10 Essential Tips for New Convex Developers: Build Faster, Smarter, and Error-Free

Welcome to Convex. If you are reading this, you are likely stepping into a new paradigm of full-stack development—one that replaces the glue code, ORMs, and manual infrastructure management of the past with a real-time, type-safe, and serverless backend.

While Convex is designed to be intuitive, especially for React and TypeScript developers, shifting your mindset from a traditional REST or GraphQL backend to Convex's "backend-as-a-function" model can have a learning curve. It is easy to accidentally carry over habits from legacy SQL or NoSQL workflows that fight against Convex's reactivity model rather than leveraging it.

To help you hit the ground running, we have compiled 10 essential tips. These are the insights that seasoned Convex developers wish they had known on day one—practical advice to help you avoid common pitfalls, optimize performance, and maintain a clean, scalable codebase.

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1. Embrace End-to-End Type Safety from Day One

One of Convex’s most powerful features is its ability to share types seamlessly between your backend database and your frontend client. Unlike traditional setups where you might manually sync TypeScript interfaces or run codegen scripts, Convex handles this automatically.

The Strategy: Don't write manual types for your API responses. Instead, define your schema in convex/schema.ts using the v validator. When you run npx convex dev, Convex generates an api object in convex/_generated/api.ts.

How to do it: Use this generated API object in your React hooks. This gives you immediate autocomplete and error checking.

// convex/schema.ts
import { defineSchema, defineTable } from "convex/server";
import { v } from "convex/values";

export default defineSchema({
  tasks: defineTable({
    text: v.string(),
    isCompleted: v.boolean(),
  }),
});

Common Pitfall: Ignoring the generated types and casting responses as any or manually defining interfaces on the client. This breaks the link between your database and UI, negating one of Convex's biggest productivity boosters.

2. Master Queries for Read-Only Data, Mutations for Writes

Convex makes a strict distinction between reading and writing data, and respecting this boundary is critical for the reactivity engine to work.

The Strategy:

• Queries (db.query): Use these for reading data. They are "pure" functions, cacheable, and automatically reactive.
• Mutations (db.insert, db.update, db.delete): Use these for writing data. They run as transactions.

How to do it: If you need to fetch a list of items to display on the screen, write a query. If the user clicks a button to save an item, write a mutation.

// convex/tasks.ts
import { query, mutation } from "./_generated/server";

// Valid: Reading data
export const get = query({
  handler: async (ctx) => {
    return await ctx.db.query("tasks").collect();
  },
});

// Valid: Writing data
export const create = mutation({
  handler: async (ctx, args) => {
    // mutations can also read!
    const existing = await ctx.db.query("tasks").first();
    await ctx.db.insert("tasks", { text: args.text, isCompleted: false });
  },
});

Common Pitfall: Using a mutation to fetch data because you "might" need to update it later, or using a query to perform side effects (which isn't allowed). Misusing these leads to inefficient data loading and loss of real-time updates.

3. Design Your Schema with defineTable for Scalability

Convex is a document-relational database. It offers the flexibility of JSON documents with the structure and relationships of a relational database.

The Strategy: Even though you can start without a schema, you should use defineTable immediately. This enforces data consistency and enables the type generation mentioned in Tip #1.

How to do it: Plan your data model. If you have "Users" and "Posts," create two separate tables and link them via IDs, rather than nesting all posts inside a user document.

Common Pitfall: Treating Convex like a pure NoSQL store and creating deeply nested arrays of objects. While possible, this makes updating specific items difficult and can hurt performance. Keep your documents relatively flat and use relationships.

4. Understand and Leverage Real-time Reactivity

This is the "magic" of Convex. You do not need useEffect, manual subscriptions, or WebSocket handling code.

The Strategy: Trust the system. When you use the useQuery hook in your React component, it creates a subscription. If the underlying data in the database changes (via a mutation), Convex pushes the new data to the client, and your component re-renders automatically.

How to do it:

import { useQuery } from "convex/react";
import { api } from "../convex/_generated/api";

function TaskList() {
  // This list updates automatically when the DB changes!
  const tasks = useQuery(api.tasks.get); 

  if (!tasks) return <div>Loading...</div>;

  return <ul>{tasks.map(t => <li key={t._id}>{t.text}</li>)}</ul>;
}

Common Pitfall: Trying to manually "refresh" data after a mutation. New developers often write code to re-fetch queries after a generic "save" action. With Convex, you fire the mutation and forget it; the query updates itself.

5. Secure Your Functions with ctx.auth and Input Validation

Because Convex functions are exposed directly to the client, you must treat them as public API endpoints.

