Customer.io App API

Business · Operational · 30d uptime 100%

API for Customer.io campaigns, newsletters, transactional messages, and workspace resources. Official documentation: https://customer.io/docs/api/app/

Trust signals

Pricing

FREEMIUM

Auth

API_KEY

CORS

Yes

Rate limit

Unknown

Health

130ms

Trust score

97 (A)

Last checked Oct 16, 2026 · uptime 24h 100% / 7d 100% / 30d 100%

Excellent production-readiness signals.

Links

Integration checklist

Auth is API_KEY
CORS enabled — callable directly from browsers.
Rate limit: not documented

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