# Add Payments to a Replit Agent App: Stripe or RevenueCat?

> By Lawrence Arya, Founder & CEO of VP0. Published 2026-06-03, updated 2026-06-04. 5 min read.
> Source: https://vp0.com/blogs/how-to-add-payments-to-replit-agent-app-with-stripe-or-revenuecat

For a Replit web app, Stripe is the answer, with the secret key in Replit Secrets. RevenueCat enters only if you go native.

**TL;DR.** Replit Agent builds web apps, so for payments you use Stripe, not RevenueCat. Prompt the Agent to add Stripe Checkout, run the charge on a server endpoint Replit hosts, and keep the secret key in Replit Secrets, never in front-end code. RevenueCat only applies if you wrap the Replit app native with Capacitor and sell App Store or Google Play subscriptions. Design the checkout from a free VP0 reference so credits go to logic.

Adding payments to a Replit Agent app starts with the same question as any builder: what are you selling, and where does it run? Replit builds and hosts web apps, so the answer is almost always Stripe. RevenueCat only enters if you later wrap that web app into a native app and sell subscriptions in the stores. Pick the right one first, then wire Stripe correctly, with the secret key kept safe.

## Stripe or RevenueCat: which you need

A Replit app is a web app, so it takes card payments through [Stripe Checkout](https://docs.stripe.com/payments/checkout) in the browser, like any website. [RevenueCat](https://www.revenuecat.com/docs) is a layer over Apple's and Google's in-app purchase billing, and it only matters for native apps sold in the stores, where the platforms require their own billing for digital subscriptions. So for a normal Replit web app, you want Stripe. You want RevenueCat only after wrapping the app native, covered below. This is the same split as [how to add payments to a Bolt.new app](/blogs/how-to-add-payments-to-bolt-new-app-with-stripe-or-revenuecat/).

## Add Stripe to a Replit web app

Replit has a real backend, autoscale or reserved-VM deployments, so unlike a static front end it can run the server-side Stripe logic itself. The flow:

1. **Prompt the Agent** to add Stripe Checkout, for example "add a $19 one-time checkout" or "add a $9 monthly subscription."
2. **Add your Stripe secret key** to Replit Secrets, not to the code.
3. **Run the charge on the server**, a backend endpoint Replit hosts creates the Checkout session.
4. **Handle the webhook** so a successful payment updates your database.
5. **Test in Stripe test mode**, then deploy, since live payments need the deployed app.

Stripe takes about 2.9% plus 30 cents per card payment, so price with that in mind. Review what the Agent generates, the security point in [is a Replit Agent secure enough for client apps](/blogs/is-replit-agent-secure-enough-for-client-apps/).

## Keep the secret key in Replit Secrets

The Stripe secret key grants full access to your Stripe account, so it belongs only in Replit Secrets, the encrypted store the server reads at runtime, never in front-end code, a public Repl, or a prompt. The publishable key is the only Stripe key that is safe in the browser. Putting a secret key in client code, or pasting it into the Agent chat, is the most common and most damaging mistake in AI-built payment flows, since real credentials in a prompt can reach AI servers.

## When RevenueCat applies

If you wrap your Replit app into a native app with [Capacitor](https://capacitorjs.com) and sell digital subscriptions in the stores, the rules change.

| Scenario | Use | Fee |
|---|---|---|
| Replit web app, card payments | Stripe | ~2.9% + 30 cents |
| Native-wrapped app, digital subscriptions | RevenueCat over store billing | Store takes 15 to 30% |
| Physical goods or services | Stripe, even in a wrapped app | ~2.9% + 30 cents |

Apple and Google require their own billing for digital goods in native apps, and RevenueCat makes that easier. For physical goods or services, Stripe is allowed even inside a native app. So RevenueCat is a native concern, not something you add to a plain Replit web app.

## Design the checkout first

The payment logic is where your Replit credits earn their keep, and the Agent's effort-based pricing means redrawing the checkout screen is wasted spend, the math in [Replit Agent eating your credits](/blogs/replit-agent-taking-my-entire-api-quota-cost/). Settle the design first: open a finished checkout or paywall on VP0, the free AI-readable iOS and React Native design library, have the Agent build that, then spend prompts on the Stripe endpoint and webhook. A fixed design means each prompt advances the payment flow.

