The best Postbox alternative
An AI-agent-native form backend (usepostbox.com) with its own MCP server, schema versioning, and a self-documenting API — the most direct AI-tool-channel competitor FormLoom has found. Here’s how FormLoom compares — honestly, including where Postbox wins — and how to switch.
FormLoom vs Postbox
| Feature | FormLoom | Postbox |
|---|---|---|
| Free submissions / mo | 250 | 5,000 |
| Free storage | Forever — no expiry | 5,000 lifetime submissions total (not monthly) — then upgrade required |
| Free file uploads | ||
| Free webhook | ||
| MCP server | ||
| llms.txt | ||
| Free dashboard | Full | Full |
| Spam protection | AI spam score + honeypot + captcha, on by default | Two-layer: honeypot + rate limiting + bot signatures, plus an AI intent classifier |
| Paid entry (~10k/mo) | $18/mo | $19/mo |
Why switch
- No file uploads at all, even on Pro — the Postbox FAQ says it's still 'on the roadmap.' FormLoom supports uploads (10MB free, 25MB Pro).
- Postbox's MCP is schema-introspection (an agent discovers your fields via API calls); FormLoom's get_snippet hands back ready-to-paste, framework-idiomatic code with a live provisioned key already embedded — one call, no follow-up requests.
- Postbox's free tier is a 5,000-submission lifetime cap, not a monthly allowance — a long-lived low-volume project eventually hits a wall. FormLoom's 250/mo resets every month, forever.
Where Postbox wins
Postbox genuinely ships an MCP server and an llms-full.txt — it's the first form backend we've found besides FormLoom with both. Its schema versioning (every field change mints a new endpoint URL; old ones keep validating against their original schema forever) is a real, clever feature FormLoom doesn't have. Pro is a flat $19/mo for unlimited forms and submissions, which beats FormLoom's metered overage at high volume.
Migrating from Postbox
- 1Create a FormLoom form to get your access key (the form id).
- 2Replace your Postbox endpoint URL (or SDK key) with FormLoom's.
- 3Keep your existing form markup — only the action/key changes.
- 4Redeploy and submit a test; new submissions land in FormLoom.
FAQ
Yes — FormLoom matches the core form-backend functionality and adds 250 free submissions/mo, permanent storage, AI spam scoring, and an MCP server for AI coding tools. No file uploads at all, even on Pro — the Postbox FAQ says it's still 'on the roadmap.' FormLoom supports uploads (10MB free, 25MB Pro).