Unlocking Backend Simplicity: Building Scalable Apps with Convex

Building scalable, efficient applications can be challenging right ? Specially you have less time or in a hackathon. What if I told you there’s a backend solution that can simplify this process?

Recently I was working on a project where I used the Convex backend for the first time and guess what, it feels simply awesome.

Let’s build a backend function using Convex

• Convex provides built-in user authentication with ctx.auth.getUserIdentity(), making it easy to check if a user is logged in. If the user is not authenticated, we throw a ConvexError, which automatically returns an “Unauthorized” response to the client.
  

  const identity = await ctx.auth.getUserIdentity();

  if (!identity) {

    throw new ConvexError("Unauthorized");

  }

• With Convex, database queries are simplified. Using ctx.db.query, we retrieve the conversation by filtering for a match with the provided conversation ID.
  

  const conversation = await ctx.db.query("conversations")

    .filter((q) => q.eq(q.field("_id"), args.conversationId))

    .first();

  if (!conversation) {

    throw new ConvexError("Conversation not found");

  }

• Convex allows us to query all users with ctx.db.query("users").collect(). We then use filter to select only users who are participants in the conversation. Convex’s built-in data retrieval methods make it easier to manage collections without dealing with manual database connection handling.
  

  const users = await ctx.db.query("users").collect();

  const groupMembers = users.filter((user) => conversation.participants.includes(user._id));

• That’s all. Since Convex handles response management, simply returning groupMembers from the function sends the data to the client.
  

  return groupMembers;

And here is the overall simplified explanation diagram how convex process the backend -