# Envoy Proxy External Processing API

**Canonical:** https://apis.io/apis/envoy-proxy/external-processing-api/  
**Provider:** Envoy Proxy — https://apis.io/providers/envoy-proxy/  
**Documentation:** https://www.envoyproxy.io/docs/envoy/latest/configuration/http/http_filters/ext_proc_filter

Envoy Proxy External Processing API is one of 25 APIs that [Envoy Proxy](https://apis.io/providers/envoy-proxy/) publishes on the [APIs.io](https://apis.io/) network. Tagged areas include Extensibility, gRPC, Proxies, and Request Processing. The published artifact set on APIs.io includes API documentation, an API reference, and a GitHub repository.

The Envoy External Processing API is a gRPC-based service that enables an external server to inspect and modify HTTP requests and responses as they pass through Envoy. This extensibility mechanism supports use cases such as custom authentication, header manipulation, body transformation, and dynamic routing decisions without requiring Envoy filter plugins.

## Machine-readable artifacts (3)

- **Documentation** — https://www.envoyproxy.io/docs/envoy/latest/configuration/http/http_filters/ext_proc_filter
- **Reference** — https://www.envoyproxy.io/docs/envoy/latest/api-v3/service/ext_proc/v3/external_processor.proto
- **GitHubRepository** — https://github.com/envoyproxy/envoy

## Other Envoy Proxy APIs (12)

- [Envoy Proxy Rate Limit Service API](https://apis.io/apis/envoy-proxy/rate-limit-service-api/)
- [Envoy Proxy Health Discovery Service API](https://apis.io/apis/envoy-proxy/health-discovery-service-api/)
- [Envoy Proxy gRPC Access Log Service API](https://apis.io/apis/envoy-proxy/access-log-service-api/)
- [Envoy Proxy External Authorization API](https://apis.io/apis/envoy-proxy/external-authorization-api/)
- [Envoy Proxy Metrics Service API](https://apis.io/apis/envoy-proxy/metrics-service-api/)
- [Envoy Proxy Tap Service API](https://apis.io/apis/envoy-proxy/tap-service-api/)
- [Envoy Proxy Certificates API](https://apis.io/apis/envoy-proxy/envoy-proxy-certificates-api/)
- [Envoy Proxy Cluster Discovery API](https://apis.io/apis/envoy-proxy/envoy-proxy-cluster-discovery-api/)
- [Envoy Proxy Clusters API](https://apis.io/apis/envoy-proxy/envoy-proxy-clusters-api/)
- [Envoy Proxy Configuration API](https://apis.io/apis/envoy-proxy/envoy-proxy-configuration-api/)
- [Envoy Proxy Debugging API](https://apis.io/apis/envoy-proxy/envoy-proxy-debugging-api/)
- [Envoy Proxy Endpoint Discovery API](https://apis.io/apis/envoy-proxy/envoy-proxy-endpoint-discovery-api/)

## Tags

Extensibility, gRPC, Proxies, Request Processing

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/apis/envoy-proxy/external-processing-api/). The API's provider profile, Kin Score and agent-readiness rating are at https://apis.io/providers/envoy-proxy/.