Custom APIs

Custom APIs are HTTP routes you register on Archie’s gateway that reverse-proxy to internal services. Each route maps a public-facing URL path to a target URL and brings the target under the same auth, CORS, rate-limiting, and resilience policies as the rest of your backend. Use a Custom API when:

You have an existing internal service you want to expose under your project’s domain.
You want CORS, rate limiting, or a circuit breaker in front of a third-party endpoint.
You need request/response transformation that doesn’t belong in your service code.

For CRUD against the Data Model, you don’t need a Custom API — the auto-generated GraphQL and REST APIs already cover that. To open it, navigate to App Services → Custom APIs in the Backend Console.

Per-environment scoping

Routes are scoped per environment. Each environment has its own routes — production routes can point at production services while dev routes point at staging instances of the same service. When branching an environment with the Gateway routes copy option, every route is duplicated into the new environment. Each copy receives a new ID and can be edited independently.

Registering a route

The configuration is split across four tabs: General, Security, Request & Response, and Resilience.

General — routing logic

The General tab defines what the route catches and where it goes.

Field	Purpose
Path	Public-facing URI path clients call (e.g., `/api/v1/users`).
Target URL	Internal destination URL where the gateway forwards the request.
Methods	HTTP verbs the route responds to: `GET`, `POST`, `PUT`, `PATCH`, `DELETE`.
Enabled	Toggle to activate or deactivate the route without deleting it.

Security — CORS and rate limiting

The Security tab controls cross-origin access and rate limits per route.

CORS

Setting	What it does
Allow All Origins	Accept requests from any domain. Disable to use the allowlist.
Allowed Origins	Whitelist of specific domains permitted to call the route.
Allowed Methods & Headers	HTTP verbs and custom headers the gateway will accept.
Allow Credentials	Whether browsers should include cookies or auth headers.
Preflight Cache Duration	How long browsers cache the CORS preflight response.
Expose Headers	Response headers safe to expose to the client.

Rate limiting

Setting	What it does
Average	Baseline requests allowed per time unit.
Burst Allowance	Extra requests allowed in short spikes above the average.
Time Window	Counting period — typically per second or per minute.
Rate Limit by	How to identify unique callers — typically by IP address.

When the limit is exceeded, the gateway returns 429 Too Many Requests with a Retry-After header.

For project-wide CORS and rate-limit defaults, see Backend → Settings → Network.

Request & Response — transformations

The Request & Response tab controls how data is shaped on the way through the gateway.

Custom headers

Add or override headers per route:

Custom request headers — sent to your backend on top of what the client sent.
Custom response headers — added to the response on the way back.

Each header is a name and a value. Useful for injecting service-to-service auth tokens or stamping responses with a Cache-Control policy.

Path rewriting

Modify the request path before it reaches your backend:

Operation	Example
Strip prefix	`/v1/users/123` → `/users/123` (strip `/v1`).
Add prefix	`/users/123` → `/api/users/123` (add `/api`).
Regex pattern & replacement	`^/old/(.*)` → `/new/$1` for arbitrary remapping.

Query parameter forwarding

Choose which query string parameters reach the backend:

Mode	Behavior
Forward all	Pass the entire query string unchanged.
Allow list	Forward only the named parameters.
Deny list	Forward all parameters except those explicitly blocked.

Body size limits

Setting	Purpose
Request body size limit	Maximum size of incoming request bodies.
Response body size limit	Maximum size of outgoing response bodies.

Exceeding either limit returns 413 Payload Too Large.

Resilience — timeouts, circuit breakers, caching

The Resilience tab keeps your route healthy when the backend doesn’t cooperate.

Custom timeout

How long the gateway waits for a response before giving up. Set between 1 and 300 seconds. Without a timeout, a slow backend can pin gateway capacity indefinitely.

Circuit breaker

Automatically stop forwarding requests to a failing backend so failures don’t cascade. Apply a preset or write a custom expression:

Preset	Trips when
50% errors	Error ratio crosses 0.5 over the check window.
30% errors	Error ratio crosses 0.3.
High latency	p99 response time crosses the threshold.
500+ errors	Sustained 5xx responses.

Setting	Purpose
Expression	Custom trip condition (e.g., `NetworkErrorRatio() > 0.5`).
Check (s)	How often the breaker checks while open.
Fallback (s)	Wait before attempting a partial close.
Recovery (s)	Recovery phase duration before fully closing.

Response caching

Setting	Purpose
Cache TTL (seconds)	Time-to-live for `GET` responses. Subsequent identical requests within the TTL are served from gateway cache.

Caching applies only to safe (GET) requests. Mutations are never cached.

Programmatic management

Routes can also be created via GraphQL — useful for codifying gateway configuration alongside your data model.

mutation RegisterRoute($input: RegisterRouteInput!) {
  registerRoute(input: $input) {
    id
    path
    targetUrl
    methods
    enabled
    environment
  }
}

When you delete an environment, all routes attached to it are cleaned up automatically. To delete environment routes manually:

mutation DeleteRoutesByEnvironment($input: DeleteRoutesByEnvironmentInput!) {
  deleteRoutesByEnvironment(input: $input) {
    deletedCount
  }
}

Permissions

Custom API routes inherit the same auth and authorization model as the rest of your backend. Authenticated requests carry their roles to the route, where you can apply per-route policy. For full coverage, see Role-Based Access.

FAQ

When should I use a Custom API instead of a custom function?

Use a Custom API when you have an existing service to expose — the gateway adds CORS, rate limiting, and resilience without code. Use a custom function when the logic itself runs inside Archie. The two compose: a Custom API can route to a custom function the same way it routes to any backend.

Are routes copied between environments?

Optionally — tick Gateway routes in the branching modal. Each copy gets a new ID. After branching, edits in either environment are independent.

What's the difference between per-route CORS and the Network settings?

Settings → Network sets the default CORS for the auto-generated GraphQL and REST APIs. Per-route CORS overrides that for a specific Custom API path.

Can I cache POST requests?

No — caching only applies to GET. Caching mutations would silently return stale state to clients that expected fresh writes.

What happens when the circuit breaker opens?

The gateway short-circuits incoming requests with a 503 Service Unavailable response without forwarding to the backend. After the recovery period, it lets a small number of probe requests through to test whether the backend has recovered before fully closing the circuit.

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