Getting Started

Introduction

Start with the provider and strategy that match your workload, then scale without changing your mental model.

Trypema is a sliding-window rate limiting library for Rust with three providers and two strategies:

Three paper-craft rate-limiter topologies showing local state, direct shared Redis state, and local state synchronized to Redis. — Local keeps state in one process; Redis centralizes every call; hybrid periodically synchronizes local state to Redis.

Provider	Best for	Main trade-off
Local	single-process services, jobs, CLIs	state is not shared
Redis	shared limits across many instances	every check performs Redis I/O
Hybrid	very high-throughput distributed APIs	decisions can lag by its configured Redis flush interval (`SyncInterval`)

Strategy	Best for	Behavior
Absolute	hard admission control	allow or reject
Suppressed	graceful degradation	probabilistic shedding near or above the limit

What Trypema is good at

Starting local and keeping one consistent model as deployment grows.
Using fractional rates such as 0.5 or 5.5 requests per second.
Running best-effort distributed limiting with Redis 7.2+.
Choosing between allow/reject admission and smoother traffic shedding.

What to keep in mind

Local state is process-local.
Redis and hybrid are best-effort distributed limiters, not strictly linearizable admission control.
redis-tokio and redis-smol are mutually exclusive.

Trypema comes from the Koine Greek word "τρυπήματος" (trypematos), "hole" or "opening," from the biblical phrase "through the eye of a needle." The image fits the library well: a rate limiter is a narrow gate that controls what passes through.

Introduction

What Trypema is good at

What to keep in mind

The name

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