Build billing infrastructure with Railzway

Guides and API references for deterministic metering, pricing, subscriptions, invoicing, and payments.

Railzway Fare is the open monetization engine for modern SaaS products. Turn product usage into explainable charges and invoice-ready financial records while keeping pricing logic versioned, auditable, and under your control.

Contract-first by design

Every public API starts from versioned Protocol Buffer contracts and is available through gRPC and REST/JSON transcoding.

Start building

Quickstart

Send your first request and complete a billing workflow.

API reference

Explore every generated Fare endpoint and schema.

Core concepts

Learn how usage becomes deterministic financial output.

Authentication

Connect securely with organization-scoped API keys.

One billing flow, clear boundaries

usage event -> meter -> product -> effective rate -> contract
            -> rated charge -> credits -> invoice -> payment

Railzway keeps computation separate from collection. Finalizing an invoice records what is owed; collecting it is an explicit operation. This boundary makes every financial outcome easier to reproduce, inspect, and explain.

API essentials

Build on predictable platform conventions before integrating individual resources.

Base URLs

Choose an organization subdomain or configure a custom domain.

Idempotency

Safely retry mutating requests without duplicating financial operations.

Errors

Handle the shared error envelope and documented HTTP statuses.

API keys

Create, store, rotate, and revoke credentials safely.

Deployment is your choice

Run Fare as open-source infrastructure in your environment or use Railzway Cloud for managed operations. The API contract and billing model remain the same across deployment models.