Buy now, pay later has moved from a niche workaround to a mainstream checkout option at tens of thousands of US retailers. Walk through an online checkout at a major clothing brand, a furniture store, or a travel booking site, and you'll almost certainly see at least one of three names: Klarna, Affirm, or Afterpay. All three let you split a purchase into installments. All three are free if you pay on time. But they differ meaningfully in how they structure payments, what they cost when something goes wrong, how they handle credit, and what the app experience feels like when you're not actively checking out. The choice between them matters more than most shoppers realize.
At a glance
- Klarna — founded Sweden 2005, US app 2018; 118 million active consumers globally; 966,000 merchants; $127.9 billion in GMV (FY2025); Pay in 4, Pay in 30, and longer-term financing; 55 million+ monthly active app users globally; 3.4 million transactions per day.
- Affirm — founded San Francisco 2012; 23 million active consumers as of June 2025 (up 24% year over year); 376,800+ active merchants; $36.7 billion in FY2025 GMV; Pay in 4 and monthly installment plans from 3 to 60 months; Affirm Card; no late fees on pay-over-time products.
- Afterpay — founded Melbourne, Australia 2014; acquired by Block Inc. in 2022; 24 million+ active customers; 348,000+ global merchants; $8.24 billion in Q3 2024 gross payments volume (up 23% year over year); Pay in 4 over six weeks; in-store payments via Afterpay Card through Apple Pay or Google Pay.
Setup & onboarding
All three BNPL services share a similar onboarding baseline: download the app, provide an email address and phone number for verification, and link a debit or credit card. None runs a hard credit check for the standard Pay in 4 product — they use soft checks or proprietary approval models that evaluate each purchase individually rather than establishing a fixed credit line upfront. This makes the initial onboarding fast (typically under two minutes per app) and accessible to a broad range of consumers, including those with limited or no traditional credit history.
Where the apps diverge is in scope and tone on first launch. Klarna opens to a full shopping interface: a curated feed of brands and deals, cashback offers, price comparison tools, delivery tracking, and loyalty card storage alongside the BNPL checkout function. It's closer to a shopping super-app than a payment tool, and the breadth is immediately apparent. Affirm is more focused and visually clean: a home screen that shows your active plans, a marketplace of merchants, and a card management view. There's less surface area, which many users find easier to navigate. Afterpay falls in between: the merchant discovery directory is prominently featured, and the design is friendly and accessible, but the app doesn't try to be a full shopping platform the way Klarna does.
For users who want to get to payment approval quickly without browsing a shopping app, Affirm and Afterpay are faster to navigate. For users who want their BNPL tool to also help them discover where to use it and track what they've ordered, Klarna's breadth is the better fit.
Speed & checkout experience
At a merchant that has natively integrated a BNPL provider into its checkout flow, the experience for all three services is similar: you select the payment option, confirm your details, and a quick approval screen appears before you're returned to the merchant's order confirmation. The process adds one or two steps compared to paying with a card directly, which is a modest friction increase for the benefit of splitting the cost over time.
The variation comes at merchants that haven't integrated BNPL natively. Klarna offers a one-time virtual card that functions anywhere Visa is accepted, which gives it the widest practical reach of the three — you can technically use Klarna at any online store, not just those with a Klarna integration. Afterpay's Afterpay Card (loaded into Apple Pay or Google Pay) provides in-store contactless payment at any NFC terminal. Affirm's virtual card and the Affirm Card provide similar offline flexibility for cardholders. In-store BNPL has become a meaningful competitive dimension as the services expand beyond online-only use cases.
Security & privacy
All three services encrypt stored credentials with industry-standard protocols and comply with applicable US consumer financial regulations. In a native merchant integration, none of them transmits your raw card number to the merchant — the transaction routes through the BNPL provider's own payment rails, and the merchant receives an order confirmation, not your financial data. This is the same tokenization model used by Apple Pay and Google Pay for traditional card transactions.
Klarna and Affirm have both faced regulatory scrutiny over how clearly they disclose costs and repayment terms in some contexts. Both have improved transparency under pressure from consumer finance regulators — Affirm in particular has received attention for its per-purchase approval model and its decision to report some loan types to Experian. Afterpay's simpler product structure (always Pay in 4, no interest, fixed fee for missed payments) has generally attracted fewer compliance concerns because the cost structure is easy to communicate clearly. Our Buy Now, Pay Later guide covers the regulatory landscape for all three services in more depth, including what CFPB oversight means for your rights as a BNPL user.
Costs & fees
Klarna — Pay in 4 is interest-free if all four payments are made on time. Pay in 30 (the full balance due in 30 days, interest-free) is a useful option for purchases you'll pay off in a month. Longer-term financing plans through Klarna carry variable APR. Late fees can apply if a Pay in 4 payment is missed. Some Klarna features — the Klarna Card, certain subscription tiers, or premium one-time card features — may involve additional fees depending on the specific product and market.
Affirm — No late fees on pay-over-time plans. This is Affirm's most distinctive policy. APR on pay-over-time plans ranges from 0% to 36% depending on the specific plan, the merchant (some offer 0% financing as a promotional feature), and the applicant's creditworthiness. Pay in 4 is offered at 0% APR for qualifying purchases. If you miss an Affirm payment, there's no penalty fee — but the missed payment will affect your ability to get approved for future Affirm purchases and may be reported to Experian.
Afterpay — Pay in 4 is always interest-free. Late fees apply if a payment is missed: $8 per missed payment or 25% of the order value, whichever is lower. Total late fees per order are capped. There is no interest charged on the standard product. The fee structure is simple and predictable — most users find it easy to understand exactly what they owe and when.
Where each one wins
Klarna wins on: breadth of built-in shopping utility beyond BNPL (price comparison, cashback, delivery tracking, loyalty cards all in one app), widest geographic reach, and the one-time Visa card for use at any merchant regardless of native integration. Best choice for shoppers who want a unified shopping and payment app, or who shop across many retailers including some that don't natively support other BNPL providers.
Affirm wins on: the transparent no-late-fee policy on pay-over-time plans, the longest available repayment terms (up to 60 months) for large purchases like furniture, electronics, or travel, and clear total-cost disclosure at checkout before you commit. Best for shoppers making larger planned purchases who need monthly installments and want to eliminate any possibility of a surprise late charge.
Afterpay wins on: simplicity — one product (Pay in 4), always interest-free, always six weeks. The app is focused, approval is fast, and the fee structure is easy to internalize. Best for shoppers who want predictable installment payments without navigating a product menu or thinking about which plan is right for their situation.
Individual product detail is in our Klarna review, Affirm review, and Afterpay review. Our ranked list is available at best BNPL apps for US shoppers.
Bottom line
No single service is the right answer for every shopper or every purchase. The most useful shortcut: use Affirm when the purchase is large and you need monthly installments over several months with no late-fee risk; use Afterpay when you want simple Pay in 4 at a retailer that supports it and you'll pay it off in six weeks; use Klarna when you want broader shopping utility — cashback, price comparison, and one-time card reach — alongside BNPL. All three are free to use if you pay on time, and all three have reached enough merchant adoption that you'll encounter them at most major US retailers.
The differentiators that matter most in practice are: whether you need monthly terms beyond six weeks (use Affirm), whether you want no late fees regardless of what happens (use Affirm), whether you want the widest reach at non-integrated merchants (use Klarna's one-time card), or whether you want the cleanest and simplest experience with one predictable structure (use Afterpay). The full side-by-side rankings are in our Best BNPL Apps 2026 comparison.