- Learn AWS
- Architecture
- Live updates
Architecture pattern
AWS Live updates architecture
when the server has to push, not be asked
A WebSocket API keeps the connection open so the server can send without being asked, and bills per message rather than per hour. Redis holds the state everyone is watching, with counters and sorted sets for ranking and pub/sub to tell the other handlers something changed.
What it runs through
In the order a request or a record moves through it. Each one links to the page that explains it.
- Web clientBrowser / web client
- API Gateway (WebSocket)Amazon API Gateway — WebSocket API
- LambdaAWS Lambda
- ElastiCache RedisAmazon ElastiCache for Redis
Signals in a brief that point here
Phrases that, when you meet them in a scenario, mean this shape rather than another. They are the tell, and they are what an exam question is built around.
- “without polling”
- “every participant sees it immediately”
- “two-way connection”
- “live”
- “collaborative”
What it costs you
Connection state is now yours to track, and anything durable still needs a real database behind the cache.
Every shape has one. A design decision with no stated downside is usually a decision nobody has finished making.
Learn the services in it
- AWS API GatewayA managed front door for APIs: REST, HTTP and WebSocket APIs that take each call, check who is calling, throttle it, and pass it to Lambda, another service or any HTTP backend.
- AWS LambdaRuns your code in response to events, with no servers to manage. You pay per request and by the millisecond, and a run lasts 15 minutes at most.
- AWS ElastiCacheA managed in-memory cache, Valkey, Redis OSS or Memcached, that answers repeated reads from memory so the database behind it does less.
Shapes it is easily confused with
These run through some of the same services, which is exactly why a brief that fits one can look like it fits another.
Now build it from a brief
Reading a shape and producing one from a scenario that never names a service are different skills, and the exam asks for the second. The scenarios give you the brief; you draw the architecture and it is scored against what the brief requires.