MAILGENT
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Drop in a checkoutthat settles in seconds.

One line of JavaScript and any site can take USDC. Mailgent handles the wallet UX, the signature, the on-chain settlement, and the receipt. Funds in the merchant wallet in about two seconds — never seven days.

Stripe Checkout took the friction out of cards. Mailgent Checkout takes the friction out of crypto. Customers see a familiar payment sheet, sign with passkey or wallet, and the merchant receives USDC before the confirmation page loads. There is no SDK to learn, no contract to deploy, no compliance review to schedule. The integration is a script tag, the payment is a fetch call, and the receipt is signed and on-chain.

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How it works

Four steps. Most fire in under a second.

01

Drop in the snippet

Add a single script tag or install the npm package. Configure your project key. The checkout button now renders anywhere you want — on a product page, in a cart, on a paywall.

02

Customer signs and pays

Customer clicks the button, sees a Mailgent payment sheet, signs with passkey (if they have a Mailgent wallet) or connects an external wallet. The signature authorizes the exact amount and merchant.

03

Mailgent settles on chain

Mailgent submits the signed transaction to Base, waits for confirmation (about two seconds), and routes the USDC to the merchant's project wallet. The merchant gas is sponsored.

04

Webhook + receipt

Mailgent fires an HMAC-signed webhook to the merchant fulfillment endpoint with the order details and a signed receipt. The buyer sees the confirmation page; the merchant ships.

What you get

Built for developers who already shipped.

One snippet, every framework

Hosted checkout via a script tag, or embedded via the SDK. Works on Next, Remix, Astro, Rails, Django, plain HTML — anything that renders a button on a page.

Two-second settlement

Customer signs, Mailgent verifies and settles to the merchant wallet on Base mainnet. The 'thanks for your order' page loads on confirmed funds, not a promise that will clear in three business days.

Fulfillment webhook

Every paid order fires an HMAC-signed webhook with idempotency keys and exponential retries. Replay UI in the console for the rare manual recovery. Idempotency means safe at-least-once delivery.

Built-in refund flow

Issue a refund through one API call or click in the console. Mailgent sends USDC back to the buyer, updates the order, fires the refund webhook. There are no chargebacks to fight because settlement is on-chain.

Signed receipts on every order

Every settled order returns an Ed25519-signed receipt linking the merchant identity, the buyer wallet, the amount, and the Base transaction hash. Hand it to your accountant or store it for the seven-year retention window.

Subscriptions + recurring

Customers grant a recurring mandate at signup (cap, frequency, expiry). The merchant charges on the schedule with a single API call; the wallet enforces the mandate on-chain. Cancel any time.

What people build

Real-world checkout flows shipping today.

1-tap

E-commerce checkout

Replace or supplement Stripe Checkout on a Shopify, Woo, or custom storefront. Buyers with Mailgent accounts skip card forms entirely.

Per-doc

Paywalled downloads

Sell a PDF, video, or dataset for a one-time USDC payment. The webhook unlocks the download URL; no subscription required.

Recurring

Membership + SaaS

Charge $9/month for a membership. The customer's mandate authorizes the cap; you call charge() on each billing cycle. No card-on-file regulation.

Tip jar

Tips + donations

A 'pay what you want' button with a minimum and a suggested amount. Common on creator sites, open-source repos, and one-off support pages.

Stripe Checkout vs Mailgent Checkout

What the difference looks like.

FeatureStripe CheckoutMailgent Checkout
Minimum charge$0.50 + 2.9% per transaction (US)$0.01 USDC, no fixed minimum
Settlement windowTwo to seven business daysAbout two seconds on Base mainnet
ChargebacksUp to 120 days, fee per disputeNone — settlement is on-chain and final
Customer KYC for merchantRequired by Stripe for every merchantTier-gated per amount; defaults to none below $100
Receipt formatStripe dashboard PDFEd25519-signed receipt + Base transaction hash
Payout to bankACH on a schedule, 1099-K reportingWithdraw USDC to any wallet; convert separately as needed

FAQ

Things builders ask.

Do my customers need a wallet?
No. If a customer signs in to Mailgent during checkout (email + password), a wallet is provisioned for them transparently. They can top up with a card, ACH, or USDC transfer. Customers with existing crypto wallets can also connect them — Mailgent Checkout speaks WalletConnect.
How do I handle inventory updates?
The fulfillment webhook fires on every settled order with an idempotency key. Verify the HMAC signature, mark the order paid in your database, decrement inventory. If the webhook is retried, the idempotency key prevents double-counting.
Can I prevent a customer from paying?
Yes. Before the customer signs, your server can call /v0/checkout/validate with the cart contents. Return an error and Mailgent blocks the signature. Useful for inventory-limited products, geofencing, and risk checks.
What about taxes?
Mailgent Checkout does not calculate tax in v1. Pass a pre-calculated tax amount to the checkout call (via line items) or integrate with your existing tax engine (TaxJar, Avalara, Stripe Tax). The receipt itemizes whatever you provided.
Are refunds free?
Gas costs to the merchant wallet (about $0.001 on Base). Mailgent does not charge a per-refund fee. The refund webhook fires, the original order updates to refunded, the activity timeline records the reversal.
Can I customize the checkout look?
Hosted checkout supports theme colors, a logo, and your domain on the receipt. The embedded SDK gives full control of the UI — render your own payment sheet and call the Mailgent signing primitive directly.
What about subscriptions?
Subscriptions ride on Mailgent mandates. The customer signs a mandate at signup (e.g., '$9/month, up to 24 months, cancel any time'). Your server calls charge() on each billing cycle; the wallet enforces the cap on-chain. Cancel through the API or console.
What is the fee?
First $100 of revenue is always free. After that, 5% on settled mainnet payments — waived for now. No card, no monthly fee, no per-seat.

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