# API Reference

> The Submission API behind every Formclick form: endpoints, payloads, file uploads, webhooks and errors.

Source: https://docs.formclick.io/api-reference

## Overview

- [API overview](https://docs.formclick.io/api-reference/overview.md): Everything a Formclick form does goes through a small, public HTTP API. Use it directly from any language.
- [Authentication](https://docs.formclick.io/api-reference/authentication.md): Submissions are authenticated with your form’s public access key.

## Endpoints

- [Submit endpoint](https://docs.formclick.io/api-reference/api-reference.md): The submission endpoint: URL, methods, content types, fields and responses.
- [REST API (forms & submissions)](https://docs.formclick.io/api-reference/rest-api.md): Read and manage forms, submissions and webhooks with an OAuth access token. Powers the Formclick app on Make.
- [File upload API](https://docs.formclick.io/api-reference/file-upload-api.md): Upload files directly to storage with one-time URLs, then reference them in a submission.
- [Webhook events](https://docs.formclick.io/api-reference/webhook-events.md): The JSON Formclick sends to your webhook for each new submission.

## Reference

- [Errors](https://docs.formclick.io/api-reference/errors.md): Every error the endpoint can return, what causes it and how to fix it.
- [Rate limits & quotas](https://docs.formclick.io/api-reference/rate-limits.md): Per-IP limits, duplicate detection, size limits and monthly plan quotas.