About

Finding high-quality, random cat imagery for projects, placeholders, or simple amusement typically involves navigating cluttered stock photo sites or unreliable APIs. This generator pulls real photographs from multiple public cat image endpoints - primarily TheCatAPI and Cataas - with automatic failover if a source is unavailable. Each request returns a unique image at full resolution. The tool applies client-side Canvas pixel manipulation for filters (grayscale, sepia, brightness adjustments) rather than CSS-only effects, meaning the filtered version is what you actually download. Favorites persist in your browser via localStorage, so your collection survives page reloads. Note: image availability depends on upstream API uptime. Approximately 3 fallback sources are attempted per request before reporting failure.

Formulas

Image filter transformations are applied via direct pixel manipulation on an HTML Canvas. Each pixel is represented as a tuple of R, G, B, A values in the range [0, 255].

Grayscale conversion uses the luminance-weighted formula (ITU-R BT.601):

gray = 0.299 × R + 0.587 × G + 0.114 × B

Sepia tone applies a matrix transformation per pixel:

R_out = 0.393R + 0.769G + 0.189B
G_out = 0.349R + 0.686G + 0.168B
B_out = 0.272R + 0.534G + 0.131B

Brightness adjustment multiplies each channel by a factor b ∈ [0.0, 3.0]:

C_out = clamp(C_in × b, 0, 255)

Contrast uses the standard formula with factor f derived from contrast level c ∈ [−100, 100]:

f = 259 × (c + 255)255 × (259 − c)
C_out = clamp(f × (C_in − 128) + 128, 0, 255)

Where C represents any color channel (R, G, or B), and clamp restricts output to the valid byte range.

Reference Data

API Source	Base URL	Auth Required	Rate Limit	Avg Response	Image Format	Breed Filter	Resolution	CORS	Reliability
TheCatAPI	api.thecatapi.com	No (basic)	~10 req/min	~200ms	JPG/PNG/GIF	Yes (with key)	Variable (up to 4K)	Yes	High
Cataas	cataas.com	No	Unlimited	~400ms	JPG/PNG	No	Variable	Yes	Medium
PlaceKitten	placekitten.com	No	Unlimited	~150ms	JPG	No	Custom (param)	Yes	High
Lorem Flickr	loremflickr.com	No	Unlimited	~300ms	JPG	Tag-based	Custom (param)	Yes	Medium
Random Duck (comparison)	random-d.uk	No	Unlimited	~100ms	JPG/GIF	No	Variable	Yes	High
HTTP Cat	http.cat	No	Unlimited	~100ms	JPG	By HTTP code	Fixed	Yes	High
Cat Facts API	catfact.ninja	No	Unlimited	~80ms	Text only	N/A	N/A	Yes	High
TheDogAPI (comparison)	api.thedogapi.com	No (basic)	~10 req/min	~200ms	JPG/PNG	Yes	Variable	Yes	High
Unsplash Source	source.unsplash.com	No (deprecated)	~50 req/hr	~500ms	JPG	Tag search	Custom	Yes	Low
Pixabay API	pixabay.com/api	Yes (key)	~100 req/min	~300ms	JPG/PNG	Search	Up to 5K	Yes	High
Pexels API	api.pexels.com	Yes (key)	~200 req/hr	~250ms	JPG	Search	Up to 6K	Yes	High
AWS Random Cat	aws.random.cat	No	Unlimited	~350ms	JPG/GIF	No	Variable	Partial	Low

Frequently Asked Questions

The generator relies on external public APIs (TheCatAPI, Cataas, PlaceKitten). If an upstream server is down or rate-limiting your IP, the tool automatically attempts up to 3 fallback sources. Persistent failures typically indicate network restrictions (corporate firewalls, VPNs blocking external image hosts). The toast notification will indicate which source failed. Try again after a few seconds - most rate limits reset within 60 seconds.

Yes. Filters are applied via Canvas pixel manipulation at the original image resolution, not via CSS effects. The downloaded file contains the actual transformed pixel data. However, note that cross-origin restrictions may occasionally prevent Canvas access. When this occurs, the tool falls back to downloading the unfiltered original. The filename includes the filter name when successfully applied.

LocalStorage typically allows approximately 5 MB per origin. Each favorite entry stores a URL string (averaging ~120 bytes) plus metadata (~80 bytes). This yields roughly 25,000 favorites before hitting the limit. The tool monitors storage usage and warns at 90% capacity. Favorites are stored as JSON arrays and deduplicated by URL hash to prevent duplicates.

Each channel (R, G, B) is multiplied independently by the brightness factor and clamped to [0, 255]. This means at high brightness values, channels near 255 will clip before others, causing a shift toward the dominant remaining color. For example, a pixel at RGB(200, 100, 50) with brightness factor 2.0 becomes (255, 200, 100) - the red clips first. This matches standard image editor behavior (Photoshop, GIMP) but differs from perceptual brightness models.

TheCatAPI images are community-contributed and generally free for personal use. Cataas and PlaceKitten serve placeholder-style images without explicit commercial licenses. For commercial projects, verify the specific image source's terms. This tool does not claim or grant any licensing rights over the fetched images. When in doubt, use the image as a placeholder during development and replace with properly licensed assets for production.