Offline and sync case studies
These cases are about an app that must keep working when the network is bad or gone. You design a place on the phone that saves each change first. Then you design how the changes reach the server later, and how to fix a conflict when two people edit the same thing. The hard parts are safe retries, uploads that can resume, and merging edits. Read the chat app first. It teaches the outbox, and the other cases build on it.
Main case studies in this topic
- Design a chat appOutbox, safe retries (idempotent sends), and sync with WebSocket and push.
- Topic
- Offline and sync Also: Live data and payments
- Starts at
- Mid-level (also in the staff track)
- Reading time
- 15 min read
Build guide: 14 min - Builds on
- The five-step method
- Status
- Free
- Design photo backup and file syncUploads that can resume, sync by blocks, and edit conflicts.
- Topic
- Offline and sync Also: Feeds and media
- Starts at
- Mid-level (also in the staff track)
- Reading time
- 14 min read
Build guide: 18 min - Builds on
- Design a chat app
- Status
- Free
- Design a travel plans appFriends edit a trip together, even offline, and no change is lost without a sign.
- Topic
- Offline and sync
- Starts at
- Senior
- Reading time
- 15 min read
Build guide: 16 min - Builds on
- Design photo backup and file sync
- Status
- Free
- Design a public transport appA timetable that works offline, live delays on top, and careful use of location and battery.
- Topic
- Offline and sync Also: Live data and payments
- Starts at
- Senior
- Reading time
- 6 min read
- Builds on
- Design a stock ticker app
- Status
- Free teaser
This topic also appears in
The main topic of these case studies is a different one. Each one still teaches part of this topic.
- Design a news feedPaging, optimistic writes (show a change first), and keeping the cache fresh.
- Topic
- Feeds and media Also: Offline and sync
- Starts at
- Mid-level
- Reading time
- 15 min read
Build guide: 10 min - Builds on
- Design a chat app
- Status
- Free
- Design a hotel or ride booking appHolds, server time, payments, and search.
- Topic
- Live data and payments Also: Offline and sync
- Starts at
- Mid-level (also in the staff track)
- Reading time
- 15 min read
Build guide: 18 min - Builds on
- Design a chat app
- Status
- Free
- Design an analytics SDKSending events in batches, saving them on the device, privacy, and versions.
- Topic
- SDKs and libraries Also: Offline and sync
- Starts at
- Senior (also in the staff track)
- Reading time
- 14 min read
Build guide: 18 min - Builds on
- Design a chat app
- Status
- Free
Where these cases sit on the learning map
The blue boxes are in this topic. The boxes above them are the pages to read first. See the whole map.
- Case study
- Free teaser
- Guide
- In this topic
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