlook, Gmail and Apple Mail each deviate from the RFCs in ways we cannot verify; these fixtures follow the specifications, and pretending otherwise would be dishonest.
No — headers.Date is an RFC 5322 date-time such as Tue, 21 Jul 2026 14:03:11 +0200, including a real UTC offset. The date field carries the same instant in ISO 8601 UTC so you can compare the two.
Fake email addresses with name-derived usernames on guaranteed non-deliverable domains (example.com/net/org and .test) — or stamp your own with ?domain=.
Bounded fake direct, group and support conversations with valid participant references, chronological messages and exact unread counts.
Generate channel-specific notifications with safe recipients, bounded send attempts and exact sent/delivered/read/failure dates.
Fake file metadata — kebab-case names, the correct MIME type for every extension, plausible per-kind sizes, unix paths and seeded SHA-256-style checksums.
The complete IANA media type registry with file extensions merged in — look up any type or extension, or strictly parse a Content-Type value into its parts.
Generate safe DNS record fixtures with type-correct RDATA and coherent SRV RRsets, using reserved domains and documentation addresses only.