What Is Cat as a Service (CATAAS)?

Updated

CATAAS (Cat as a Service) is a REST API that returns cat images and GIFs on demand. You call a URL such as /cat and get a random cat back; you can add tags, overlaid text, filters, and size parameters to control what you get. It is useful when you need placeholder cat imagery for a demo, a test fixture, a chat bot, or a fun embed, and you want it without hosting images yourself. The site describes itself as "a REST API to spread peace and love (or not) thanks to cats."

What you can request

The API is organized around a small set of URL patterns. The table below reflects the endpoints listed in the site's documentation.

What you want URL pattern Example
Random cat /cat Random cat
Random cat with a tag /cat/:tag Random orange cute cat
Random GIF cat /cat/gif Random gif cat
Cat with overlaid text /cat/says/:text Random cat saying hello
Tagged cat with text /cat/:tag/says/:text Random cute cat saying hello
Text with font styling /cat/says/:text?fontSize=:size&fontColor=:color Custom random cat saying hello

Tags can be combined using the :tag separator, so a single request can narrow results to more than one tag.

Advanced options

Beyond tags and text, the documentation lists query parameters that change the image itself:

  • Type: /cat?type=:type accepts xsmall, small, medium, or square.
  • Filter: /cat?filter=:filter accepts blur, mono, negate, or custom.
  • Custom filter values: with filter=custom, you can pass brightness, lightness, saturation, and hue, or pass r, g, and b values.
  • Dimensions: /cat?width=:width or /cat?height=:height sets a custom size.
  • HTML output: /cat?html=true returns the cat inside an HTML page, which the docs note is useful for Twitter or Facebook embedded rendering.
  • JSON output: /cat?json=true returns a random cat as a JSON object.

Parameters can be combined. The documentation's own combo example is /cat/gif/says/Hello?filter=mono&fontColor=orange&fontSize=20&type=square.

Getting JSON data and tags

Two endpoints return data rather than an image:

  • /api/cats?tags=tag1,tag2&skip=0&limit=10 returns a list of cats, with tag filtering and paging via skip and limit.
  • /api/tags returns all available tags.

According to the site's changelog notes, JSON is returned when the request contains an application/json header, and tag search plus comma-separated tag combinations were fixed in the current major version. The API documentation is linked from the site as "API doc."

Things to know before you build on it

  • The homepage counter read "Have 0 cats for now" at the time of the captured page, so the available image pool may be limited or in flux; check /api/tags and /api/cats before relying on specific tags.
  • The site lists a "Buy me a beer" support link but no pricing page or payment details, so treat cost and usage limits as unspecified rather than free-for-any-volume.
  • The footer reads "© 2026 - Made with ❤️ by Kevin - all rights reserved," which is worth checking if you plan to redistribute the images rather than just display them.

For a quick start, request /cat to confirm the service responds, then add ?json=true if your client expects structured data, or move to /api/cats when you need a list rather than a single random image.