---
title: Introduction | Rails
description: Guides and API reference for Rails banking APIs—users, accounts, ledger, and official SDKs.
---

Getting started › Introduction

Learn what Rails offers, how to run your first request, and where to read HTTP details and SDK examples.

## At a glance for planning

- **What it is:** banking infrastructure you call over HTTP—users, balances, and a ledger behind one API.
- **Who uses it:** product and engineering teams building fintech, internal tools, or regulated money flows.
- **Why it exists:** keep identity, transfers, and audit history explicit instead of hiding them inside one application database.
- **Open source:** you can read and run the core services locally; the published SDKs follow the same API this site documents.

**Rails** is banking infrastructure: identity, accounts, and a double-entry ledger behind one gateway. Use it when you need code-driven control of users, balances, and money movement that must complete fully or not at all—without packing all of that into a single database or deployable.

## What you will learn

menu\_book

### How the platform is shaped

Users, accounts, and ledger run as separate services so a failure in one area is less likely to take down everything, and each service has a clear contract. Guides explain how the pieces connect and how to run samples or the open-source stack on your laptop.

terminal

### How to integrate from code

Official SDKs are built from the same API description as this site, so method names and routes stay aligned with what you read here. Use guides for concepts, then open the API Reference tab for paths, request bodies, and copy-ready examples.

For exact URLs, request and response shapes, and per-language snippets, use the **API Reference** tab. It stays aligned with the published SDKs you install from package managers.

## Quickstart

Choose how much you want to run locally: sample apps only, or the full open-source services.

[play\_arrow](/guides/quick-start/index.md)

[**Quick start**](/guides/quick-start/index.md)

[First requests, environment variables, ports, and when to use SDK samples versus the full rails-core stack.](/guides/quick-start/index.md)

[shield\_person](/guides/authentication/index.md)

[**Authentication**](/guides/authentication/index.md)

[Where to put API keys, which base URL to call, and what to expect for HTTPS in development.](/guides/authentication/index.md)

[account\_tree](/guides/architecture/index.md)

[**Architecture**](/guides/architecture/index.md)

[How requests reach the gateway, which service owns what, and how HTTP routes map to backends.](/guides/architecture/index.md)

[terminal](/guides/sdk-overview/index.md)

[**SDK overview**](/guides/sdk-overview/index.md)

[Supported languages, install commands, and how each client lines up with the HTTP API.](/guides/sdk-overview/index.md)

## Explore

Browse the live HTTP catalog and per-language snippets. For runnable demo servers and repo layout, follow **Quick start**; for install commands per language, see **SDK overview**.

[menu\_book](/api/index.md)

[**API Reference**](/api/index.md)

[Every route, with request and response examples and snippets in each supported language.](/api/index.md)

**Runnable samples:** step-by-step setup is in [Quick start](/guides/quick-start/index.md) (including the

[`rails-sdk-samples`](https://github.com/railsinfra/rails-sdk-samples)

folders). [SDK overview](/guides/sdk-overview/index.md) lists each client package and how it maps to the HTTP API.