How to take payments and deliver digital products

You’ve finished a workbook and want to sell it for €19. Someone should be able to visit your website, pay and open the file without waiting for you to send an email.

That’s the purchase flow we’re building here. The workbook and price are fictional; you can use the same approach for a template, course or downloadable kit. AI can handle much of the product setup once you connect it to the right tools.

Choose who handles the sale

Your website can stay on your own domain with any of these providers. The bigger difference is who handles the transaction and what you need to arrange around it.

Polar and Lemon Squeezy act as the merchant of record: they sell to the customer and handle transaction sales taxes. You still make and support the product and handle your own business’s accounting and income-tax obligations. Their explanations cover the division of responsibilities: Polar and Lemon Squeezy.

With standard Stripe Payments, your business is the merchant of record. Stripe also offers a separate Managed Payments service; check its eligibility and coverage if that’s the route you want.

We use Polar for Practical Dept’s paid downloads. Keeping payment and file access together suits this shop. Before choosing for yours, compare the current fees, payout timing and product restrictions as well as the features.

Check that you can use the provider

Check your seller country, business type and product against the provider’s requirements before building the integration. Account approval is a separate step from testing a checkout.

For a Serbian business, both Polar and Lemon Squeezy list Serbia for payouts. Polar’s Stripe Connect payout coverage is different from standalone Stripe Payments availability. Check the relevant list for the account you’re opening.

Then read Polar’s acceptable-use policy or Lemon Squeezy’s product rules. A downloadable course and a service you perform for a client can be treated differently.

Give AI a complete product brief

ChatGPT or Claude can help you write the listing before you connect any accounts. Give it the actual contents and ask for a title, description, contents list and support FAQ. Read the result against your files so the listing only promises what you deliver.

For the setup itself, prepare the product name, price, currency, final file and support address. Check how the provider calculates and displays tax, then make your product page match the checkout. A brief such as “Weekly Planning Workbook, €19 once, EUR, weekly-planning-v1.zip” gives the agent something specific to work with.

To create records in your account, the AI needs a connected tool. MCP is one way an AI app calls those tools. A chat with no account connection can prepare the work, but it can’t save your product to Polar or Stripe.

Connect Polar and create a test product

Polar provides an official connection with browser sign-in, so you don’t need to paste an API key into chat. Its MCP setup guide lists the supported clients and tools.

1. In an AI client that supports remote MCP, add a connection named polar-sandbox using https://mcp.polar.sh/mcp/polar-sandbox.
2. Complete the browser sign-in for your sandbox organization.
3. Ask the agent to identify the organization and environment and list the available product, benefit and checkout-link tools before changing anything.

Connector availability depends on your AI app and workspace. OpenAI’s connection guide explains the desktop, Codex and web options; web plugins and local MCP configuration are different routes.

Polar’s published tool list includes creating products, benefits and checkout links, and attaching benefits to products. A “benefit” is what the buyer gets, such as access to your ZIP. The list does not currently include creating or uploading files. Upload your ZIP in the dashboard, then let the agent attach its file benefit. Polar file downloads.

For a fully automated upload, a coding agent with access to the local ZIP can use Polar’s Files API and upload-completion endpoint. That needs a separate API connection. Keep the scoped token in a local secret store or environment variable outside Git and browser code. A token grants account access; putting a ZIP in a chat doesn’t automatically make it available to the upload tool.

Connect Stripe, or prepare Lemon Squeezy

Stripe’s official MCP server is at https://mcp.stripe.com. Follow its setup instructions for your AI app, sign in, and verify the connected account is a sandbox. Ask the agent to create the product, its EUR price and a Payment Link. A hosted link is enough for your website’s buy button.

You still need a delivery system. Follow Stripe’s fulfilment guide to check payment on the server before granting file access and to avoid delivering twice when an event repeats. A visit to the success page alone isn’t proof of payment.

For Lemon Squeezy, let AI prepare the listing, then create the product and upload its files in the dashboard. Its public Products API documents reading products, not creating them. The Checkout API can create a checkout for an existing variant. Having an API key doesn’t remove the initial dashboard step.

A prompt for the connected agent

Replace the example details and give this to your agent after connecting the test account. This is a suggested workflow, not a claim that every AI client can complete every step.

Set up my Weekly Planning Workbook as a one-time €19 EUR product in the connected sandbox. The delivery file is weekly-planning-v1.zip and support is hello@example.com. First identify the account, environment and available tools. Show me the proposed listing, tax display and file setup before creating anything. Check for an existing matching product so a retry won’t create duplicates. After I approve, create the supported parts, connect the real file benefit or delivery method, and return the product ID and reusable checkout link. List anything I must finish manually. Keep live products, customer records and emails unchanged. Don’t call delivery tested until we’ve opened the buyer’s download.

Buy it once in test mode

Start on your product page and use the provider’s test payment details with an address you control. Follow the receipt or customer-access link, download the file and open it. Check the name, currency, total and contents. Also try cancelling checkout: it must not create a new paid order or grant new file access.

Keep a small record of the product ID, checkout link and file version. Use a permanent link for the buy button, such as a Polar Checkout Link, rather than copying a temporary payment session from the address bar.

Once the account is approved and the test works, set up and check the live version separately. Polar has a distinct sandbox environment and a live MCP endpoint, https://mcp.polar.sh/mcp/polar-mcp. A working sandbox link still takes test payments. Check the live destination before publishing your buy button.