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E-Commerce · head to head

Klarna vs OpenCart

Klarna logo

Klarna

E-Commerce

Buy now pay later and instalment checkout for online and in-store merchants

From
On request
Rated
-
Full reviewWebsite
OpenCart logo

OpenCart

E-Commerce

Self-hosted open source shopping cart written in PHP, released under the MIT licence

From
Free
Rated
-
Full reviewWebsite

The short version

  • Only OpenCart has a free tier, so it costs nothing to try first.
  • Each has a real cost: Klarna merchant fees for the short-term products run around 5.99% plus a fixed fee in the United States, roughly double a standard card rate, so unless Klarna measurably lifts average order value or conversion it is a straight margin loss.; OpenCart extensions modify core behaviour through an XML patching system, so two modules that patch the same file conflict in ways that surface as broken checkout rather than as an installation error, and resolving that requires a developer reading both patches.
  • They diverge on capability: Klarna covers Pay in 4, OpenCart covers MIT licensed source.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Klarna and OpenCart actually diverge.

Attributes where Klarna and OpenCart differ
AttributeKlarnaOpenCart
Starting priceOn requestFree
Pricing modelquoteopen-source
Free tierNoYes
PlatformsWeb, iOS, AndroidWeb
FoundedUnknown2009

Identical on both: user rating (Not yet rated), category (E-Commerce).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Klarna

  • Pay in 4
  • Pay in 30 days
  • Longer-term financing
  • Klarna app placement
  • Klarna Checkout
  • In-store payments
  • On-site messaging
  • Merchant portal

Only in OpenCart

  • MIT licensed source
  • Self-hosted PHP and MySQL
  • No transaction fees
  • Multi-store
  • Extension marketplace
  • Multi-currency and multi-language
  • OCMod modification system
  • Full data access

What people use each for

The jobs each tool is most often brought in to do.

Klarna

  • A fashion or furniture retailer with average order values high enough that a 3% fee uplift is repaid by a larger basketnot OpenCart
  • A merchant selling to younger shoppers who have low credit card penetration and would otherwise abandon at checkoutnot OpenCart
  • A European retailer wanting a single hosted checkout that handles instalments, invoice and card in one flownot OpenCart
  • A brand that wants distribution inside Klarna's shopping app as an acquisition channel rather than only a payment optionnot OpenCart

OpenCart

  • A merchant with volume high enough that a percentage transaction fee costs more than a developernot Klarna
  • An agency building client stores where the client must own the code and the data outrightnot Klarna
  • A store with unusual catalogue or pricing logic that a hosted platform will not permitnot Klarna
  • Selling in a market where the local payment gateway is not supported by the mainstream SaaS platformsnot Klarna

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Klarna

  • Merchant fees for the short-term products run around 5.99% plus a fixed fee in the United States, roughly double a standard card rate, so unless Klarna measurably lifts average order value or conversion it is a straight margin loss.
  • Rates are negotiated and unpublished, which means small merchants pay the standard rate while large ones negotiate down, and you cannot benchmark what you are being charged without going to market.
  • Returns and partial refunds are handled through Klarna's systems rather than your payment processor, so your finance team reconciles a second settlement flow and customer service handles a second dispute process.
  • Buy now pay later is being brought under consumer credit regulation in the UK, the EU and Australia, which is already changing affordability checks and disclosures; the checkout experience that converts today may be legally required to add friction.
  • Klarna owns the post-purchase relationship, sending payment reminders and marketing in its own name, so a shopper who has a poor collections experience associates it with your brand while you have no control over the messaging.

