# Fairvisor vs. Envoy Rate Limiting

URL: https://fairvisor.com/compare/envoy-rate-limiting/

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 Fairvisor vs. Envoy Rate Limiting Compare Fairvisor with Envoy ext_authz flow The Situation Envoy rate limiting (lyft/ratelimit) is a proven pattern in Envoy-centric stacks, but it typically depends on external services and Redis.
Fairvisor provides in-process AI-aware enforcement with no Redis dependency on the request path.
Comparison Capability Fairvisor Envoy Rate Limit Service (lyft/ratelimit) Architecture In-process (OpenResty/LuaJIT) External gRPC service + Redis External dependencies None (MVP) Redis (required) Latency profile In-process decision path External call path (gateway -> service -> Redis) Limit keys JWT claims, headers, path, UA, combinations Headers, path from Envoy descriptors Cost-based budgets Yes No AI features Loop detection, token counting, circuit breaker, AI crawler detection No Staged actions Warn -> throttle -> reject Reject (binary) Shadow mode Yes No Management UI SaaS dashboard None (YAML config) Analytics Per-tenant dashboard, cost attribution Prometheus counters High availability In-process, no external SPOF in hot path Redis SPOF unless clustered When to Use Fairvisor You need AI-aware enforcement and cost-based budgets. You want to avoid Redis dependency on policy decisions. You want a management plane and richer analytics. When to Use Envoy Rate Limit Service You are deeply invested in Envoy/Istio descriptor patterns. You only need straightforward descriptor-based limits. Redis is already part of your accepted control stack. Use Them Together Envoy can continue handling core proxy routing. Fairvisor can provide advanced decisions via ext_authz. You can introduce AI-aware policies without replacing Envoy. Need more than descriptor + Redis rate limiting? Compare Fairvisor with Envoy ext_authz flow