Verified history
Resend doubled the default API rate limit to 10 requests per second
Resend's rate-limit and account-quota pages now state a default maximum of 10 requests per second per team (previously 5). No effective date is published; detection date recorded.
Queues sized for 5 requests per second can be relaxed after confirming the team's current limit headers.
Current monitored baseline
HyperObserve currently monitors 4 scoped observations for Resend. The baseline covers default API rate, free sending quota, batch and free contacts, post-encoding message size. Each value retains its plan, product, endpoint, region, account, or runtime qualifier so a future change can be compared against the correct scope.
| Constraint | Current value | Scope | Verified source |
|---|---|---|---|
| default API rateRateLimit headers expose limit, remaining, and reset state. | 10 requests per second per team | Default | ResendSep 17, 2026 |
| free sending quotaThe daily and monthly quotas are independent and the first exhausted limit applies. | 100 emails/day and 3,000/month | Free | ResendSep 17, 2026 |
| batch and free contactsBatch requests do not support attachments. | 100 emails per batch; 1,000 marketing contacts on Free | Free and API batch | ResendSep 17, 2026 |
| post-encoding message sizeThe limit applies after base64 encoding, so source binary files need headroom. | 40 MB | Single email | ResendSep 17, 2026 |
Tracked constraints and impact
API rate, daily/monthly sends, contacts, batch, and attachment limits. A change is recorded only when it alters a constraint developers can act on, such as capacity planning, request shaping, model selection, deployment configuration, storage design, retry behavior, or account budgeting.
Resend API Rate Limit
Resend API Rate Limit, verified against Resend's official documentation with scope, implementation impact, caveats, and a direct check.
Resend Free Email Sending Limits
Resend Free Email Sending Limits, verified against Resend's official documentation with scope, implementation impact, caveats, and a direct check.
Resend Batch & Contact Limits
Resend Batch & Contact Limits, verified against Resend's official documentation with scope, implementation impact, caveats, and a direct check.
Resend Email Attachment Size Limit
Resend Email Attachment Size Limit, verified against Resend's official documentation with scope, implementation impact, caveats, and a direct check.
How a change is verified
- Compare the current first-party statement with the previously stored observation, including the exact plan, model, runtime, endpoint, region, and account scope.
- Separate a true product change from documentation clarification, temporary capacity, configurable account state, or a limit that applies to a different execution path.
- Preserve the old and new values, official source, effective date when disclosed, detection date, and practical impact. If those elements cannot be supported, no historical event is published.
Official sources monitored
These first-party documents support the current Resend baseline. HyperObserve links directly to them so you can confirm the live wording before making a production decision.
Default rate limit of 10 requests per second per team and ratelimit-* headers
Free sending, contacts, overage, and batch limits
Post-encoding message size and attachment restrictions