Ably
Real-time messaging infrastructure platform for pub/sub messaging, presence, and connection state synchronization, with SDKs for most languages.
Use Cases
Free Tier
6M messages/month, 200 concurrent connections, 200 channels, 500 messages/second, 1-day message storage, 64KiB max message size. Community support.
How to Maximize the Free Tier
The free tier is one of the most generous in real-time infra: 6M messages/month with 500 msg/s is plenty for a live dashboard or collaborative feature. The real constraints are 200 concurrent connections and 1-day message storage — a public room can hit the connection cap during a spike, and you can't replay old messages, so persist anything you need via webhooks to Neon or Supabase. Presence is included (200 members/channel), which other vendors charge for. For production, issue short-lived tokens from a Cloudflare Worker instead of shipping your API key to clients. The 64KiB message size limit means keep payloads small or split large updates.
Getting Started
Sign up at ably.com → create a new app in the dashboard and copy the API key → install the SDK (npm install ably) → initialize the client with your API key → subscribe to a channel: channel.subscribe('update', (msg) => console.log(msg.data)) → publish from another client: channel.publish('update', 'Hello') → for production, add a token request endpoint on your backend or a Cloudflare Worker.
Pros
- Message volume: 6M messages/month with 500 msg/s is a genuine free tier, not a trial — enough for real apps
- Presence included: Built-in presence and connection state tracking (200 members/channel) is often a paid feature elsewhere
- Reliability: Free tier runs on the same production infrastructure with a strong uptime reputation
Cons
- Short retention: Only 1-day message storage means you cannot use Ably as a data store — build your own history layer
- Connection cap: 200 concurrent connections is a hard limit; a popular public channel can hit it quickly
- Community support: No guaranteed response times on the free tier — support is best-effort via community channels