Building a Chat Application: Architecture Decisions That Actually Matter

Building a real-time chat application taught us that the hard problems in messaging apps aren't the chat bubbles — they're what happens when the network isn't perfect.

Choosing a real-time transport

WebSockets (via something like Socket.IO) give you low-latency, persistent connections ideal for chat, but you need a plan for reconnection when a mobile client loses signal mid-conversation — which happens constantly on mobile networks in Nepal.

Message delivery guarantees

"Did the message actually send?" is harder than it sounds. We track message state client-side (sending, sent, delivered, read) and reconcile it against server acknowledgment, so a flaky connection doesn't silently drop a message the sender assumed went through.

Scaling group chats

One-to-one chat and group chat aren't the same problem at scale. Fanning out a message to a hundred-person group needs a different delivery strategy than a two-person conversation, or your server ends up doing redundant work per message.

Media sharing without killing performance

Uploading and displaying images/media inline needs to happen without blocking the message stream — we process and compress media asynchronously so a large photo upload doesn't stall the rest of the conversation.

Push notifications: the unglamorous backbone

A chat app lives or dies on notification reliability. Getting push notifications right across web and mobile clients sharing one backend took more engineering effort than the actual chat UI.

Building something with real-time messaging at its core? Reach out — we've solved most of the annoying edge cases already.