Skip to content

features.md

Latest commit

 

History

History
70 lines (52 loc) · 10 KB

features.md

File metadata and controls

70 lines (52 loc) · 10 KB
Raw

sbproxy Features Hub

Last modified: 2026-08-28

This page used to be a five-domain tour of the binary. That tour duplicated api-gateway.md, ai-gateway.md, mcp-and-agents.md, a2a-gateway.md, and policy.md, and it went stale whenever one of those pages moved. Start from the walkthrough that matches the traffic you have, then use the catalogs below when you need every action: or policies: type in one list.

Start here

You want Page
API + MCP + AI on one listener all-traffic-gateway.md
Apps calling models getting-started-ai-estate.md
Agents and crawlers calling you getting-started-inbound.md
A model you run locally quickstart-serve.md

Domain hubs: api-gateway.md, ai-gateway.md and providers.md, mcp-and-agents.md, a2a-gateway.md, policy.md, scripting.md, architecture.md. Field tables: configuration.md.

The rest of this page is the action, policy, and scripting catalogs inbound links still point at. They will move next to those hubs; until they do, this is the address.

6. Reference: every action type

An origin's action: decides what serves the request, and forward rules can pick a different action per matched rule. These seventeen types are the complete set the config compiler accepts, mirrored from its dispatch table; any other type: string is a linked plugin, an extension-bundle hook, or a config error. architecture.md shows where dispatch happens in the pipeline; request-flow.md walks everything around it.

  • proxy reverse-proxies to a single upstream URL. It carries the classic knobs: base-path stripping, query preservation, Host and SNI overrides, forwarding-header controls, retries with backoff, DNS-based service discovery for upstreams whose IPs churn, and IP pinning for reaching a backend without traversing its public CDN entry. Docs: routing.md, configuration.md.
  • load_balancer spreads traffic across a target pool: eight algorithms (round-robin, weighted random, least connections, IP/URI/header/cookie hash, and ketama-style ring_hash), five named custom strategies (first-healthy, gpu-aware, lora, lora-aware, bandit), three health layers (active probes, passive outlier ejection, per-target circuit breakers), and blue-green and canary deployment modes with backup targets and priority tiers. Docs: routing.md, routing-strategies.md.
  • static serves a fixed response straight from config: status, body, content type, extra headers. Maintenance pages, stubs, well-known files.
  • redirect issues HTTP redirects (301, 302, 307, 308), including bulk source-to-destination lists compiled at load time into an O(1) path lookup. Docs: bulk-redirects.md.
  • echo reflects the request back as JSON: method, path, headers, body. The debugging and smoke-test action.
  • mock returns a configured JSON document, for standing up an API's shape before the real upstream exists.
  • beacon answers with a one-pixel transparent GIF, so an analytics or tracking pixel needs no upstream at all.
  • noop accepts the request and returns an empty 200. A placeholder for scaffolding a config before its real action lands.
  • websocket proxies WebSocket upgrades, with subprotocol negotiation, message-size limits, and host override; auth and policies run before the upgrade like on any other action. Docs: websocket.md.
  • grpc passes gRPC through on HTTP/2 for every RPC cardinality, unary through bidirectional streaming, with opt-in gRPC-Web translation for browser clients and descriptor-driven REST-to-gRPC transcoding routes. Both translation modes are unary or server-streaming only, and a body-reading policy on the origin stalls streaming calls. Docs: grpc.md, routing.md.
  • graphql proxies GraphQL with a query-depth cap, an introspection toggle, and optional query validation before anything reaches the upstream. Docs: graphql.md.
  • storage serves objects from S3, Google Cloud Storage, Azure Blob, or a local directory. Example: Storage Action.
  • ai_proxy is the AI gateway in one action: the OpenAI-compatible surface, the provider catalog, model aliases, LLM-aware routing, guardrails, budgets, semantic caching, and local model hosting. ai-gateway.md is the reference; providers.md is the catalog.
  • mcp is the MCP gateway: federates real MCP servers, OpenAPI-derived tools, and config-defined local tools behind one endpoint, with RBAC, tool versioning, quotas, and content filters. mcp.md and mcp-compose.md are the references. Cedar on tools/call: cedar-policy.md.
  • a2a proxies agent-to-agent JSON-RPC with envelope trust rules, delegation-depth caps, cycle detection, and caller and callee lists. Docs: a2a-gateway.md.
  • abtest splits traffic across weighted backend variants for an A/B test. A first request takes a weighted roll and gets a sticky cookie back; every request after it that returns the cookie reaches the same variant. Docs: configuration.md, example: A/B Test Routing.
  • https_proxy is a guarded TLS reverse-proxy relay to the request's resolved host rather than a URL fixed in config, allow-listed by allowed_hosts. It is not an HTTP CONNECT tunnel. The narrow case: a wildcard origin that wants to relay only a named subset of the hosts it would otherwise match. Docs: configuration.md, example: HTTPS Relay.

