4chan Catalog API
Per-board catalog snapshot containing every OP and its preview replies, grouped by index page.
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OpenAPI Specification
openapi: 3.2.0
info:
title: 4chan Read-Only JSON Archive Catalog API
description: 'Read-only JSON API for the 4chan and 4channel imageboards, originally launched in September 2012. All endpoints are served as static JSON documents from `a.4cdn.org` over `http://` or `https://`. The API exposes only the public, anonymous read surface of the site: board metadata, board catalogs, board threadlists, archive listings, board index pages, and individual thread documents.
There is no authentication, no posting, and no per-user write surface. Only `GET`, `HEAD`, and `OPTIONS` are accepted. CORS is enabled only for origins `boards.4chan.org` and `boards.4channel.org`.
Clients MUST send no more than one request per second, MUST set thread-polling intervals to at least 10 seconds (preferably higher), and SHOULD use `If-Modified-Since` so that unchanged threads return `304 Not Modified`.'
version: '2026-05-28'
termsOfService: https://github.com/4chan/4chan-API#api-terms-of-service
contact:
name: 4chan API
email: api@4chan.org
url: https://github.com/4chan/4chan-API
license:
name: 4chan API Terms of Service
url: https://github.com/4chan/4chan-API#api-terms-of-service
x-generated-from: documentation
x-source-url: https://github.com/4chan/4chan-API
x-last-validated: '2026-05-28'
servers:
- url: https://a.4cdn.org
description: Production 4chan read-only JSON API (HTTPS).
- url: http://a.4cdn.org
description: Production 4chan read-only JSON API (HTTP, legacy clients only).
tags:
- name: Catalog
description: Per-board catalog snapshot containing every OP and its preview replies, grouped by index page.
paths:
/{board}/catalog.json:
get:
operationId: getBoardCatalog
summary: 4chan Get Board Catalog
description: 'Returns the full catalog snapshot for the given board: every OP with its attributes and a short list of preview replies, grouped by index page. This is the largest per-board document and mirrors the public catalog page at `boards.4channel.org/{board}/catalog`.'
tags:
- Catalog
parameters:
- $ref: '#/components/parameters/BoardPath'
responses:
'200':
description: Successful response. Returns the catalog as an array of pages.
content:
application/json:
schema:
$ref: '#/components/schemas/CatalogResponse'
examples:
GetBoardCatalog200Example:
summary: Default getBoardCatalog 200 response
x-microcks-default: true
value:
- page: 1
threads:
- false: 570368
sticky: 1
closed: 1
now: 12/31/18(Mon)17:05:48
name: Anonymous
sub: Welcome to /po/!
com: Welcome to /po/! We specialize in origami, papercraft, and everything that's relevant to paper engineering.
filename: yotsuba_folding
ext: .png
w: 530
h: 449
tn_w: 250
tn_h: 211
tim: 1546293948883
time: 1546293948
md5: uZUeZeB14FVR+Mc2ScHvVA==
fsize: 516657
resto: 0
capcode: mod
semantic_url: welcome-to-po
replies: 2
images: 2
omitted_posts: 0
omitted_images: 0
last_replies:
- false: 570371
now: 12/31/18(Mon)17:21:29
name: Anonymous
com: FAQ reply.
time: 1546294889
resto: 570368
last_modified: 1546294897
'304':
description: Not Modified.
'404':
description: Board not found.
'503':
description: Service Unavailable.
x-microcks-operation:
delay: 0
dispatcher: FALLBACK
components:
schemas:
Post:
type: object
description: A single post — either an OP (when `resto == 0`) or a reply (when `resto` is the OP id). Many fields appear only on OPs (`replies`, `images`, `sticky`, `closed`, `archived`, …) or only on posts with an attached file.
required:
- 'no'
- resto
- now
- time
- name
properties:
'no':
type: integer
description: Numeric post ID.
example: 570368
resto:
type: integer
description: For replies, the OP ID this post replies to. For OPs, `0`.
example: 0
sticky:
type: integer
description: '`1` if the thread is pinned to the top of the board (OP only).'
enum:
- 0
- 1
example: 1
closed:
type: integer
description: '`1` if the thread is closed to new replies (OP only).'
enum:
- 0
- 1
example: 1
now:
type: string
description: Localized post timestamp in `MM/DD/YY(Day)HH:MM` (or `HH:MM:SS`) format, EST/EDT.
example: 12/31/18(Mon)17:05:48
time:
type: integer
description: UNIX timestamp the post was created.
example: 1546293948
name:
type: string
description: Display name used for the post (defaults to `Anonymous`).
example: Anonymous
trip:
type: string
description: User tripcode in the form `!tripcode` or `!!securetripcode`.
example: '!K.WeEabc'
id:
type: string
description: Poster ID (8 chars) — present only when the board has per-thread poster IDs enabled.
