name: Spring Cloud Gateway Vocabulary
description: Domain vocabulary and taxonomy for Spring Cloud Gateway API gateway concepts, routing, filtering, and management.
version: "4.1.0"
created: "2026-05-02"
modified: "2026-05-02"
url: https://spring.io/projects/spring-cloud-gateway

terms:

  - term: Route
    definition: >-
      The fundamental building block of Spring Cloud Gateway, consisting of an ID, destination
      URI, a collection of predicates that must match for the route to apply, and a collection
      of filters applied to the request.
    category: Core Concept
    tags:
      - Routing
      - Configuration

  - term: Predicate
    definition: >-
      A Java 8 Function Predicate that evaluates a ServerWebExchange. Multiple predicates
      can be combined. Built-in predicates match on Path, Host, Method, Header, Query, Cookie,
      RemoteAddr, and Weight.
    category: Routing
    tags:
      - Matching
      - Condition

  - term: Filter
    definition: >-
      A GatewayFilter that can modify the inbound request or outbound response. Filters
      run in a defined order and include AddRequestHeader, RewritePath, CircuitBreaker,
      RequestRateLimiter, Retry, and many more built-in options.
    category: Request Processing
    tags:
      - Transformation
      - Middleware

  - term: Global Filter
    definition: >-
      A filter that applies to all routes without explicit configuration, handling cross-cutting
      concerns like load balancing, WebSocket routing, and request forwarding.
    category: Request Processing
    tags:
      - Cross-Cutting
      - Middleware

  - term: Route Predicate Factory
    definition: >-
      A factory component that creates Predicate instances from configuration. Each factory
      has a name (used in YAML configuration) and associated argument types.
    category: Configuration
    tags:
      - Factory
      - Routing

  - term: Gateway Filter Factory
    definition: >-
      A factory component that creates GatewayFilter instances from configuration. Enables
      request/response transformation, circuit breaking, rate limiting, and header manipulation.
    category: Configuration
    tags:
      - Factory
      - Filter

  - term: Circuit Breaker
    definition: >-
      A resilience pattern implemented in Spring Cloud Gateway via the CircuitBreaker filter,
      typically backed by Resilience4J. Trips when upstream failures exceed a threshold,
      routing to a fallback URI.
    category: Resilience
    tags:
      - Fault Tolerance
      - Resilience4J

  - term: Rate Limiter
    definition: >-
      The RequestRateLimiter filter factory that limits requests per second using a Redis-backed
      token bucket algorithm. Configurable per key (user, IP, API key).
    category: Traffic Management
    tags:
      - Throttling
      - Redis

  - term: Load Balancing
    definition: >-
      Routing requests to multiple instances of a service using the lb:// URI scheme combined
      with Spring Cloud LoadBalancer. Supports round-robin and random strategies.
    category: Traffic Management
    tags:
      - Resilience
      - Service Discovery

  - term: WebFlux
    definition: >-
      The reactive web framework on which Spring Cloud Gateway is built. Uses Project Reactor
      and Netty for non-blocking, event-driven request handling.
    category: Foundation
    tags:
      - Reactive
      - Non-Blocking
      - Netty

  - term: Actuator API
    definition: >-
      The management HTTP endpoints exposed at /actuator/gateway that allow runtime inspection
      and manipulation of routes, filters, and predicates without application restart.
    category: Management
    tags:
      - Runtime Management
      - Operations

  - term: Route Refresh
    definition: >-
      The process of reloading route definitions from the configuration source, triggered via
      the /actuator/gateway/refresh endpoint or Spring Cloud Bus events.
    category: Operations
    tags:
      - Dynamic Configuration
      - Refresh