# Bitcoin checkout on Replit Replit Agent builds web apps with an Express server and a Postgres database, and OpenReceive's Express package runs in them as is. Your app's own server code creates each Lightning invoice, the payment goes straight to your wallet, and payment attempts are stored in your app's Postgres database. There is no OpenReceive account, no API key and no background worker. Optional swaps let customers pay with **USDT, USDC, SOL, and ETH**. A swap provider you configure converts the payment to **BTC over Lightning**, and it settles into the same wallet. Available assets and networks depend on the provider. Use `@openreceive/*` 0.4.19 or newer. ## Before you start - A receive-only NWC code from your Lightning wallet ([get one](https://openreceive.org/get_a_nwc_code_to_receive_payments)). It can create invoices and read payments, but it cannot spend. - Optional: a swap provider code, for USDT, USDC, SOL and ETH ([set one up](https://openreceive.org/set_up_swap_provider)). Put both in the app's Secrets, never in the chat. Secrets reach your server code as environment variables, and Replit links them to the published app. ## Add checkout to your Replit app 1. Open **Tools** → **Secrets** → **New Secret**. Add `NWC_URI` with your wallet code, then, for swaps, `LSC_URI_PRIMARY` with your swap provider code. Replit already gives every app a Postgres database in `DATABASE_URL`. The Secrets tool with a new secret named NWC_URI 2. Send Replit Agent this prompt: ```text Add Bitcoin Lightning checkout to this app with OpenReceive. Download the directions with your terminal and follow them exactly: curl -fsSL https://openreceive.org/agent-directions/node/full.md NWC_URI and LSC_URI_PRIMARY are already set as this app's Secrets, and the server reads them from process.env. Do not ask me for them, and do not look for them, check them or print them. Mount the payment routes on the Express server and store payments in this app's Postgres database, through DATABASE_URL. Create OpenReceive's tables when the server starts (the schema SQL is idempotent), because a published Replit app gets its own production database. Use @openreceive packages 0.4.19 or newer. ``` Bitcoin only, with no swap provider? Then in the prompt, replace `NWC_URI and LSC_URI_PRIMARY are already set` with `I want Bitcoin only, with no swaps. NWC_URI is already set`. If Agent offers to switch from **Free** to **Power**, choose **Continue on Power**. Power can use paid credits. In our test, Agent on Free stopped partway through this setup, and on Power it finished in about 11 minutes. Replit Agent recommending Power mode, with a Continue on Power button The directions tell Agent how to map the three hooks onto your existing orders and how to render the checkout. Agent ends with "Setup is finished" and a link to try the checkout. This prompt is for apps with a Node server, which is what Replit Agent builds by default. If your app's server is Python, follow the [FastAPI](/guides/quickstart-fastapi.md) or [Django](/guides/quickstart-django.md) quickstart instead. ## Check it In Preview, place an order. Its checkout shows the payment methods. Pick Bitcoin to see a Lightning invoice in sats. If the app stops at start, read the Console: usually `NWC_URI` is missing from Secrets, or the code is not receive-only. Each swap has a minimum amount set by the provider, so on a small order some coins are greyed out and show their minimum. The OpenReceive checkout in Replit's Preview on a $7 order: Bitcoin, USDT, USDC and SOL, and ETH greyed out with a minimum amount of $20.22 Pay a small order from your wallet to see it settle: the checkout shows the payment as received, and `onPaid` marks the order paid. ## Publish 1. Select **Publish**. Under **Advanced settings**, keep **Autoscale**, and check that **Deployment secrets** lists `NWC_URI` (and `LSC_URI_PRIMARY`) with a link icon: Replit copies your Secrets into the published app. If you add a secret after publishing, check this list and republish. Under **Database settings**, **Set up your production database with your current development data** copies every row, test orders and their payment attempts included. Untick it only if the live shop needs none of that data and the app creates all its tables when it starts, as the starter does. Publishing settings: Autoscale, deployment secrets NWC_URI and LSC_URI_PRIMARY linked to the app's Secrets, and the database settings 2. Select **Publish** and wait for "Your project is live", about four minutes. Replit's message: Congratulations! Your project is live. 3. Open the `replit.app` address, place an order and pick Bitcoin. A Lightning invoice appears. The published shop's checkout showing a Lightning invoice with its QR code The published app uses its own production database, separate from the one you build with. Replit can start it with a copy of your development data, and the server also creates OpenReceive's tables there on its first start. ## Start from the starter The [Express + Postgres starter](https://github.com/OpenReceive/openreceive/tree/master/examples/express-postgres-starter) is a one-product shop with checkout already wired, set up for Replit Autoscale. Its `replit.md` tells Agent how the payment code fits together, so you can ask for products, pages and design and keep checkout working. The README shows how to copy it into a repository of your own and import it into Replit. ## How it runs on Replit - **No worker or cron job.** Each request to the payment routes also checks the wallet for settled invoices, through a lock in your database. A payer who closes the tab is settled on the next request, so Autoscale can scale to zero between visits. - **Reserved VM, optionally.** A Reserved VM never sleeps, so it can also run the optional notifications worker, which settles a payment the moment the wallet reports it. Autoscale does not need it. - **Direct database connection.** `DATABASE_URL` points at Postgres 16 with no pooler, so `pg` and the usual ORMs work unchanged. Do not force TLS in code: the development database does not use it and the production database requires it, and each one's URL already says which. - **Port and health check.** The server listens on `0.0.0.0`. When you publish, Replit requests the home page and fails the publish if it takes more than 5 seconds, so keep slow work off `/`. - **Rate limiting.** Keep `rateLimiting: true` with `app.set("trust proxy", 1)`. Replit's proxy sets `x-forwarded-for`, so the limit applies per payer. - **Keep order pages reachable.** A payer with a swap in progress comes back through the order's own page to claim a refund. Keep the swap's payment hash too, and pass it back to the checkout (`resume-payment-hash` on the element, `resumePaymentHash` in React): without it, the page opens on the payment methods instead of the refund. See [swap refunds](/guides/swap-refunds.md). More detail: [Express quickstart](/guides/quickstart-node.md), [Payment storage](/guides/storage.md), [Security](/guides/security.md).