Anyone know of any examples of cool cases where websockets have been used? (Maybe other than games.) I feel like in most cases I see them used the latency gained is basically added back with bloat in other parts.
My use case was I wanted to transfer a PDF to an Android-based tablet but in the moment didn't want to log into my email. I couldn't think of any quick, easy, and cross-platform solutions so I decided to write the service.
It's built on socket.io which is a godsend for websockets because it automatically handles so much grunt work and your app just works.
The client-side code is generally very simple. A dashboard opens a websocket and attaches a handler which parses the message (all our payloads are JSON), then routes the update to the right bit of the UI. We wrote a thin wrapper round the browser websocket API to handle disconnections. We wrote server-side libraries to support our patterns of use.
I initially did a bunch of developer-facing dashboards using server-sent events, because they're slightly easier to work with. However, websockets have a significant advantage over SSE: you can have a lot more of them open at once. Browsers will limit you to a few (six?) connections per origin, including long-lived SSE connections, whereas you can have dozens or hundreds of websockets open [1]. If you are serving lots of different dashboards off a single server, you rapidly get to the point where this matters!
[1] https://stackoverflow.com/questions/26003756/is-there-a-limi...
Whether this qualifies as a 'cool' case is probably subjective, but it is important in practice.
I'm not sure if it's as widespread, but many exchanges use websockets in the front-end to make the same data available to the site users without frequent polling.
Couldn't find the Show HN just now but searching "subspace" comments might reveal it ("this reminds me of subspace"). I always wanted to look more into the approach.
1. Sports events streaming live updates (see https://ausopen.com/live-scores, we are streaming live scores for the Tennis Australian Open right now). Companies like Toyota even use us to facilitate engineers tweaking the performance characteristics of their cars in realtime remotely.
2. Edtech - we have numerous customers using us to drive live classroom environments, think shared white boards, collaborative tests, presence, teacher engagement. You may have used Codewars in the past, that uses Ably under the hood for example, https://www.codewars.com/.
3. Live screen sharing and collaborative applications. You may have used the amazing Tuple.app, that uses Ably under the hood https://tuple.app/.
4. Collaborative and live web and mobile SaaS applications, where changes need to occur concurrently, notifications need to be presented, and other realtime updates are needed in the interface. You've probably heard of Hubspot, they use Ably under the hood to power their collaborative and live features, https://hubspot.com
5. Developer infrastructure and platforms that need realtime capabilities at scale. You have probably come across Split, the leading feature flag company backed by Atlassian and Microsoft. They use Ably under the hood to power billions of feature flag updates in realtime each month. https://www.split.io/
6. Financial market data - typically streaming updates to thousands or millions of subscribers with very low latency, and sometimes using features like Deltas (https://ably.com/documentation/realtime/channels/channel-par...) to keep bandwidth & latency as low as possible.
I could keep going, but I hope that gives you the idea, realtime is not just for Christmas or for Games :)
Matt, co-founder of ably.com