DEVELOPER DOCUMENTATION

Build with
Project Blue.

Messaging that feels personal. Calling that fits your app.
Everything you need to connect with your customers.

Send your first message Explore the API

What are you building?

Choose a place to start

Send your first message

Go from an API key to a delivered iMessage or SMS, step by step.

Start the quickstart

Receive events

Bring incoming messages and call events into your application.

Set up webhooks

Voice & calling

Make regular phone calls with the Voice SDK, or use the FaceTime Audio API.

Explore voice & calling

Connect an AI agent

Give Claude, Codex, or Cursor access through the Project Blue MCP server.

Connect your tools

A SMALL REQUEST. A REAL CONVERSATION.

Your first message,
in a few lines.

Send to a phone number with a single API call. Project Blue uses iMessage when available and falls back to SMS automatically.

Get your API key

BASE URLhttps://api.tryprojectblue.com

Request

curl -X POST https://api.tryprojectblue.com/send-api-message \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "message": "Hey! Just following up on our conversation.",
    "phone": "+15551234567"
  }'

Testing on a trial?Verify your number and get started Need a hand?Find errors, limits, and troubleshooting