Limits & Quotas
Overview of API rate limits, request payload limits, and daily Gmail quotas.
The following limits apply to all accounts to ensure platform stability and protect fair usage.
API Rate Limits
| Endpoint | Limit | Window | Keyed By |
|---|---|---|---|
POST /api/send | 300 req | per minute | API key |
When a rate limit is hit, the API returns 429 Too Many Requests with a Retry-After header indicating how many seconds to wait.
Request Payload Limits
| Field | Limit | Notes |
|---|---|---|
subject | 998 chars | RFC 2822 maximum |
html | 5 MB | UTF-8 encoded |
text | 2 MB | UTF-8 encoded |
to / cc / bcc | 50 each | String or array of strings |
attachments | 20 files · 10 MB/file | Base64-encoded. 25 MB total cap enforced by Gmail. |
Account & Daily Limits
| Resource | Limit | Notes |
|---|---|---|
| Connected Gmail Accounts | 50 | Per Devner user account |
| Active API Keys | 100 | Per Devner user account |
| Monthly Sending Limit | Unlimited | Resets monthly based on your account sign-up date |
| Email Log Retention | 90 days | Logs are automatically deleted after this period |
Personal Gmail (@gmail.com) | 500 emails / day | Resets daily at UTC midnight. Google hard cap is 500. |
| Google Workspace Account | 2,000 emails / day | Resets daily at UTC midnight. Google hard cap is 2,000. |
Daily sending quotas are set and enforced directly by Google's Gmail API. Devner monitors your send volume and resets your limit tracking daily at UTC midnight.