> ## Documentation Index
> Fetch the complete documentation index at: https://docs.qbraid.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Overview

> Learn to work with qBraid APIs

Our API employs a [RESTful](https://en.wikipedia.org/wiki/REST) architecture, featuring intuitive,
resource-oriented URLs and leveraging inherent HTTP capabilities such as response codes, authentication,
and verbs.

We support cross-site requests from any domain and return responses in JSON format.

## Quantum Job Flow

The diagram below gives a high-level view of how a quantum job moves through an application that integrates with the qBraid API: from a high-level quantum program, to an intermediate representation (IR), to the qBraid API server, then to execution on a quantum backend, with results relayed back to the user.

<img src="https://mintcdn.com/qbraidco/RuRPz_FGuIRFuVFj/v2/api-reference/_static/qbraid-runtime-api.svg?fit=max&auto=format&n=RuRPz_FGuIRFuVFj&q=85&s=1163543194f49940f5c0fa586a88ffff" alt="qBraid Runtime API Server" width="1005" height="719" data-path="v2/api-reference/_static/qbraid-runtime-api.svg" />

For a client-side view of how the qBraid-SDK integrates with the qBraid API see the [Runtime overview](/v2/sdk/user-guide/runtime/components#runtime-overview) in the SDK docs.

## Rate limiting

API requests are rate-limited per IP (unauthenticated) or per user (authenticated) within a rolling 15-minute window.

| Tier                 | Window | Max requests |
| -------------------- | ------ | ------------ |
| Unauthenticated (IP) | 15 min | 100          |
| Authenticated user   | 15 min | 1,000        |

Exceeding the limit returns an HTTP 429 (Too Many Requests) response. Authenticate with a valid API key to use the higher authenticated limit.

<Tip>
  Higher rate limits for your [organization](/v2/organizations/overview) are
  available upon request.
</Tip>