Freemium AI SaaS: ship a free → paid funnel without a backend

The problem

Freemium for AI is harder than freemium for regular SaaS, because every action your free users take costs you real money - tokens, GPU time, API fees. A free tier with no enforcement bleeds margin.

You also need the conversion mechanics: track usage in real time, show users how close they are to the limit, fire upgrade nudges at 80%, hard-block at 100%, expose a billing portal at the right moment.

Building all of that in-house - counter tables, period resets, dashboards, webhooks, an end-user portal - is weeks of work that competes with the actual product.

The solution

Define two plans: free (hard caps) and pro (high or no caps). When a user signs up, call vevee.upsertSubscription(userId, "plan_free"). When they pay, switch to plan_pro.

Gate every AI call with vevee.reserve/commit/release. Free users get a clean limit_reached when they hit their cap; your UI catches the error code and shows an upgrade prompt.

Wire webhooks to fire at 80% threshold for upgrade nudges. Use the pk_live_ public key to render "X renders left this month" client-side without a server roundtrip.

Example

Free users hit a clean 429 at quota. The error code drives the upgrade prompt. Paid users keep going.

import { createClient, VeveeError } from "@vevee/sdk";

const vevee = createClient({ apiKey: process.env.VEVEE_KEY! });

export async function generate(userId: string, prompt: string) {
  try {
    await vevee.track(userId, "image.render", 1);
    return await callFlux(prompt);
  } catch (err) {
    if (err instanceof VeveeError && err.code === "limit_reached") {
      // Free user hit their cap - show upgrade prompt in the UI
      throw new UpgradeRequiredError("You have reached your free plan limit");
    }
    throw err;
  }
}

// On Stripe checkout success:
export async function onCheckoutComplete(userId: string) {
  await vevee.upsertSubscription({
    userId,
    planId: "plan_pro",
  });
}

Frequently asked questions

Other use cases