guide

ExpressGateway — User Guide

Public, operator-facing documentation: how to configure, deploy, run, and operate ExpressGateway. New here? Start with the narrative guides below, then drop into the reference docs.

Guides (start here)

Doc	What it covers
overview.md	What ExpressGateway is, the problem it solves, where it fits, headline capabilities and the key limitations up front.
getting-started.md	Quickstart: build → pick an example config → run → serve a request → check metrics.
capabilities.md	The consolidated supported / gated / waived / deferred matrix — what works and what to know before you rely on it.
comparison.md	Factual positioning vs Envoy / Traefik / HAProxy / nginx, with honest tradeoffs.
PERFORMANCE.md	The S39 measured performance baseline, with its conditions and caveats.

Tasks & recipes

Doc	What it covers
cookbook.md	Complete, annotated configs for named scenarios — production HTTPS + HTTP/2, terminating gRPC, rolling out HTTP/3 via alt_svc, DoS hardening, QUIC Mode A — plus a combined-config capstone.
troubleshooting.md	First-run FAQ + symptom-indexed fixes: config rejected, won't boot, 502-to-everything, gRPC status missing, WebSocket on H2, cert reload, XDP attach.
deployment-patterns.md	Topology & scaling: stateless horizontal scale-out behind an external L4/L3 LB, SO_REUSEPORT handover, single-node / k8s patterns — and the HA it does not provide.
observability.md	What to actually monitor: golden signals, what healthy looks like, a starter Prometheus scrape + alert set.

Configuration & operation (reference)

Doc	What it covers
CONFIG.md	The full TOML configuration schema, reload semantics, worked examples.
DEPLOYMENT.md	Build-time prerequisites (cmake, clang, kernel floor), the systemd unit, capabilities, sysctls, the XDP toolchain caveat.
RUNBOOK.md	Operational procedures, every alert that can fire, the triage matrix, graceful-drain/restart.
METRICS.md	Every Prometheus metric family exported, the label-cardinality budget, scrape configuration.

Related (root + arch)

• ../../SECURITY.md — threat model, defenses, audit posture, disclosure policy.
• ../../CHANGELOG.md — release-notes-format changelog.
• ../features.md — the front×back protocol matrix + load-balancing reality (supported / gated / waived / deferred).
• ../known-limitations.md — bounded, documented operator-facing constraints (with who-it-affects).
• ../glossary.md — definitions of the terms used across these docs (Mode A/B, 9-cell, CID, Maglev, …).
• ../architecture.md — the developer crate map + crate-dependency graph.
• ../arch/ — developer/architecture documentation (incl. extending.md — how to extend the codebase).

Contributing

See the root CONTRIBUTING.md for how to build, test, and run the gates locally, and ../arch/DEV-SETUP.md for the detailed per-task box setup.