OpenCart

  • Extensions modify core behaviour through an XML patching system, so two modules that patch the same file conflict in ways that surface as broken checkout rather than as an installation error, and resolving that requires a developer reading both patches.
  • Major version upgrades have broken third party extension compatibility, so moving between them means re-purchasing or re-commissioning modules and effectively rebuilding parts of the store rather than clicking update.
  • Hosting, patching, backups and PCI scope are all your responsibility, so a security update you postpone is a breach you own, and there is no vendor obligation to notify or protect you.
  • Extension quality on the marketplace is uneven and modules are sold as one-off purchases with no guaranteed maintenance, so a module central to your store can simply stop being updated and leave you holding the code.
  • The core project is maintained by a very small team relative to the platforms it competes with, so security fixes, compatibility with new PHP versions and feature work all arrive at a pace you cannot influence or pay to accelerate.

Pricing, plan by plan

Klarna

On request
  • Klarna for Business$undefined/year
    • Per-transaction percentage plus a fixed fee, negotiated by merchant
    • No published rate card; rates vary by market, product and volume
    • Short-term products priced materially above card interchange

OpenCart

Free
  • Open SourceFree
    • Core ecommerce features
    • Free support
    • Extensions available

Which should you pick?

Choose Klarna if

  • You need pay in 4.
  • You work on Web, iOS, Android.
  • You also want pay in 30 days.
Klarna review

Choose OpenCart if

  • You need mit licensed source.
  • You want to start without paying.
  • You also want self-hosted php and mysql.
OpenCart review

Questions people ask

Is Klarna or OpenCart better?
Neither clearly leads. Klarna starts at On request and OpenCart at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Klarna or OpenCart?
OpenCart has a free tier; the other does not. Paid plans start at On request for Klarna and Free for OpenCart.
Does Klarna or OpenCart run on more platforms?
Klarna runs on Web, iOS, Android. OpenCart runs on Web.
Can I use OpenCart for free?
Yes. OpenCart has a free tier, so you can try it without paying. Klarna starts at On request.
What is Klarna best used for?
Klarna is most often used for a fashion or furniture retailer with average order values high enough that a 3% fee uplift is repaid by a larger basket, a merchant selling to younger shoppers who have low credit card penetration and would otherwise abandon at checkout, a european retailer wanting a single hosted checkout that handles instalments, invoice and card in one flow, a brand that wants distribution inside klarna's shopping app as an acquisition channel rather than only a payment option. Of those, a fashion or furniture retailer with average order values high enough that a 3% fee uplift is repaid by a larger basket and a merchant selling to younger shoppers who have low credit card penetration and would otherwise abandon at checkout are not what OpenCart is typically brought in for.
What can Klarna do that OpenCart cannot?
Klarna covers Pay in 4, Pay in 30 days, Longer-term financing, Klarna app placement. OpenCart covers MIT licensed source, Self-hosted PHP and MySQL, No transaction fees, Multi-store.

Answered from the vendors’ own pages

Klarna: What does Klarna cost a merchant?

Klarna does not publish a rate card. In the United States most merchants pay around 5.99% plus $0.30 for short-term products, with longer-term financing nearer 3.29% plus $0.30, and large merchants negotiate lower.

OpenCart: Is OpenCart really free?

The software is MIT licensed with no paid edition. The costs are hosting, extensions, and a developer, and for a low volume store those can exceed a SaaS subscription.

Klarna: Does the merchant carry the credit risk?

No. Klarna pays the merchant the full amount less fees and takes the risk of the shopper not paying.

OpenCart: Does it charge transaction fees?

No. There is no platform cut and no surcharge for using your own payment gateway, which is the main financial argument for self-hosting at volume.

Klarna: Can I use Klarna alongside my existing processor?

Yes. It is normally added as an additional payment method through Shopify, Adyen, Stripe or a direct integration rather than replacing your card acquirer.

OpenCart: How hard is customisation?

Theme changes are ordinary PHP templates and are approachable. Changing behaviour means the OCMod patching system, which conflicts between extensions and needs a developer.

Klarna: Is Klarna still independent?

Yes. It listed on the New York Stock Exchange in September 2025 and holds a Swedish banking licence.

OpenCart: What is the biggest hidden cost?

Upgrades. Version transitions have broken extension compatibility before, so budget for a partial rebuild rather than assuming updates are routine maintenance.

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