Developer Documentation

Integrate JoltSMS into your applications and AI agent workflows. Authenticate with API keys, manage numbers and messages via REST, or use the MCP server for automated OTP verification and constrained SMS replies.

Quick start
curl -H "Authorization: Bearer jolt_sk_your_key_here" \
  https://api.joltsms.com/v1/numbers

Authentication

Create scoped API keys, authenticate requests with Bearer or X-API-Key headers, and understand rate limits and error responses.

  • API key creation and format
  • Bearer and X-API-Key authentication
  • Personal, enterprise, and selected-number scopes
  • Rate limits and pagination caps
  • Error responses (401, 403)
  • Session-only endpoints
  • View full guide

API Reference

Full endpoint reference for numbers, messages, billing, notifications, and team management. Includes request/response examples.

  • Numbers — list, provision, update
  • Messages — list, search, reply, mark read
  • Enterprise contracts and scoped keys
  • Billing — subscriptions, invoices
  • Notifications — endpoints, rules, logs
  • View full guide

MCP Server

Set up the JoltSMS MCP server for AI agent workflows. Provision numbers, poll for SMS, and extract OTP codes programmatically.

  • Hosted HTTP and local stdio setup
  • Claude Code, Cursor, and Claude Desktop setup
  • Tool reference (12 tools)
  • OTP verification workflow
  • Troubleshooting
  • View full guide

Webhooks

Receive real-time events when SMS arrives, numbers expire, or billing issues occur. HMAC-SHA256 signed for security.

  • Jolt Events v1 format
  • Event types (SMS, billing, numbers)
  • HMAC-SHA256 verification
  • Retry policy and DLQ
  • Endpoint setup in dashboard
  • View full guide

First number? Add a card first

Add a card through the Dashboard before your first rental. We require 3D Secure authentication when saving a card, which needs you to be present in the browser. After that, the API or MCP server can provision your first or any additional number using the valid default, the sole saved card, or a saved card you explicitly select.

Base URLs

REST API requests use:

https://api.joltsms.com/v1

Hosted MCP clients use:

https://mcp.joltsms.com/mcp