Convex Create Component

Create reusable Convex components with clear boundaries and a small app-facing API.

When to Use

• Creating a new Convex component in an existing app
• Extracting reusable backend logic into a component
• Building a third-party integration that should own its own tables and workflows
• Packaging Convex functionality for reuse across multiple apps

When Not to Use

• One-off business logic that belongs in the main app
• Thin utilities that do not need Convex tables or functions
• App-level orchestration that should stay in convex/
• Cases where a normal TypeScript library is enough

Workflow

1. Ask the user what they are building and what the end goal is. If the repo already makes the answer obvious, say so and confirm before proceeding.
2. Choose the shape using the decision tree below and read the matching reference file.
3. Decide whether a component is justified. Prefer normal app code or a regular library if the feature does not need isolated tables, backend functions, or reusable persistent state.
4. Make a short plan for:
   • what tables the component owns
   • what public functions it exposes
   • what data must be passed in from the app (auth, env vars, parent IDs)
   • what stays in the app as wrappers or HTTP mounts
5. Create the component structure with convex.config.ts, schema.ts, and function files.
6. Implement functions using the component's own ./_generated/server imports, not the app's generated files.
7. Wire the component into the app with app.use(...). If the app does not already have convex/convex.config.ts, create it.
8. Call the component from the app through components.<name> using ctx.runQuery, ctx.runMutation, or ctx.runAction.
9. If React clients, HTTP callers, or public APIs need access, create wrapper functions in the app instead of exposing component functions directly.
10. Run npx convex dev and fix codegen, type, or boundary issues before finishing.

Choose the Shape

Ask the user, then pick one path:

Read exactly one reference file before proceeding.

Default Approach

Unless the user explicitly wants an npm package, default to a local component:

• Put it under convex/components/<componentName>/
• Define it with defineComponent(...) in its own convex.config.ts
• Install it from the app's convex/convex.config.ts with app.use(...)
• Let npx convex dev generate the component's own _generated/ files

Component Skeleton

A minimal local component with a table and two functions, plus the app wiring.

// convex/components/notifications/convex.config.ts
import { defineComponent } from "convex/server";

export default defineComponent("notifications");

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

export default defineSchema({
  notifications: defineTable({
    userId: v.string(),
    message: v.string(),
    read: v.boolean(),
  }).index("by_user", ["userId"]),
});

// convex/components/notifications/lib.ts
import { v } from "convex/values";
import { mutation, query } from "./_generated/server.js";

export const send = mutation({
  args: { userId: v.string(), message: v.string() },
  returns: v.id("notifications"),
  handler: async (ctx, args) => {
    return await ctx.db.insert("notifications", {
      userId: args.userId,
      message: args.message,
      read: false,
    });
  },
});

export const listUnread = query({
  args: { userId: v.string() },
  returns: v.array(
    v.object({
      _id: v.id("notifications"),
      _creationTime: v.number(),
      userId: v.string(),
      message: v.string(),
      read: v.boolean(),
    })
  ),
  handler: async (ctx, args) => {
    return await ctx.db
      .query("notifications")
      .withIndex("by_user", (q) => q.eq("userId", args.userId))
      .filter((q) => q.eq(q.field("read"), false))
      .collect();
  },
});

// convex/convex.config.ts
import { defineApp } from "convex/server";
import notifications from "./components/notifications/convex.config.js";

const app = defineApp();
app.use(notifications);

export default app;

// convex/notifications.ts  (app-side wrapper)
import { v } from "convex/values";
import { mutation, query } from "./_generated/server";
import { components } from "./_generated/api";
import { getAuthUserId } from "@convex-dev/auth/server";

export const sendNotification = mutation({
  args: { message: v.string() },
  returns: v.null(),
  handler: async (ctx, args) => {
    const userId = await getAuthUserId(ctx);
    if (!userId) throw new Error("Not authenticated");

    await ctx.runMutation(components.notifications.lib.send, {
      userId,
      message: args.message,
    });
    return null;
  },
});

export const myUnread = query({
  args: {},
  handler: async (ctx) =>