Novu

Novu gives you one API for every notification channel: email, SMS, push, in-app, and chat, so you stop duct-taping Twilio, SendGrid, Firebase, and Slack together yourself. You define a notification workflow once and it routes to the right channel based on each subscriber's preferences.

The self-hosted open-source version is free and includes the core workflow engine, template management, subscriber preferences, and all the channel integrations. It runs via Docker Compose with MongoDB, Redis, and the Novu workers, an hour or two to set up and a moderate ongoing ops burden since you're running a multi-service stack with queues and a database.

Cloud is metered by workflow runs now, not events. Solo developers: the free cloud tier (10,000 runs/month) covers most side projects. Small teams: free tier still works at low volume, or Pro from $30/mo. Growing teams: self-host to dodge per-run costs, or pay $250/mo for the Team tier to skip the ops. The newer versions also lean into an AI agent runtime, so Novu is drifting from pure notifications toward agent messaging.

The catch: Novu has rearchitected more than once. It's now on a v3, code-first line that's cleaner but has broken backward compatibility along the way. If you built on older patterns, expect migration work, and keep an eye on how far the AI-agent pivot pulls the core product.