convex-billing

SKILL.md

Add billing / payments

Wire Stripe to Convex using @convex-dev/stripe: a checkout action, an httpAction webhook registered by the component (signature-verified automatically), subscription state stored in the component's tables, and server-side gating via a query.

Workflow

Install the component: npm install @convex-dev/stripe.

Create convex/convex.config.ts:
import { defineApp } from 'convex/server';
import stripe from '@convex-dev/stripe/convex.config.js';
const app = defineApp();
app.use(stripe);
export default app;

Store Stripe keys in Convex env (use the env micro power): STRIPE_SECRET_KEY (sk_test_… / sk_live_…) and STRIPE_WEBHOOK_SECRET (whsec_…).

Create convex/http.ts to register the webhook route (the component handles signature verification automatically):
import { httpRouter } from 'convex/server';
import { components } from './_generated/api';
import { registerRoutes } from '@convex-dev/stripe';
const http = httpRouter();
registerRoutes(http, components.stripe, { webhookPath: '/stripe/webhook' });
export default http;

Create convex/billing.ts with a checkout action and a subscription-gate query:
import { action, query } from './_generated/server';
import { components } from './_generated/api';
import { StripeSubscriptions } from '@convex-dev/stripe';
import { v } from 'convex/values';
const stripeClient = new StripeSubscriptions(components.stripe, {});
export const createSubscriptionCheckout = action({
  args: { priceId: v.string() },
  returns: v.object({ sessionId: v.string(), url: v.union(v.string(), v.null()) }),
  handler: async (ctx, args) => {
    const identity = await ctx.auth.getUserIdentity();
    if (!identity) throw new Error('Not authenticated');
    const customer = await stripeClient.getOrCreateCustomer(ctx, { userId: identity.subject, email: identity.email, name: identity.name });
    return await stripeClient.createCheckoutSession(ctx, { priceId: args.priceId, customerId: customer.customerId, mode: 'subscription', successUrl: `${process.env.SITE_URL ?? 'http://localhost:3000'}/?success=true`, cancelUrl: `${process.env.SITE_URL ?? 'http://localhost:3000'}/?canceled=true`, subscriptionMetadata: { userId: identity.subject } });
  },
});
export const isSubscribed = query({
  args: {},
  returns: v.boolean(),
  handler: async (ctx) => {
    const identity = await ctx.auth.getUserIdentity();
    if (!identity) return false;
    const subscriptions = await ctx.runQuery(components.stripe.public.listSubscriptionsByUserId, { userId: identity.subject });
    return subscriptions.some((sub) => sub.status === 'active' || sub.status === 'trialing');
  },
});

Run npx convex dev --once — it will install the component and push the functions. Verify output shows ✔ Installed component stripe.

In Stripe Dashboard → Webhooks: add endpoint https://<deployment>.convex.site/stripe/webhook, subscribe to checkout.session.completed, customer.subscription.*, invoice.*, payment_intent.*. Copy the signing secret as STRIPE_WEBHOOK_SECRET.

Rules

Use @convex-dev/stripe (npm: @convex-dev/stripe@^0.1.4) — it handles webhook signature verification internally via registerRoutes; do NOT write a manual constructEvent webhook.

Stripe keys live in Convex env (use the env micro power): STRIPE_SECRET_KEY and STRIPE_WEBHOOK_SECRET.

Gate on server-stored subscription state via isSubscribed query (reads component tables), not client claims.

convex/convex.config.ts must import from '@convex-dev/stripe/convex.config.js' (not .ts) — the .js extension is required by the Convex bundler.