Abacus

About Abacus

Abacus is a free HTTP API for creating and incrementing numeric counters, intended for use cases such as tracking page views or button clicks on a website. Counters are organized by namespace and key, with the namespace typically set to the requesting site's domain to avoid collisions; counters are unlisted, meaning they are accessible only to those who know the namespace and key. The API is accessed via simple GET requests (e.g., a /hit endpoint that increments and returns a counter's value), supports JSONP and CORS, and can render a counter's value as an SVG badge/shield with configurable colors, style, font, and text.

The API also provides endpoints to retrieve a counter's current value, check service health/uptime, and create, delete, set, or reset counters, with administrative actions requiring an admin key issued at counter creation. Data is stored using Valkey. Usage is rate-limited to 30 requests per IP address per 10-second window, with rate-limit status communicated via response headers and a 429 error when the limit is exceeded.

This service is suited for developers who want a lightweight, no-cost way to add simple visit or event counters to websites or applications without building their own counting backend.

Key features

• Create and increment simple numeric counters via a hit endpoint
• Retrieve current counter values via a get endpoint
• Namespace-based key organization to avoid name collisions
• Generate SVG shield badges displaying counter values with customizable colors, fonts, and styles
• Delete counters using an admin key
• JSONP, XHR, and CORS support for cross-origin requests

Frequently asked questions