example: ABcd1234
capcode:
type: string
description: Staff capcode on the post.
enum:
- mod
- admin
- admin_highlight
- manager
- developer
- founder
example: mod
country:
type: string
description: ISO 3166-1 alpha-2 country code of the poster, or `XX` if unknown.
example: US
country_name:
type: string
description: Human-readable country name of the poster.
example: United States
board_flag:
type: string
description: Board-specific flag code (only on boards with board flags enabled).
example: AB
flag_name:
type: string
description: Board-specific flag display name.
example: Flag Name AB
sub:
type: string
description: OP subject (OP only, when set).
example: Welcome to /po/!
com:
type: string
description: Post comment as HTML-escaped string.
example: Welcome to /po/! We specialize in origami, papercraft, and everything that's relevant to paper engineering.
tim:
type: integer
description: UNIX timestamp + microtime that the attachment was uploaded — also the file ID for `i.4cdn.org`.
example: 1546293948883
filename:
type: string
description: Original filename of the attachment as uploaded.
example: yotsuba_folding
ext:
type: string
description: Attachment file extension.
enum:
- .jpg
- .png
- .gif
- .pdf
- .swf
- .webm
example: .png
fsize:
type: integer
description: Attachment file size, in bytes.
example: 516657
md5:
type: string
description: 24-character packed base64 MD5 hash of the attachment.
example: uZUeZeB14FVR+Mc2ScHvVA==
w:
type: integer
description: Attachment width in pixels.
example: 530
h:
type: integer
description: Attachment height in pixels.
example: 449
tn_w:
type: integer
description: Thumbnail width in pixels.
example: 250
tn_h:
type: integer
description: Thumbnail height in pixels.
example: 211
filedeleted:
type: integer
description: '`1` if the post had a file and that file has been deleted.'
enum:
- 0
- 1
example: 0
spoiler:
type: integer
description: '`1` if the attachment is spoilered.'
enum:
- 0
- 1
example: 0
custom_spoiler:
type: integer
description: Custom spoiler ID `1-10` (only on boards with custom spoilers).
minimum: 1
maximum: 10
example: 1
replies:
type: integer
description: Total number of replies in the thread (OP only).
example: 2
images:
type: integer
description: Total number of image replies in the thread (OP only).
example: 2
bumplimit:
type: integer
description: '`1` once the thread has reached its bump limit (OP only).'
enum:
- 0
- 1
example: 0
imagelimit:
type: integer
description: '`1` once the thread has reached its image-reply limit (OP only).'
enum:
- 0
- 1
example: 0
tag:
type: string
description: Category of `.swf` upload on `/f/` (OP only, `/f/` only).
example: Game
semantic_url:
type: string
description: SEO-friendly URL slug for the thread (OP only).
example: welcome-to-po
since4pass:
type: integer
description: Year the poster bought a 4chan Pass (only when the poster opted in).
example: 2018
unique_ips:
type: integer
description: Number of unique posters in the thread (OP only, only when the thread is live).
example: 1
m_img:
type: integer
description: '`1` if a mobile-optimized variant of the attachment exists.'
enum:
- 0
- 1
example: 1
archived:
type: integer
description: '`1` once the thread has been archived (OP only).'
enum:
- 0
- 1
example: 1
archived_on:
type: integer
description: UNIX timestamp the thread was archived (OP only).
example: 1566530948
omitted_posts:
type: integer
description: Replies omitted from a catalog/index preview (OP only on catalog/index responses).
example: 1
omitted_images:
type: integer
description: Image replies omitted from a catalog/index preview (OP only on catalog/index responses).
example: 1
last_modified:
type: integer
description: UNIX timestamp the thread was last modified (OP only on catalog/threadlist responses).
example: 1566530948
last_replies:
type: array
description: Most recent reply objects shown in a catalog preview (OP only on catalog responses).
items:
$ref: '#/components/schemas/Post'
CatalogPage:
type: object
description: One index page in a catalog response.
required:
- page
- threads
properties:
page:
type: integer
description: Index page number this catalog page entry belongs to.
example: 1
threads:
type: array
description: Catalog thread entries (each is an OP `Post` object enriched with `last_replies`).
items:
$ref: '#/components/schemas/Post'
CatalogResponse:
type: array
description: Top-level response from `/{board}/catalog.json` — an array of pages, each containing OP threads with preview replies.
items:
$ref: '#/components/schemas/CatalogPage'
parameters:
BoardPath:
name: board
in: path
required: true
description: Board directory short name (e.g. `a`, `b`, `g`, `pol`, `po`, `v`). The full list of valid values is the `board` field on each entry in `/boards.json`.
schema:
type: string
pattern: ^[a-z0-9]+$
minLength: 1
maxLength: 8
example: po
example: po