Best Email APIs with a Free Trial

Authkey is a multi-channel CPaaS platform providing SMS API, WhatsApp Business API, Voice API, Email API, and Google RCS. It helps businesses send notifications, promotional messages, transactional messages, OTPs, 2FA, and more. Designed for responsiveness and ease of use, Authkey allows you to start without adding any credit cards. Authkey offers a free sandbox account for building, testing, and deploying. It supports easy-to-integrate APIs for all channels and over 1,000 automation options via Zapier, Pabbly, Integrately, and other partners. You can easily push bulk campaigns through all channels. WhatsApp Chatbot for intelligent customer query responses. Join over 200 active businesses working with us and grow together.

Unipile is a unified API designed to integrate multiple communication channels, messaging, email, calendar, and more, into your software application. It provides over 500 endpoints that enable developers to connect platforms such as LinkedIn, WhatsApp, Instagram, Gmail, Outlook, and IMAP into a single unified inbox. With Unipile, you can send and retrieve messages across channels, manage calendars (Google/Outlook), sync conversations in real time, and maintain full historical context across channels. The API supports functions such as starting chats, retrieving message threads, scheduling events, and connecting profile data, all through the same interface. Use-cases include ATS/CRM software publishers, outreach tools, no-code builders, and AI agent platforms, anywhere multi-channel communication needs to be embedded into an application. Unipile also emphasizes rapid integration, developer-friendly documentation, and live support.

Infobip is a global leader in omnichannel engagement powering a broad range of messaging channels, tools and solutions for advanced customer engagement, authentication and security. With over 700 direct carrier connections and 60+ offices on 6 continents, Infobip is the #1 choice of some of the world's biggest companies to scale their customer communications. We help our clients and partners overcome the complexity of consumer communications, grow their business and enhance customer experience, all in a fast, secure and reliable way. With Infobip, you can achieve deeper customer engagement across the widest selection of local and global channels, including: SMS MMS RCS Live Chat WhatsApp Business Apple Messages for Business Facebook Messenger Instagram Business Telegram Viber Voice / VOIP Video Email