Payment gateway integration, BNPL, callback handling, and high-risk merchant playbooks.
8 articles
AI assistants like ChatGPT can now find products and check out for shoppers. Here is how agentic commerce works and how to make your Magento or Hyvä store ready: honestly, and step by step.
Stripe, PayPal, and Adyen all terminate high-risk Magento merchants once the MCC code reads CBD, vape, or adult. The working stack is NMI, Easy Pay Direct, and eMerchantBroker, each with different rate cards, reserve requirements, and compliance hooks. Here is the real rate range, the chargeback thresholds that trigger offboarding, the Magento 2.4.4-2.4.9 module pattern that abstracts gateway switching per product category, and the compliance checklist for each vertical.
Five BNPL providers ship against Magento 2.4.4-2.4.9 in 2026: Klarna, Afterpay (Cash App Pay-in-4 in the US since 2025), Affirm, Sezzle, and PayPal Pay Later. Their region coverage, merchant fees, AOV sweet spots, and Hyvä-compatibility maturity have diverged sharply. This post lays out the per-region availability matrix, real fee ranges from each provider's merchant docs, Magento Marketplace extension maturity, and the decision tree we run on every BNPL engagement.
Most extension comparison posts age out in six months. This is an annual maintenance audit of the three biggest payment extensions for Magento (PayPal Commerce Platform, Adyen Magento Plugin, and Klarna Payments), measured across five hard axes: GitHub commit velocity in the last 90 days, Magento Marketplace average rating, open-to-closed issue ratio, real support response time, and PHP 8.4 + Magento 2.4.9 compatibility status. Each extension gets a maintainability score and a recommendation by store size segment. Updated quarterly.
Three real production failures we shipped fixes for in 2026 on Magento 2.4.4-2.4.9: a Stripe webhook retry that double-captured an order, a double-click on Place Order that ran submitQuote twice, and a webhook signature check that compared HMACs with == and leaked the secret. Each one has a small, boring fix, a UNIQUE key on (gateway, event_id), a SELECT FOR UPDATE on the quote row, and hash_equals. Here is the exact PHP, SQL, the observer wiring, and the Stripe CLI replay command to prove it works.
Razorpay ships an official Magento module, razorpay/razorpay-magento on Marketplace and GitHub, that covers Cards, NetBanking, UPI Collect, UPI Intent, Wallets, EMI, and PayLater. The defaults work; production does not. This is the install command, the system.xml API-key config, the webhook signature check for payment.captured and refund.processed, the RBI 2-factor authentication redirect, the UPI AutoPay e-mandate flow for subscriptions, and the T+1 to T+3 settlement timing every Indian merchant needs to plan around. Magento 2.4.4-2.4.9, INR-only stores.
Stripe ships stripe/module-payments, the official Magento Marketplace extension that handles Payment Element, 3DS2 SCA, webhooks, partial refunds, and Stripe Billing subscriptions out of the box. It covers 95% of stores. The other 5%, B2B with biometric-bypass 3DS2, micro-fee rounding into the customer's total, ACH/SEPA mandate caching, high-risk merchants, marketplace platforms running Stripe Connect Direct Charges with custom application_fee_amount logic, need either a fork of the official module or a full from-scratch integration. Here is the decision tree, the PaymentIntent + SetupIntent code, and a realistic cost estimate for each path.
Most custom payment method tutorials show one or two files and leave the integration broken on Hyvä, broken in admin, or broken on capture. Here is the complete minimal working extension for Magento 2.4.4-2.4.9: the 9 files you cannot avoid (module.xml, config.xml, di.xml, payment.xml, adminhtml system.xml, Model/Payment.php, Knockout renderer, .html template, checkout_index_index.xml), the Hyvä Magewire parallel, a verified webhook handler with signature checks, and the refund flow wired through onlineRefund. Copy-paste ready, tested against Magento 2.4.9, PHP 8.4, Hyvä Checkout 1.2.
