Guest Checkout
Let buyers pay without creating an account, and offer to save their details afterwards.
What it adds
A checkout path that takes an email, an address, and a payment without requiring registration, with optional account creation after the order is placed.
What your agent is told to do
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What your agent is told to do
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Ask for the smallest set of fields that completes the order: contact email, shipping address, payment. Do not ask for a password, and do not put an account creation form in front of the payment step.
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Create the order record before you attempt payment and give it a stable reference. Every retry, decline, and successful charge attaches to that same order, so support can trace a customer's failed attempts.
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Offer account creation on the confirmation screen, after the money has moved, and pre-fill it from what was already entered. If the app has Email Verification, use it to claim the order rather than inventing a second confirmation flow.
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Validate the shipping address and the deliverability of the destination before the payment step, so the buyer fixes a typo before a charge is attempted rather than after one is declined.
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Do not sign the guest in or create a shadow account silently. A hidden account with an unset password becomes a support problem the first time that person tries to register properly.
Edge cases it handles
8
Edge cases it handles
8- A double-click on pay, or a refresh mid-payment, must not produce two charges. Generate an idempotency key per checkout attempt, disable the control once submitted, and make the server reject a repeat of the same attempt.
- A browser crash or an expired session must not lose a half-finished checkout. Persist the entered details against the order reference so returning to the checkout link restores the form where it was left.
- If the entered email already belongs to an account, say so and offer sign-in, but do not block the purchase and do not confirm or deny the account's existence in a way that lets someone probe your customer list.
- Address validation runs before payment. A failed delivery check after a successful charge means a refund and an unhappy buyer, so surface the problem while it is still free to fix.
- The order reference must stay stable across payment retries and declines. Issuing a new number on every attempt makes reconciliation and customer support impossible.
- A guest order still needs a way to be looked at later. Send a link that authorises viewing that one order and nothing else, and expire it.
- Payment succeeding while the confirmation response is lost is normal. Reconcile from the payment provider's record rather than assuming an unreturned request means no charge.
- Card details must never touch the app's own storage or logs, even in an error path that dumps the submitted parameters.
Definition of done
8
Definition of done
8- A buyer completes a purchase end to end without creating an account or setting a password.
- Double-submitting or refreshing during payment produces exactly one charge.
- An interrupted checkout can be resumed with the entered details intact.
- The order reference is unchanged across declines and retries.
- An email matching an existing account offers sign-in without leaking whether the account exists.
- Account creation is offered after the order and reuses the details already entered.
- The feature matches the existing design system.
- No existing functionality is broken.
Related features
Usage Limits
Usage Limits
Cap what free accounts can do — visibly and fairly.
What it does
Per-plan usage limits, enforced server-side, with the user always able to see where they stand.
How it works
- 1 Define limits per plan in one place. Do not scatter magic numbers through the codebase.
- 2 Enforce on the server at the point of creation. A client-side check is decoration.
- 3 Show current usage BEFORE the user hits the wall — surprise limits feel like a bug.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/usage-limits
Upgrade Modal
Upgrade Modal
Sell the upgrade at the exact moment someone wants it.
What it does
A focused upsell that appears when a free user reaches for a paid capability.
How it works
- 1 Trigger it at the point of intent — when they click the locked thing — not on a timer or on page load.
- 2 Name the specific feature they just tried to use. A generic pricing modal converts far worse.
- 3 State the price plainly and give one button to upgrade.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/upgrade-modal
Billing Portal
Billing Portal
Let people manage their own subscription.
What it does
A billing area where users can see their plan, change payment method, get invoices, and cancel.
How it works
- 1 Use the payment provider's hosted billing portal if it has one. Do not rebuild card management — it's a PCI liability you don't need.
- 2 Show the current plan, renewal date, and payment method on your own account page.
- 3 Make cancelling possible without emailing support. Dark patterns here generate chargebacks.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/billing-portal
How it works
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1
Copy the link
Grab the Markdown instruction URL for this feature.
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2
Give it to your AI
Paste it into Claude Code, Cursor, v0, Lovable — whatever you build with.
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3
It inspects, then implements
Your agent reads your existing app first, then adds the feature to fit it.
Works with your stack
These instructions are written to adapt. They tell the agent to detect your framework, match your existing design system, and reuse what you already have — rather than assuming a particular stack.
Need it tighter than that? Customize the feature and tell it exactly what you're running.