Introduction

Postbox is agent-native data collection. You create a form, you get an endpoint. POST data from anywhere - an HTML form, a cURL command, a script, an AI agent. Postbox handles everything after submit. Your data arrives validated and clean, and your agents can manage it all.

What Postbox does

1. Collects - Accepts structured data via HTTP POST at your unique endpoint
2. Validates - Enforces your schema: required fields, types, and formats
3. Spam protection - Built-in heuristic checks or AI-powered detection to filter spam before it reaches you
4. Translates - Auto-detects language and translates submissions
5. Replies - AI-generated smart replies sent to submitters automatically

Who sends the data?

Postbox doesn’t care. Your endpoint accepts data from:

• HTML forms / JavaScript - Submit via fetch from any frontend or framework
• cURL / scripts - Bash scripts, cron jobs, CI pipelines
• AI agents - Via direct HTTP or the MCP server

Key concepts

• Form - A named data collection point with a schema, validation rules, and processing settings
• Endpoint - The unique URL where data is POSTed (looks like https://usepostbox.com/api/.../f/{slug})
• Submission - A single data entry received at an endpoint
• Webhook - Outbound HTTP delivery of submission data to your server, signed and retried
• Knowledge Base - Context documents that power AI smart replies for a form
• API Key - Your authentication token for the management API
• Submission Token - Authentication token for submitting to private forms (returned once at creation)

Next steps

Ready to collect your first submission? Head to the Quickstart.