Open source rate-limiter projects
Every project in the registry tagged rate-limiter, ranked by real GitHub adoption.
Resilience4j is a fault tolerance library designed for Java8 and functional programming
Secure, scalable API key management for developers
Rate limiting, caching, and request prioritization for modern workloads
Runtime security for AI apps and agents: prompt injection detection, tool-call authorization, sensitive-data redaction, bot protection, and rate limiting. Drop
Frequently asked questions
How many open source rate-limiter projects are there?
This registry tracks 4 projects tagged rate-limiter, with 17,713 GitHub stars between them. The most-adopted is resilience4j at 10,800 stars.
Are these rate-limiter projects free to use?
Yes — 3 of the 4 carry an explicit open-source licence across 1 distinct licence, so there is no licence fee. Where a project also sells a hosted or enterprise version, the self-hosted path remains free.
Which rate-limiter project should I choose?
The list above is ranked by GitHub stars, but stars measure attention rather than fit. Check three things on each card: the licence (permissive versus copyleft), the language it is written in, and the last-push date — a high-star project that has not been pushed in a year is a liability.
Are these rate-limiter projects still maintained?
3 of the 4 were pushed in the last 90 days, and every card shows its exact last-push date so you can see the rest. Sort your shortlist by that date before committing to a migration.