Sendblue is a business messaging service for iMessage, Apple's messaging protocol, with SMS and RCS as other channels. Messages arrive as real iMessages (blue bubbles), with read receipts, typing indicators and full-quality photos, videos and voice memos. The site's footer names Round One Inc., in New York.
A developer gets an API key, installs the SDK for Node.js or Python (or calls the REST API from any language), and sends a POST request with the recipient's phone number and the text. Incoming replies reach the developer's server through webhooks, so a program or an AI agent can hold the conversation. Sendblue detects whether the recipient has iMessage and falls back to SMS when needed, and it needs no Apple hardware or Mac server on the customer's side. Sales teams can use it from their CRM, with a shared inbox, group chats, workflows and FaceTime Audio calls. The site says no A2P registration (the approval process for business text messaging in the USA) is needed.
Sendblue is a hosted service priced per phone line per month, without per-message fees; a free sandbox exists for testing.