Cataas
Cataas (Cat as a Service) is a free, open-source REST API that returns random cat images and GIFs with optional tags, filters, sizing, and text overlays. The service is widely embedded in tutorials, demos, README files, and chat applications as a friction-free image source. The canonical implementation lives at github.com/cataas/cataas and runs at cataas.com.
Limited machine-readable signal and partial portal coverage — documentation a human can read, but little a machine or agent can consume without scraping.
API Evangelist profiles Cataas the way a machine reads it — 41 machine-readable artifacts across 4 APIs, pulled from the provider's own public surface and indexed so a developer, an analyst, or an AI agent can evaluate it against every other provider on the network.
Every provider in the network is reduced to the same set of machine-readable artifacts — OpenAPI contracts, event specifications, GraphQL schemas, runnable collections, pricing and rate-limit signals, security posture, OAuth scopes, and the agent surfaces (MCP servers and skills) that let software drive the API on its own. We profile them because the interface is the part of a company you can actually inspect: it is a truer signal of what a provider does than any marketing page. From those artifacts we compute the Kin Score — Cataas scores 41.8/100 (thin), with a separate agent-readiness read of 41/100 (agent aware). The full breakdown is below, followed by every artifact we hold — each card links through to its machine-readable definition on apis.io.
Kin Score
This is the API Evangelist rating — a single, repeatable read computed from the artifacts on this page. Green fill is points earned; the red track is points possible, so every bar shows earned-versus-possible at a glance.
Kin Score
How this is scored →scored 2026-07-27 · rubric v0.5
How we profile Cataas
Each block below is one kind of artifact we hold for Cataas. For each we say what it is and why it earns a place in the profile, then list every one we've indexed — capped at two rows, scroll within the panel for the rest.
APIs 4
Each API is captured as its own OpenAPI definition — every operation, parameter, and response. This is the single most useful machine-readable description of what an API does, and it's what lets us score, lint, mock, and generate against it without asking the provider for anything.
Individual APIs this provider publishes, each with its own machine-readable definition.
Cataas Admin API
Administrative operations on the cat catalog (admin token required)
Cataas Catalog API
Browse cats, tags, and stats programmatically (JSON)
Cataas Cats API
Random and tagged cat image retrieval
Cataas Upload API
Submit a cat image (rate-limited / moderated)
Features 9
The notable capabilities this provider advertises, captured as structured features so they can be searched and compared instead of read one landing page at a time.
Notable capabilities this provider offers.
Random Cat Image
GET /cat returns a random cat image (JPEG, PNG, or GIF).
Tagged Cat Retrieval
GET /cat/{tag} returns a random cat matching one or more comma-separated tags.
Animated GIFs
GET /cat/gif returns a random animated cat.
Text Overlay
GET /cat/says/{text} renders user-supplied text on top of a random cat with configurable font size, color, and background.
Image Filters
filter=blur|mono|negate|custom with per-channel and per-property tuning (brightness, hue, saturation, RGB).
Sizing and Cropping
type, width, height, fit, and position query parameters resize and crop the returned image.
JSON Catalog API
/api/cats, /api/tags, /api/count expose the catalog programmatically.
Content Negotiation
json=true returns a metadata document instead of binary; html=true returns an embedding wrapper page.
Free and Unauthenticated
All read endpoints are public and require no API key.
Scroll within the panel for all 9 ·
Semantic Vocabularies 1
JSON-LD contexts give the data shared meaning across APIs. We profile them because semantics are what let a machine reconcile 'customer' here with 'customer' somewhere else.
JSON-LD contexts and semantic vocabularies used across these APIs.
Cataas Context
JSON-LDSpectral Rules 2
Governance rulesets we run against this provider's specs — the automated checks behind parts of the score. Profiling them makes the quality bar explicit and re-runnable, not a matter of opinion.
Cataas API Rules
SPECTRALCataas API Rules
SPECTRALJSON Schema 4
Standalone JSON Schema definitions describe the data models behind the API. We profile them so the shapes are validatable on their own — useful long after a single request is forgotten.
Standalone JSON Schema definitions for this provider's data models.
JSON Structure 4
JSON Structure captures the data shapes in a form built for tooling — a complement to JSON Schema that keeps the model machine-legible.
JSON Structure definitions describing this provider's data shapes.
Cat Structure
JSON STRUCTURECount Response Structure
JSON STRUCTUREEdit Cat Request Structure
JSON STRUCTUREUpload Cat Request Structure
JSON STRUCTUREExamples 4
Real request and response payloads are what turn a spec from abstract into obvious — and they're one of the twelve things an agent needs to call an API correctly on the first try.
Example request and response payloads for these APIs.
Cat Example
EXAMPLECount Response Example
EXAMPLEEdit Cat Request Example
EXAMPLEUpload Cat Request Example
EXAMPLESecurity Posture 2
Authentication, domain security, vulnerability disclosure, and trust-center signals — the evidence that a provider takes security seriously enough to document it. We profile it because you can't govern what you can't see.
Authentication, domain security, vulnerability disclosure, and trust-center signals.
Agentic Access 1
An x-agentic-access contract marks which operations are safe for an agent to run on its own and which need a human in the loop. It is the difference between an API an agent can use and one it can use safely.
Recommended x-agentic-access execution contracts for AI agents.
Use Cases 5
What developers actually build with this provider — captured so the catalogue answers 'what is this for', not just 'what does this expose'.
What developers build with this provider.
Tutorials and Demos
Embed live cat images in API tutorials, learn-to-code lessons, and conference demos.
README Decoration
Decorate open-source READMEs and personal sites with rotating cat imagery.
Chat Bots and Slash Commands
Slack, Discord, and Teams bots fetch random cats on demand via /cat or /cat/says.
Mocking Image-Heavy APIs
Stand in for a real image-CDN-backed API while prototyping front-end layouts.
Image Pipeline Testing
Exercise resize, format-conversion, and filtering pipelines with predictable image input.
Integrations 4
Pre-built integrations with other platforms tell you where this provider already fits in a stack.
Pre-built integrations with other platforms and tools.
Slack
Official slack-command repo wires /cat into Slack workspaces.
Discord
Official discord-bot repo provides a Cataas Discord integration.
Pipeworx MCP Gateway
Community MCP server (pipeworx-io/mcp-cataas) wraps the API for use by Claude and other MCP clients.
Public APIs Catalog
Listed in the public-apis/public-apis Animals category.
Solutions 1
Packaged solutions the provider offers on top of the raw API surface.
Packaged solutions this provider offers.
Self-Hosted Catalog
Run your own Cataas instance from cataas/cataas (Node.js + MongoDB + sharp) to power internal demos or branded image services.
Resources
Every other property we hold for Cataas — documentation, portals, status pages, policies, and corporate surface — grouped by the job it does, following the integrator's arc from getting started to running in production.
Agent Surfaces 1
MCP servers, agent skills, and machine-readable catalogs
Design & Contract 3
Pagination, idempotency, versioning, errors, and events
Build 6
SDKs, sample code, and the tooling you integrate with
Access & Security 2
Authentication, authorization, and security posture
Company 1
The organization behind the API
Other 1
Properties that don't map to a standard resource type
← All providers · Data indexed from github.com/api-evangelist/cataas · machine-readable index on apis.io