API reference · v1
API rate limits
Limits are on concurrent in-flight requests per key, not requests per minute, because SMTP checks vary in duration. Every response includes X-RateLimit-Limit, X-RateLimit-Remaining, and, on 429, Retry-After.
| Plan | Concurrent requests | Bulk rows per job |
|---|---|---|
| Free | 2 | 1,000 |
| Starter | 5 | 100,000 |
| Growth | 20 | 1,000,000 |
| Scale | 100 | Unlimited |