7. Reference: every policy type

policy.md is the catalog, with a one-line job description for each of the thirty policies: types and a link to its full documentation. The names, grouped by the job you are hiring for:

  • Rate, volume, and budget: rate_limiting, rate_limit_budget, concurrent_limit, request_limit, ddos, ip_filter, agent_budget.
  • Identity and access: object_authz (BOLA and BFLA enforcement, plus enumeration detection), agent_class, a2a, csrf, security_headers.
  • Content, validation, and DLP: request_validator, openapi_validation, body_threat_protection, waf, http_framing, sri, content_digest, page_shield, dlp, exposed_credentials.
  • AI-specific: ai_crawl_control, prompt_injection_v2, semantic_constraint.
  • Enrichment: geoip, user_agent_parser. Neither denies traffic; both annotate the request for downstream identity/anomaly hooks and, optionally, the upstream request. Docs: request-enrichment.md.
  • Scripting-driven: expression (CEL), rego, assertion.
  • Packs: owasp_api_top10 is not a twenty-ninth type. The compiler expands it into entries from the groups above, backs off per item when you author the type yourself, and reports each of the ten items in a five-state manifest, including the ones it does not cover. Docs: owasp-api-top10.md.

Authentication is a separate axis, configured on an origin's auth: block rather than in policies:: api_key, basic_auth, bearer, jwt, digest, forward_auth, ldap_auth, oidc, bot_auth (Web Bot Auth), and cap, plus mTLS client verification at the listener. Chooser: authentication.md. Digest example: examples/auth-digest/.

8. Reference: where custom logic attaches

Five engines run operator-supplied logic, all loaded from config and all hot-reloadable. The per-site contract (what the script receives, what it may return, the sandbox limits) is in scripting.md; the pipeline placement of every attachment point is in request-flow.md.

Engine Available at
CEL expression and assertion policies; rate-limit bucket keys and WAF persistent-block keys; forward-rule when: predicates; access-log custom fields; the cel response transform; the AI policy plane (ai_policy.expression); MCP argument and result policies; MCP local-tool step conditions
Rego rego policies; request and response modifiers; MCP argument and result policies; extension-bundle policy hooks with runtime: rego
Lua Request and response modifiers (returned headers); lua raw-body and lua_json transforms; WAF custom rules; access-log custom fields; response-cache key and admit events; MCP local-tool response shaping
JavaScript Request and response modifiers (returned headers); javascript and js_json transforms; WAF custom rules; access-log custom fields; response-cache key and admit events; extension bundles (JS or TypeScript); MCP tool-version adapters; MCP local-tool response shaping
WASM The wasm body transform (WASI preview 1, with opt-in per-request context); envelope-WASM extension-bundle hooks, including ai_routing; Proxy-Wasm HTTP filter chains via origins.<host>.filters[]

Beyond inline scripts, an extension bundle packages logic as a versioned directory (JavaScript, TypeScript, or compiled WASM) loaded from disk or from a digest-pinned git source, with no rebuild and no partial loads: auth, policy, action, and transform hooks in the core pipeline, plus AI guardrail, tool-call, and routing hooks, Proxy-Wasm streaming filters, and payment lifecycle hooks. plugins.md is the map of all of it; extension-bundles.md is the reference. Organizations that build their own binary can also compile logic in directly; that path and its costs are covered in plugins.md and architecture.md.