Filter Reference

Built-in filters organized by protocol and category.

Praxis documentation version

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Built-in filters organized by protocol and category.

HTTP / Observability

Filter	Feature	Description
`access_log`	-	Logs structured access records for each request and response.
`cloud_events`	`cloud-events-filter`	Generate structured `CloudEvents` and ship them to a configured HTTP endpoint.
`request_id`	-	Ensures every request carries a correlation ID.
`trace_context`	-	Propagates W3C Trace Context and `x-request-id` correlation.

HTTP / Payload Processing

Filter	Feature	Description
`compression`	-	Enables Pingora’s built-in response compression when present in a filter chain.
`grpc_web`	-	Translates gRPC-Web calls to native gRPC and back.
`json_body`	-	Rewrites JSON request bodies with JSON Pointer add, remove, replace, and extract, and response bodies with remove and extract.
`json_body_field`	-	Extracts top-level fields from a JSON request body and promotes their values to request headers using [`StreamBuffer`] mode.
`json_rpc`	-	Extracts JSON-RPC 2.0 envelope metadata from request bodies and promotes method, id, and kind to request headers and filter results for routing.

HTTP / Security

Filter	Feature	Description
`basic_auth`	`basic-auth-filter`	HTTP Basic Authentication filter (RFC 7617).
`cors`	-	Spec-compliant CORS filter implementing origin validation, preflight handling, and response header injection.
`credential_injection`	-	Injects per-cluster API credentials into upstream requests.
`csrf`	-	CSRF protection filter that validates request origins against a trusted allowlist.
`forwarded_headers`	-	Injects `X-Forwarded-For`, `X-Forwarded-Proto`, and `X-Forwarded-Host` headers into upstream requests.
`guardrails`	-	Rejects requests matching string, regex, or PII rules against headers and/or body content.
`ip_acl`	-	IP-based access control filter.
`peer_identity_trust`	`spiffe`	Validates that the downstream mTLS peer identity matches a configured trusted peer before allowing the request to continue.
`policy`	`policy-engine`	Embeds the Praxis Policy Engine in-process to enforce multi-source identity, APL route policy, RFC 8693 token exchange, field redaction, session taint, audit emission, and (under `body_access: read_write`) request / response body rewriting. Content scanning is a host plugin the engine dispatches, not a bundled one.

HTTP / Traffic Management

Filter	Feature	Description
`circuit_breaker`	-	Rejects requests to clusters whose circuit is open.
`endpoint_selector`	-	Selects an upstream endpoint from a trusted mutation source.
`grpc_detection`	-	Detects the gRPC variant from the request `content-type` header and records it for branch-chain routing and observability.
`grpc_timeout`	-	Honours the `grpc-timeout` request header as a real deadline.
`head_classifier`	-	Classifies a request from its head and promotes the matched class as a reserved, client-unspoofable `x-praxis-head-class` header.
`iterative_request_router`	`iterative-request-router`	Framework-level filter for iterative sub-request execution.
`load_balancer`	-	Selects an upstream endpoint using the cluster’s configured strategy.
`rate_limit`	-	Token bucket rate limiter that rejects excess traffic with 429.
`redirect`	-	Returns a redirect response without contacting any upstream.
`router`	-	Routes requests to clusters based on path prefix and host header.
`static_response`	-	Returns a fixed response without contacting any upstream.
`sticky_sessions`	-	Sticky sessions HTTP filter.
`timeout`	-	Enforces a maximum end-to-end latency from request receipt to response headers.

HTTP / Transformation

Filter	Feature	Description
`grpc_status`	-	Answers proxy-generated errors in the shape gRPC clients expect.
`headers`	-	Adds, sets, or removes headers on upstream requests and downstream responses.
`path_rewrite`	-	Rewrites the request path before forwarding to the upstream.
`url_rewrite`	-	Rewrites request URLs using regex substitution and query parameter manipulation before the request reaches upstream.

TCP / Observability

Filter	Feature	Description
`tcp_access_log`	-	Logs TCP connection events.

TCP / Traffic Management

Filter	Feature	Description
`sni_router`	-	Routes TCP connections by SNI hostname.
`tcp_load_balancer`	-	Selects an upstream TCP endpoint using the cluster’s configured strategy.