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What is Strong Customer Authentication? SCA and 3-D Secure explained

By SendPay Business · · 2 min read

A quick ID check
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Strong Customer Authentication, or SCA, is a rule in the UK and Europe that makes people prove it's really them before many online payments and account logins. It came from the EU's second Payment Services Directive (PSD2) and has cut card fraud online.

The two-of-three rule

SCA needs two separate checks from different groups:

  • Something you know, like a password or PIN.
  • Something you have, like your phone or card.
  • Something you are, like a fingerprint or face scan.
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How it works for card payments

Online card payments usually meet SCA through 3-D Secure, the step where the customer's bank asks them to approve the payment in their banking app or with a code. Branded as Visa Secure or Mastercard Identity Check, it's run by the card issuer, not the shop.

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When it isn't needed

There are exemptions, such as some low-value payments, repeat payments to a business the customer has trusted, and subscriptions after the first payment. Whether one applies is decided by the customer's bank, so businesses should always be ready for the check.

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What it means for money apps

Any app that holds customer money or issues cards has to build SCA into its logins, payments and card spending. Choosing a platform and partners that handle it for you saves months of work.

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How it works

Your own money app
  1. Name it and pick your colours
  2. Choose what it does
  3. Launch when you are ready

Why sign up

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It's all about creating your own financial platform with ease. Start with a free account today.

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  • Get paid from day oneTake card payments, and share your own payment link and invoices so customers pay in a click.
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SendPay Business is a technology company, not a bank. Accounts, cards and payments are powered by licensed partners.

Questions people ask

What is my card approval rate?

Work out your authorisation rate and what declines cost you.

Authorisation rate calculator →
Why do apps check my identity when I sign up?

That's KYC, a separate rule from SCA. The guide explains it.

What is KYC and AML? →
What is a chargeback?

When a cardholder's bank reverses a payment. SCA helps prevent fraud-related ones.

What is a chargeback? →
What is open banking?

A secure way for apps to connect to bank accounts, also covered by PSD2.

What is open banking? →

Read next

Spotted a mistake or something out of date? and we'll fix it. How our guides are made

This guide is general information, not legal or financial advice. SendPay Business is a technology company, not a bank, and does not take deposits; regulated services on the platforms are provided by licensed partners. Other companies named in this guide are reference points only and are not affiliated with SendPay Business.