SendGrid · api · fg-0420

SendGrid returns 200 instead of 202 and no email is delivered

Mail Send responds 200 OK, not 202 Accepted

Verified 2026-10-15 · Confirmed by 0 builders · Trust 50/100

Cause

With mail_settings.sandbox_mode.enable true, SendGrid only validates the request and returns 200, and the message is never delivered. A flag left on from tests, or a string true, causes silent non-delivery or a 400.

Fix

Drive sandbox mode from an explicit test flag, send a real boolean, and treat a 200 from Mail Send in production as an alarm.

Apply

mail_settings: { sandbox_mode: { enable: process.env.NODE_ENV === 'test' } }  // expect 202 in production

Affects: SendGrid v3 Mail Send, as of 2026-10

Sources

Have your agent know this before it fails

claude mcp add --transport http footgun https://getfootgun.com/api/mcp