# Glossary The words these pages use for the parts of a gateway, in the order you meet them. When a page uses one of these terms, it means exactly what is written here. ## Requests and models Model id : The name a client sends in the `model` field, such as `example-chat`. It is the gateway's public name for a model and is independent of what any provider calls it. Alias : Another name that resolves to the same model id. Declared with `aliases:` on the model. Model registry : The YAML file, usually `models.yaml`, that lists every model id and the routes behind it. [Configuration](configuration.md) explains how the gateway finds it. API key and provider key : An API key is what a client presents to the gateway. A provider key is what the gateway presents to a provider. They are never the same credential. ## Routes and providers Route : One way of serving a model id: an entry in the model's `route:` list that names an adapter kind, a base URL, a credential and a weight. A model id can have several routes, and that is what lets the gateway balance and fail over between them. Endpoint : The server a route sends requests to. Pages say "endpoint" when they mean the server and "route" when they mean the configuration entry. `endpoint_id` : The gateway's key for one endpoint of one model, written `:` — `glm-4.6:local-12003` for a server on local port 12003, `glm-4.6:zai-api` for a hosted API. Circuit breakers, latency profiles and weight overrides are all keyed on it. The suffix comes from the host and port or from the adapter kind, so it does not tell you who runs the server. Provider : The service behind a route: OpenRouter, DeepSeek, your own vLLM server. In configuration, a route's `provider:` is the label its traffic is reported under in logs and dashboards. Kind : A route's `kind:`, which picks the adapter that talks to the endpoint: `openai_compat`, `vllm`, `openrouter`, `anthropic` and so on. Adapter : The code that speaks one provider's API. It builds the request, holds the provider key and turns the response back into the OpenAI shape. Self-hosted servers use the generic OpenAI-compatible adapter. Upstream : Whatever the gateway calls to produce an answer — the far end of a route. ## Choosing a route Router : The per-model logic that picks a route for each request. `fixed` draws a route at random by weight and falls back to the others on failure; it is the default. `routewise` trades latency against cost. A model chooses one with `router:`. Weight : A route's relative share of traffic under the `fixed` router. A route with weight `0` stays configured but receives no traffic, not even as a fallback. Fallback : What the router does when a route fails: it tries the model's remaining routes in order until one answers. Circuit breaker : A per-endpoint switch that stops sending traffic to an endpoint after repeated failures and lets a single test request through after a cooldown. Offload route : A route set aside for the requests a model's other routes cannot start in time. See [Queue-wait offload](routing.md#queue-wait-offload). Routing file : The optional `routing.yaml`. It holds health-probe settings and a local/remote weight split; see [The routing file](configuration.md#the-routing-file) for what it does and does not change. ## Deployments Distribution : One deployment's own files — its manifest, model registry, routing file, branding and Compose settings — kept together in `distributions//` instead of in the source. `distributions/example/` is the one this repository ships. Overlay : The `distributions//` directory itself. It is called an overlay because it is mounted over the neutral image rather than built into it. Manifest : `distribution.yaml`, the file in a distribution that names it and says where its configuration files are. Dry run and active : The two modes of `DISTRIBUTION_CONFIG_MODE`. In a dry run — the default, written `dark` in the setting — the gateway reads and checks the manifest and logs what it would change, but uses nothing from it. `active` applies it. Operational store : The Postgres tables that hold accounts, API keys and everything changed from the admin console. Runtime model : A model created from the admin console instead of the model registry. It exists only in the operational store. Console : The Next.js web app: sign-up and sign-in, the user dashboard, the playground and the admin console. It also forwards API paths to the gateway; see [The public path table](public-path-table.md). Site UI module : A distribution's own React components for the public pages, compiled into its console image. See [Site UI Modules](site-ui-modules.md). Backend extension : A trusted Python module a deployment loads at startup to add an adapter, an agent-access rule or a quota source. See [Backend Extensions](backend-extensions.md).