Checkout.com is an enterprise card processor, and it’s the one gateway here you can build against before you’re a customer: a free sandbox account gets you working test payments, and you only talk to their sales team when you’re ready to take real money.
That order of events shapes this guide: you’ll set up with sandbox keys, test properly, then swap in live keys.
What connecting Checkout.com gives you
Card payments. Like NMI, Checkout.com doesn’t unlock additional local payment methods in Funnelish: no Klarna, no iDEAL. Connect a second gateway if you need those.
It does give you direct control over 3D Secure, which most gateways here don’t expose. More on that below.
Before you start
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A payment form element is on your checkout step, with Funnelish Pay switched on. See Add payment methods to your checkout.
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A
Checkout.comaccount: either a free sandbox account to start with, or a live merchant account if you already have one.
Get your API keys
You need two, created separately. Have a scratch file open to paste them into as you go, because you can’t read either one back out of Checkout.com afterwards.
Public API Key
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Log in to your
Checkout.comaccount. -
In the side menu, click Developers → Keys.
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Click Create a new key.
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Select Public API Key.
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Add a key description if you want one. It’s optional, but
Funnelishwill save you guessing later. -
Scroll to Select processing channels and check the box. This one is required.
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Click Create key.
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Copy the key, paste it into your scratch file, then click Close.
Copy the Key, not the Key ID. They sit next to each other and look similar. Pasting a Key ID gives you a gateway that saves cleanly and then fails at checkout, with nothing to indicate why. This is the single most common
Checkout.comsetup mistake.
Secret API Key
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Click Create a new key again.
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Select Secret API Key.
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Add a description if you want one.
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Under Scopes, choose Default or Select all. Nearly all the scopes are needed for the gateway to work properly, so don’t trim this down.
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Scroll to Select processing channels and check the box. Required again.
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Click Create key.
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Copy the key into your scratch file and click Close.
Same warning applies: the actual Secret API Key, not the Key ID.
Sandbox keys contain the word
test.Checkout.com’s sandbox keys look likepk_test_...andsk_test_..., while live keys don’t. That’s the quickest way to check which environment a gateway is pointing at, later on when you can’t remember.
Connect Checkout.com
You can start this from either Account → Payments → Gateways or the page builder. These steps use the builder, so you can see the result on the form as you go.
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Open your checkout step and click the payment form element.
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In the settings panel, click Edit payment options.
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Click Connect a new gateway, then choose Credit Card.
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Pick
Checkout.com. -
Give the gateway a name. It’s internal only, so name it for what it points at:
Checkout.com — sandboxandCheckout.com — livewill save you real confusion later. -
Paste in your Public Key and Secret Key.
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Set your 3DS options. See below.
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Create the gateway, then select it on the payment form and save your changes.
3D Secure options
Checkout.com lets you decide how card authentication behaves, which is a genuine lever on your conversion rate, and a genuine lever on who absorbs fraud losses.
Enable 3DS: every payment goes through 3D Secure authentication before processing. Your customer may be asked for a code from their bank.
Attempt non-3DS when possible: toggled alongside 3DS, this skips authentication wherever the rules allow it, reducing friction at checkout.
How to choose:
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Selling into the UK or EEA? Keep 3DS on. Strong Customer Authentication is a regulatory requirement there, and payments without it get declined by the issuer rather than approved.
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Weighing friction against fraud? Authenticated payments generally shift liability for fraudulent chargebacks to the card issuer. Skipping authentication keeps checkout smoother and leaves that liability with you. If you sell a high-chargeback product, that trade is worth thinking about properly.
If you’re unsure, start with 3DS on. A slightly longer checkout is easier to recover from than a run of chargebacks.
Testing your Checkout.com setup
Sandbox keys are the whole point of setting up this way. Create your gateway with them, then turn on Test Mode with the toggle in the funnel’s top bar and run a purchase through your own checkout.
Run a sandbox payment
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Open the funnel step with the payment form and visit its URL.
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Add a product to the cart and select the
Checkout.compayment option. -
Enter any billing details.
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Use this card:
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Number:
4242 4242 4242 4242 -
Expiry: any future date
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CVC: any three digits
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Complete the purchase.
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In your
Checkout.comsandbox account, click Payments in the side menu. Your test order should be there, showing the status AUTHENTICATION REQUESTED.
If the order reaches Funnelish but never appears in Checkout.com, your keys are wrong. Almost always a Key ID pasted instead of a Key.
Test more than the happy path. Try an expired date and a failed 3DS challenge too, so you know what your customer sees when a payment doesn’t work.
Then go live
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Contact the Checkout.com sales team to move onto a live merchant account.
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Generate live API keys the same way: same two key types, same processing-channel checkbox.
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Replace the sandbox keys in your Funnelish gateway with the live ones. Or create a separate live gateway and switch the payment form to it, which is cleaner if you ever want to test again.
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Run a real purchase for $1, check it in both Funnelish and
Checkout.com, then refund yourself and set the price back. -
Turn Test Mode off. It’s the first item on the funnel launch checklist, and a funnel left in test mode looks like it’s taking orders and charges nobody.
test.
What to check beyond “the payment went through”
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The order appears in Funnelish with the correct product, amount and currency
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Any upsell or OTO step charges correctly, not just the first step
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Your confirmation email and any automations actually fired
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The checkout works on mobile, not only on desktop
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The 3DS challenge appears and completes, if you have it enabled
See Test payments before launch for the full pre-launch process.
Where your gateways live
A gateway belongs to your account, not to a funnel. You connect Checkout.com once and it’s available everywhere from then on: every funnel, existing or new, just selects it from the list.
You can see and manage every gateway on your account under Account → Payments → Gateways (app.funnelish.com/settings/payments/gateways). Worth keeping tidy here in particular, since a sandbox gateway and a live one will look almost identical in the list.
If something isn’t working
The order appears in Funnelish but not in Checkout.com. Verify both keys. A Key ID pasted in place of a Key is the usual cause, and it produces exactly this symptom.
Checkout.com is connected but the checkout shows no card fields. Check the gateway is selected and saved on the payment form, and that Funnelish Pay is switched on in the payment options.
Payments are declining for European customers. Check 3DS is enabled. Without authentication, issuers in the UK and EEA will decline rather than approve.
Live orders aren’t taking money. Check whether the gateway still holds sandbox keys (they contain test) and whether Test Mode is still on for the funnel.
Payment processing is the fiddliest part of building a funnel. Gateway credentials, currencies, country rules, the form itself: a lot of moving parts, and the one area where a mistake costs you orders rather than just looking wrong.
If your Checkout.com connection isn’t behaving, start a topic in Ask the community. Someone will help. For anything tied to your account or a specific transaction, contact us on chat support.