Send email

Twilio SendGrid

Email delivery service with an HTTP API and SMTP relay that sends transactional and marketing email and reports delivery events.

Rate limits

Web API v3: Fixed number of requests per endpoint per refresh period; 429 when exceeded; limits are returned in X-RateLimit-* headers9
Free trial sending: 100 emails a day for 60 days26

Other limits

Email size: Under 30 MB including attachments5
Recipients per request: 1,000 across to, cc and bcc5
Scheduling window: 72 hours10
API keys per account: 1008
Custom args size: Under 10,000 bytes5

Read from Twilio’s own pages on 2026-11-04. Every number links to the page a value came from. For agents, the same facts as markdown: /tools/send-email/sendgrid.md