Design an activity feed where users can see recent actions from their team or project.

Design an activity feed backend

Designs an activity feed with event capture, fan-out strategy, pagination, privacy, and read performance.

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TL;DR

I would record activity events when important actions happen, such as created, commented, assigned, uploaded, or status changed. The feed API would return recent events for a user, team, or project with cursor pagination. Each event would include actor, action, target, timestamp, and display metadata. Authorization matters because a user can only see feed items for resources they are allowed to access.

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Feed modeling, write-time versus read-time fan-out, pagination, privacy filters, caching, and operational limits.

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Why this question matters
Activity feeds combine fan-out, privacy, pagination, correction, and retention. The design must keep authorization current while deciding whether feed entries are assembled at read time or projected ahead of time.
I would record activity events when important actions happen, such as created, commented, assigned, uploaded, or status changed. The feed API would return recent events for a user, team, or project with cursor pagination. Each event would include actor, action, target, timestamp, and display metadata. Authorization matters because a user can only see feed items for resources they are allowed to access.
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I would choose between building the feed at read time or materializing it at write time. Read-time filtering is simpler and works for smaller teams, but it can become expensive when every request joins many tables and permission rules. Write-time fan-out or precomputed read models can make reads fast, but it adds complexity when permissions change or events need correction. I would keep the source event immutable and allow display projections to be rebuilt.

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Details

Ignoring authorization when reading feed items.
Using offset pagination on a constantly changing feed.
No plan for permission changes after precomputing feed rows.
Storing only display text and losing structured event data.

Design an activity feed where users can see recent actions from their team or project.

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