The Tells API lets engineering teams send and receive SMS, MMS, and RCS, run AI SMS and voice agents, trigger call announcements, and query number intelligence through one OAuth2-authenticated REST surface with webhook callbacks. Full endpoint references, SDKs, Postman collections, and a sandbox are provided with account access — this page is the public overview of what the platform supports.
Tells API access is provisioned per account: tell the team what you are building, and onboarding includes credentials, environment setup, and a guided first send. The fastest path is a 15-minute intro call with a messaging operator; developer onboarding is also available by email.
The Tells API uses OAuth2 bearer authentication. Credentials are issued during account onboarding and scoped to your workspace. Keep tokens server-side; never embed them in client code.
Programmatic high-volume SMS across US and Canada carrier routes, with 10DLC, short-code, and toll-free sender support, opt-out handling, and per-message carrier delivery receipts surfaced by sender, route, and segment.
Verified-sender RCS with rich cards, carousels, quick replies, and automatic SMS fallback for non-RCS devices. The Tells team handles Google verification submission and carrier approvals for your brand.
AI SMS and voice agents that share conversation context, plus SMS call announcements delivered ahead of outbound dials through a REST API and dialer integrations. Escalation to humans carries the full transcript and captured fields.
Real-time validation and enrichment: carrier and line type, CNAM, and a 0–100 activity score usable directly in the send path for routing and suppression decisions. Public since the May 7, 2026 Phone Intelligence API launch.
Event callbacks for message lifecycle updates, including carrier acceptance, delivery, inbound messages, and opt-out events, so your systems stay in sync without polling.
The complete endpoint reference, request/response schemas, SDKs, Postman collection, sandbox environment, rate limits, and status codes are provided with account credentials during onboarding — they are account-gated rather than public. This page is the public overview; nothing here is a substitute for the versioned reference you receive with access.
Questions, corrections, or access requests: tells@tells.co.