4chan (4chan)

4chan is a simple image-based bulletin board where anyone can post comments and share images across topic-specific boards. 4chan exposes a read-only JSON API (launched September 2012) that serves the same board, thread, catalog, and archive data consumed by the public site via static JSON files at a.4cdn.org. The API supports GET/HEAD/OPTIONS only — there is no posting, authentication, or write surface.

URL: Visit APIs.json URL

Run: Capabilities Using Naftiko

Tags:

• Social, Bulletin Board, Imageboard, Read Only, JSON, Public APIs, Community

Timestamps

• Created: 2026-05-28
• Modified: 2026-05-28

APIs

4chan Read-Only JSON API

Read-only HTTP JSON API serving boards.json, threads.json, catalog.json, archive.json, board index pages, and individual thread documents from a.4cdn.org. Mirrors the data visible at boards.4chan.org / boards.4channel.org. No authentication, no write operations. CORS allowed only from boards.4chan.org and boards.4channel.org origins.

Human URL: https://github.com/4chan/4chan-API

Tags:

• Social, Imageboard, Read Only

Properties

• Documentation
• OpenAPI
• SignUp
• Support
• TermsOfService
• NaftikoCapability
• NaftikoCapability
• NaftikoCapability
• NaftikoCapability
• NaftikoCapability
• NaftikoCapability

Common Properties

• Website
• Documentation
• GitHubOrganization
• SourceCode — 4chan native browser extension source
• ContactEmail
• Tools — MCP Server (community, unofficial)
• SDK — Python Wrapper (BASC-py4chan, community)
• SDK — Python Wrapper (py-4chan, community)
• SDK — Node.js Client (4chanjs, community)
• SDK — Go Client (go-4chan-api, community)
• SDK — Rust Client (rchan, community)
• SDK — Racket Client (yotsubAPI, community)
• Tools — BA Thread Archiver (community)
• PublicAPIsListing
• Plans
• RateLimits
• Vocabulary
• SpectralRules
• JSONLD

Features

Name	Description
Read-Only JSON Catalog	Static JSON representations of boards, threads, catalogs, and archives are served from a.4cdn.org; clients use standard HTTP semantics including If-Modified-Since for caching.
No Authentication	The API requires no API key, no token, and no account; it is fully anonymous and serves the same data visible to anonymous web visitors.
HTTP Caching Built In	The API requires clients to send If-Modified-Since headers on repeated requests, allowing 304 Not Modified responses and reducing server load.
CORS Restricted to 4chan Origins	CORS is enabled but only for origins boards.4chan.org and boards.4channel.org via HTTP or HTTPS; only GET/OPTIONS/HEAD methods are accepted.
Per-Board Catalog	Every board (a, b, g, pol, po, etc.) exposes catalog, threadlist, archive, and per-page index endpoints with the same shape, making bulk crawling trivial.
Static Media Domains	User-uploaded images and thumbnails live at i.4cdn.org/{board}/{tim}.{ext}; static site assets including flags, spoiler images, and capcode icons live at s.4cdn.org.

Use Cases

Name	Description
Read-Only Board Crawlers	Build research crawlers that periodically snapshot board catalogs, threads, and archives while respecting the 1 request per second limit and 10 second per-thread refresh floor.
Thread Archivers	Mirror archived threads and their attached media to durable storage for academic study or cultural preservation (see BA Thread Archiver, Ayase / Asagi).
Imageboard Analytics	Use threads.json and catalog.json to chart posting volume, reply velocity, and moderator/admin capcode activity across boards over time.
Language Models and Markov Chains	Feed cleaned post comments from catalog.json and thread.json into text generation experiments (see 4chanMarkovText).
Static Site Mirrors	Combine boards.json + per-board catalog/thread JSON to build static site mirrors of individual threads suitable for read-only display.

Integrations

Name	Description
BASC-py4chan	Python wrapper providing Pythonic access to boards, threads, and posts.
4chanjs	Node.js and browser client for the 4chan JSON API.
go-4chan-api	Go client for crawling and consuming 4chan board JSON.
rchan	Rust crate exposing typed boards/threads/posts and a basic client.
Ayase / Asagi	Archive middleware that ingests 4chan JSON and stores posts in SQL for replay.
chan-mcp-server (community)	Unofficial Model Context Protocol server exposing 4chan boards/threads/catalog as MCP tools.

Solutions

Name	Description
Imageboard Research Archive	Combine threads.json polling with archive.json snapshots and i.4cdn.org media downloads to build a long-term archive that respects the published rate limits.
Capcode Activity Dashboard	Use catalog.json/thread.json capcode and id fields to surface moderator and admin activity per board over time.

Artifacts

Machine-readable API specifications organized by format.

OpenAPI

• 4chan Read-Only JSON API

JSON Schema

• Archive Response
• Board
• Boards Response
• Catalog Page
• Catalog Response
• Cooldowns
• Index Page Response
• Index Page Thread
• Post
• Thread Response
• Threadlist Entry
• Threadlist Page
• Threadlist Response

JSON Structure

• Archive Response
• Board
• Boards Response
• Catalog Page
• Catalog Response
• Cooldowns
• Index Page Response
• Index Page Thread
• Post
• Thread Response
• Threadlist Entry
• Threadlist Page
• Threadlist Response

JSON-LD

• 4chan Context

Examples

• Archive Response
• Board
• Boards Response
• Catalog Page
• Catalog Response
• Cooldowns
• Index Page Response
• Index Page Thread
• Post
• Thread Response
• Threadlist Entry
• Threadlist Page
• Threadlist Response

Capabilities

Naftiko capabilities organized one self-contained file per business surface (OpenAPI tag), each with both a REST adapter and an MCP adapter.

4chan Read-Only JSON API

Capability	Operations	File
Boards	1	capabilities/4chan-api-boards.yaml
Threadlist	1	capabilities/4chan-api-threadlist.yaml
Catalog	1	capabilities/4chan-api-catalog.yaml
Archive	1	capabilities/4chan-api-archive.yaml
Indexes	1	capabilities/4chan-api-indexes.yaml
Threads	1	capabilities/4chan-api-threads.yaml

Vocabulary

• 4chan Vocabulary — Unified taxonomy mapping 6 resources, 2 actions, 6 workflows, and 3 personas across operational (OpenAPI) and capability (Naftiko) dimensions

Rules

• 4chan Spectral Ruleset — 45 rules across 12 categories enforcing 4chan API conventions

Plans & Rate Limits

• 4chan Plans / Pricing — Free read-only JSON API; 4chan Pass documented for context only
• 4chan Rate Limits — 1 req/sec global, 10 seconds-per-thread polling floor, IP-scoped

Notes

The 4chan Read-Only JSON API was bulk-registered as part of a public-apis catalog sweep on 2026-05-28 and then enriched with a full OpenAPI 3.0.3 spec, Microcks-compatible inline examples, a Spectral ruleset, six per-tag Naftiko capabilities (REST + MCP), JSON Schema / JSON Structure / JSON-LD / example artifacts, a vocabulary, and API Commons Plans + Rate Limits documents — all generated from the official documentation at github.com/4chan/4chan-API.

Maintainers

FN: Kin Lane

Email: kin@apievangelist.com