The Strategy: Never trust the client. Always validate who is calling the function and what data they are sending.

How to do it:

1. Authentication: Use ctx.auth.getUserIdentity() to check if a user is logged in.
2. Validation: Use the args object with v validators to ensure the inputs are correct types.

export const secureDelete = mutation({
  args: { taskId: v.id("tasks") },
  handler: async (ctx, args) => {
    const user = await ctx.auth.getUserIdentity();
    if (!user) throw new Error("Unauthenticated");

    const task = await ctx.db.get(args.taskId);
    if (task.userId !== user.subject) throw new Error("Unauthorized");

    await ctx.db.delete(args.taskId);
  },
});

Common Pitfall: Checking authentication on the frontend only (e.g., hiding a button) but failing to enforce the check inside the Convex mutation.

6. Optimize Queries with Indexing

By default, ctx.db.query("tableName") performs a full table scan. This is fine for prototyping with 100 records, but it will become a bottleneck as your app scales.

The Strategy: Identify your most common access patterns (e.g., "Get all tasks for a specific user") and create indexes for them in schema.ts.

How to do it:

// schema.ts
export default defineSchema({
  tasks: defineTable({ ... })
    .index("by_user", ["userId"]) // Index for querying by userId
});

// tasks.ts
export const getByUser = query({
  handler: async (ctx, args) => {
    return await ctx.db
      .query("tasks")
      .withIndex("by_user", (q) => q.eq("userId", args.userId))
      .collect();
  },
});

Common Pitfall: Waiting until the app feels slow to add indexes. Adding basic indexes for foreign keys (like userId or teamId) is a best practice from the start.

7. Batch Database Operations for Efficiency

Network latency is often the biggest performance killer. Sending 10 separate mutation requests from the client to delete 10 items is inefficient.

The Strategy: Convex mutations are transactional. You can perform multiple database operations (insert, update, delete) inside a single mutation function call.

How to do it: Create a specific mutation for the bulk operation.

export const deleteMultiple = mutation({
  args: { taskIds: v.array(v.id("tasks")) },
  handler: async (ctx, args) => {
    // All of these happen in a single transaction
    for (const id of args.taskIds) {
      await ctx.db.delete(id);
    }
  },
});

Common Pitfall: Looping over an array on the client and calling mutate() inside the loop. This causes a "waterfall" of network requests.

8. Leverage Local Development & Debugging

You don't need to deploy to the cloud to test your backend logic.

The Strategy: Keep npx convex dev running in your terminal. This spins up a local development environment (or syncs to a dev deployment) that updates instantly as you save files.

How to do it: Use console.log inside your Convex functions (in convex/myFunction.ts). The logs will appear directly in your terminal where npx convex dev is running, as well as in your browser's console (a unique feature of Convex).

Common Pitfall: Flying blind. If a query isn't returning what you expect, log the intermediate variables inside the query handler to inspect the data flow immediately.

9. Organize Your Convex Functions for Maintainability

Convex creates an API based on your file structure in the convex/ folder. As your app grows, a single convex/api.ts file becomes unmanageable.

The Strategy: Modularize your backend logic by feature or domain.

How to do it:

• convex/users.ts
• convex/messages.ts
• convex/stripe.ts

You can also create a convex/lib/ or convex/helpers/ folder for internal utility functions that are not exposed to the client.

Common Pitfall: Dumping all logic into convex/myFunctions.ts or copying and pasting the same permission checks into every single mutation. Extract common logic into helper functions.

10. Monitor & Troubleshoot with the Convex Dashboard

The Convex Dashboard is not just for billing; it is a powerful observability tool.

The Strategy: Familiarize yourself with the dashboard early. It provides a Data Browser to view and edit your database content manually (invaluable for seeding or fixing test data) and a Logs view to see production errors.

How to do it: If something works locally but fails in production, go to the Dashboard > Logs. You can filter by function name or request ID to pinpoint exactly where the logic failed.

Common Pitfall: Ignoring the dashboard until there is a critical outage. Periodically checking your function execution times in the dashboard can help you spot unoptimized queries before they become problems.

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Conclusion

Convex significantly lowers the barrier to entry for building robust, full-stack applications. It handles the hard parts—real-time syncing, caching, and database management—so you can focus on your product.

By following these 10 tips, you move beyond "making it work" to building a backend that is secure, performant, and easy to maintain. Embrace the type safety, respect the reactivity model, and keep your schema clean. Your future self (and your users) will thank you.

Ready to start building? Check out the official Convex documentation to dive deeper.