Arythmatic Flow Docs
Docs / Building

API builder

Define a real hosted endpoint — schema, logic and auth — when the thing you need does not justify a service.

For endpoints that never justify a repository, a pipeline and a host: a webhook receiver, an internal lookup, a prototype that has to be genuinely callable.

Defining an endpoint: schema on the left, processing logic in the middle.
Defining an endpoint: schema on the left, processing logic in the middle.

Building one#

  1. Open Build → API Builder and create an endpoint.Choose a method and a path.
  2. Define the request schema.Fields and types. Requests that do not match are rejected before your logic runs.
  3. Write the processing logic.What it does with the input and what it returns.
  4. Add auth if it needs it.An API key or bearer token, checked before anything else.
  5. Call it.It is live on its URL. There is nothing to deploy.

What it is good for#

CaseWhy here rather than a service
Webhook receiverAccept, validate, record — no infrastructure to keep running
PrototypeAnswers "can I actually call it?" in a way a mock cannot
Internal lookupStops the same helper being copied into three codebases
API over a tableThe data keeps a human owner; the consumer gets an endpoint

Where the line is#

If you can describe what it does in one sentence, and that sentence is unlikely to grow, a hosted endpoint is the right size. If describing it takes a paragraph, it wants a repository.

Publishing documentation#

  1. Open the collection's Docs tab and publish.Requests, schemas and examples become a page on a public URL.
  2. Share the link.Another team can discover the endpoint and call it correctly without asking you.

Frequently asked questions#

Can I build an API without writing a backend?

Yes, for small endpoints. Define the method, path, request schema and processing logic, and it is hosted immediately with no deployment step.

When should I use a real service instead?

When it has substantial state, needs its own database, or will grow steadily in complexity. The builder suits endpoints whose behaviour fits in a sentence.