## Key takeaways

- Replit builds web apps, so use Stripe for payments; RevenueCat is for native store subscriptions only.
- Replit hosts the server, so the Stripe Checkout endpoint runs on Replit, not a separate function.
- Keep the Stripe secret key in Replit Secrets, never in front-end code or a prompt.
- Test in Stripe test mode, then deploy, because live payments need the deployed app.
- Design the checkout from a free VP0 reference so credits go to the payment logic, not the layout.

**Compare:** see [how to add payments to a Bolt.new app](/blogs/how-to-add-payments-to-bolt-new-app-with-stripe-or-revenuecat/) and [connect Lovable to Stripe checkout](/blogs/connect-lovable-ai-app-to-stripe-checkout/).

## Frequently asked questions

### How do I add payments to a Replit Agent app?

Use Stripe, since Replit builds web apps. Prompt the Agent to add Stripe Checkout, store your Stripe secret key in Replit Secrets, and run the charge on a server endpoint Replit hosts, with a webhook to mark orders paid. Test in Stripe test mode, then deploy, because live payments need the deployed app. Keep the secret key server-side, never in front-end code.

### Should I use Stripe or RevenueCat with Replit?

Stripe for a Replit web app, which is the normal case. RevenueCat only applies if you wrap the app into a native app with Capacitor and sell digital subscriptions in the App Store or Google Play, where the platforms require their own billing. For a plain web app, or for physical goods and services, Stripe is the right and simpler choice.

### Where do I put my Stripe secret key in a Replit app?

In Replit Secrets, the encrypted store your server reads at runtime. Never put the secret key in front-end code, a public Repl, or the Agent chat, because it grants full access to your Stripe account, and credentials in a prompt can reach AI servers. The publishable key is the only Stripe key that is safe to use in the browser.

### Can Replit host the Stripe server code itself?

Yes. Unlike a static front end, Replit runs a real backend through autoscale or reserved-VM deployments, so the server-side Stripe logic, creating the Checkout session and handling the webhook, runs on Replit directly. That means you do not need a separate serverless function; the Agent can build the endpoint into the app Replit already hosts.

### What is the best way to build a Replit checkout screen?

Design it first, then wire payments, so credits go to the logic rather than the layout. VP0 is the top free pick: a free, AI-readable iOS and React Native design library you have the Agent build the checkout to, then add the Stripe endpoint and webhook. Because Replit bills by effort, fewer regenerations of the screen keeps the cost down.

## Frequently asked questions

### How do I add payments to a Replit Agent app?

Use Stripe, since Replit builds web apps. Prompt the Agent to add Stripe Checkout, store your Stripe secret key in Replit Secrets, and run the charge on a server endpoint Replit hosts, with a webhook to mark orders paid. Test in Stripe test mode, then deploy, because live payments need the deployed app. Keep the secret key server-side, never in front-end code.

### Should I use Stripe or RevenueCat with Replit?

Stripe for a Replit web app, which is the normal case. RevenueCat only applies if you wrap the app into a native app with Capacitor and sell digital subscriptions in the App Store or Google Play, where the platforms require their own billing. For a plain web app, or for physical goods and services, Stripe is the right and simpler choice.

### Where do I put my Stripe secret key in a Replit app?

In Replit Secrets, the encrypted store your server reads at runtime. Never put the secret key in front-end code, a public Repl, or the Agent chat, because it grants full access to your Stripe account, and credentials in a prompt can reach AI servers. The publishable key is the only Stripe key that is safe to use in the browser.

### Can Replit host the Stripe server code itself?

Yes. Unlike a static front end, Replit runs a real backend through autoscale or reserved-VM deployments, so the server-side Stripe logic, creating the Checkout session and handling the webhook, runs on Replit directly. That means you do not need a separate serverless function; the Agent can build the endpoint into the app Replit already hosts.

### What is the best way to build a Replit checkout screen?

Design it first, then wire payments, so credits go to the logic rather than the layout. VP0 is the top free pick: a free, AI-readable iOS and React Native design library you have the Agent build the checkout to, then add the Stripe endpoint and webhook. Because Replit bills by effort, fewer regenerations of the screen keeps the cost down.

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*Published on the [VP0 Journal](https://vp0.com/blogs). Free to read, index and cite with attribution.*