Reloop

Developers who need to send transactional or marketing email today face a setup burden: learning tutorials, creating API keys, configuring domains, figuring out DNS, and spending hours connecting email infrastructure before sending a first message. Closed email providers like AWS SES, Resend, SendGrid, or Postmark offer limited transparency into queues, delivery pipelines, and DNS checks, creating vendor lock-in. Teams also face a 'contact tax' from providers that charge storage fees on stored or inactive leads. AI agents and automated workflows typically lack a simple way to receive, parse, and reply to email without custom plumbing.

Reloop provides a REST API, SMTP relay, and first-party SDKs for Node.js, TypeScript, Python, Go, Rust, PHP, and Ruby, letting developers send transactional and marketing email with minimal setup, including via natural language commands to an AI agent ('Set up email for my app using Reloop'). It includes an MCP server so AI agents like Claude, Cursor, or Codex can send and manage email directly, plus a CLI for sending and testing email from the terminal. Deliverability features include SPF/DKIM/DMARC authentication, IP reputation and warmup management, dedicated IPs, blocklist tracking, phishing and spoofing protection, and smart bounce handling. It also offers inbound email webhooks and dedicated agent inboxes with spam scoring and threading, AI-generated email templates with a visual editor, campaign tools (broadcasts, segments, scheduling), and unlimited contact storage without penalty for inactive leads. Reloop is open source under Apache 2.0 and can be self-hosted for free or used as a hosted Cloud service with a free tier of 6,000 emails per month.