Verified history
This means HyperObserve has not found sufficient first-party evidence for a dated before-and-after event. It does not mean Resend has never changed. Undated values are kept in the current baseline below instead of being presented as history.
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. | 5 requests per second per team | Default | ResendAug 22, 2026 |
| free sending quotaThe daily and monthly quotas are independent and the first exhausted limit applies. | 100 emails/day and 3,000/month | Free | ResendAug 22, 2026 |
| batch and free contactsBatch requests do not support attachments. | 100 emails per batch; 1,000 marketing contacts on Free | Free and API batch | ResendAug 22, 2026 |
| post-encoding message sizeThe limit applies after base64 encoding, so source binary files need headroom. | 40 MB | Single email | ResendAug 22, 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 team rate and response headers
Free sending, contacts, overage, and batch limits
Post-encoding message size and attachment restrictions