Limits and plans
Every feature works the same for everyone: the SMTP sandbox, the public address, the SPF, DKIM and DMARC results, the API, waiting for an email, webhooks. A plan changes only limits and persistence.
| Free (no account) | Permanent inbox (paid) | |
|---|---|---|
| Address and credentials | End 60 minutes after you last used them | Permanent |
| Largest message | 2 MB | 15 MB |
| Messages | 30 per hour | 5,000 per month |
| Storage | 10 MB, up to 200 messages, kept in memory only | 1 GB on disk (encrypted); the oldest mail is dropped to make room |
| How long mail is kept | Until the session ends or the server restarts | 30 days |
| Webhook | Ends with the session | Kept, with its delivery history |
See the Account page for the current price and to subscribe. Billing is monthly and you can cancel at any time; the paid limits continue to the end of the period already paid.
Free sessions
- They are anonymous: no account, no email address, no card. A session is an id and a secret, held by your browser or your test code.
- They are kept in memory only, never written to disk, and end 60 minutes after the last use. Every API call and every open browser tab counts as use. A server restart also ends them. Do not rely on one for anything you cannot recreate.
- Creating a session is protected by a bot check, so it is done in a browser. After that, the id and secret work from any program (Test email in CI).
A permanent inbox
Sign in with GitHub or Google on the Account page and subscribe. You get:
- An address that never changes (
<id>@mail.emailblackhole.io, and<id>+anything@...for per-run recipients) and credentials that never expire. - API keys: revocable bearer tokens, each tied to your inbox only. They also work as the SMTP password. Use one per pipeline, so you can revoke it without touching the others.
- Mail kept for 30 days, then deleted automatically. If a payment fails, paid limits continue for a short grace period, then the free limits apply and your mail is kept until the 30 days pass. If you subscribe again within that time, everything is back.
- Deleting your account cancels the subscription and erases the inbox, mail, keys and webhook.
Rate limits you may meet
| Where | Limit |
|---|---|
| Creating sessions | 20 per hour per client address |
| Waiting and live streams | 10 at once per session (open browser tabs count) |
| Recipients per message | 50 |
| Webhook registrations | 20 per session per hour |
When a limit is hit, SMTP answers with a temporary 4xx code for connection and rate limits (your sender retries), or a permanent 5xx when a message is simply too big. The API answers 429 and, when the server is restarting or busy, 503 with a Retry-After header.