Key Takeaways
- A feed API serves a stream of items - activity, posts or notifications - newest or most relevant first.
- The hard part is fan-out: delivering one new item to the feeds of many followers.
- Feeds are read with pagination (cursors) and kept live with WebSockets or webhooks.
- RSS and Atom are the classic public feed formats; JSON APIs are the modern equivalent.
What Is a Feed API?
A feed API lets an application add items to, and read items from, a feed: an ordered stream such as a social timeline, an activity log ("Ana commented on your ticket"), a news feed or a notification inbox. Instead of designing storage, ordering and delivery yourself, you call endpoints like add activity and get feed.
How a Feed API Works
- Write: an item (actor, verb, object, time) is added to a source feed.
- Fan-out: the item is copied or referenced into every feed that follows the source - on write (fast reads) or on read (cheap writes for accounts with huge audiences).
- Read: the client fetches a page of items with a cursor, then the next page as the user scrolls.
- Real time: new items are pushed over a WebSocket or announced with a webhook.
- Ranking: some feeds are chronological, others re-ordered by relevance.
Common Types of Feeds
| Feed | Example |
|---|---|
| Activity feed | Changes on a project, ticket or CRM record |
| Social timeline | Posts from accounts a user follows |
| Notification feed | Mentions, replies and alerts with read and unread state |
| Syndication feed | RSS or Atom for blogs and podcasts |
Chatbots often post into feeds too - for example a bot that sends new leads into a Slack channel.
Frequently Asked Questions
What is a feed API used for?
It is used to build streams of updates inside an app: social timelines, activity logs on records, notification centres and news feeds. The API handles storing items, delivering them to followers, ordering and pagination, so developers do not have to engineer fan-out and ranking themselves.
What is the difference between a feed API and RSS?
RSS and Atom are public XML formats that publish a site's latest items for readers to poll. A feed API is usually a private JSON interface inside an application that also handles following, fan-out, read state and real-time updates. RSS is one simple kind of feed; feed APIs are broader.
What is fan-out in a feed?
Fan-out is delivering one new item to everyone who follows its source. Fan-out on write copies it into each follower's feed immediately, making reads fast; fan-out on read assembles the feed when it is opened, which suits accounts with very many followers. Large systems often mix both.
How do feed APIs stay real time?
Clients fetch a page of items on load, then receive new ones through a persistent connection such as a WebSocket or server-sent events. Servers that integrate with other systems are notified through webhooks instead of polling the feed repeatedly.
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