# Documentation

RenderFast generates images by rendering a **template** — a canvas of text, image, and shape
layers you design once in the editor — with per-request **layer overrides**. Call the
authenticated `/api/generate` endpoint (or the public, no-auth `/api/render` URL) with a
template ID and the fields you want to change, and get back a rendered PNG, JPEG, or WebP.

Everything else — uploads, the TypeScript SDK, programmatic template edits, and rate limits —
builds on that same request shape.

> **Related: API Reference**
>
> The complete OpenAPI specification — every endpoint, request/response schema, and authentication detail — is auto-generated and always current.
>
> Open API Reference

## Where to go next

- **[Quickstart](/docs/quickstart)** — clone a starter template, create an API key, and render
  your first image
- **[Generate API](/docs/generate-api)** — the authenticated `/api/generate` endpoint, layer
  override reference, strict validation, and warnings
- **[Assets](/docs/assets)** — upload your own images and fonts and reference them with `asset:<id>` and `font:<id>`
- **[TypeScript SDK](/docs/sdk)** — the typed `@renderfast/client` package
- **[Render URLs](/docs/render-url)** — the public, no-auth `/api/render` endpoint for OG images
- **[Templates API](/docs/templates-api)** — edit templates programmatically
- **[Template Guide](/docs/template-guide)** — layer naming, canvas presets, typography, and
  testing
- **[Rate Limits & Usage](/docs/rate-limits)** — plan limits and what doesn't count against them

## Need help?

Questions about the API or template creation?
Contact our support team.