Penetration Testing Cost for UK Fintechs and Payment Firms (2026)

A penetration test for a UK fintech typically costs £9,900 to £50,400 in the UK market. The low end is one onboarding flow and its API. The high end is a bank-partner pack covering the web platform, the APIs, the mobile app and the perimeter. The price is the number of testing days multiplied by a day rate of £1,100 to £1,400.

What does a penetration test cost for a fintech?

Most fintechs fall into one of four scopes, typically costing between £9,900 and £50,400 in the UK market. What you pay depends on how many payment and customer-facing systems are tested and how many of them move money, because that sets the number of testing days. The table shows the typical range for each scope.

Scope	What is tested	Days	Typical UK cost
Onboarding and KYC flow	A single-role onboarding web journey with identity checks, and the REST API behind it	9 to 10 days	£9,900 to £14,000
Wallet app and backend	The iOS and Android wallet, with biometric and payment features, and the API it talks to	14 to 19 days	£15,400 to £26,600
Merchant dashboard and payment API	A multi-role merchant dashboard, payouts, webhooks and a regulated payment API with many endpoints	18 to 27 days	£19,800 to £37,800
Bank-partner pack	Web platform, APIs, mobile app and the internet-facing perimeter in one engagement	25 to 36 days	£27,500 to £50,400

These are market ranges, worked out from typical engagement lengths and UK day rates of £1,100 to £1,400. They are a guide for budgeting. The pricing page shows the engagement lengths for each type of test, and the quote form gives an exact fixed price for your scope.

What drives the price?

The number of testing days drives the price, and the scope drives the number of days. A fintech is usually a small product with a large API surface, so the day count follows endpoints, money movement and tenants. Five things move it.

• Endpoints. A single REST API with fewer than 25 endpoints is a short test. A payment API with hundreds of endpoints and OAuth flows is several times longer. See API penetration testing.
• Money movement. Balance consistency under race conditions, payout redirection and refund logic each need their own tests, so a platform that moves money takes longer than one that only reads data.
• Tenants and roles. A merchant dashboard has to keep one merchant’s data away from another’s. Every role and tenant boundary adds time.
• Webhooks and environments. Webhook authenticity, and the boundary between sandbox and production, are tested as part of the payment scope.
• Mobile. A wallet app adds device-side checks for pinning, storage and biometrics on top of the API test. See mobile application penetration testing.

Tester grade is not a pricing factor, and neither is the size of the fintech or of the testing company. Two quotes for the same scope should differ mainly in the number of days. If one quote is much lower, compare the day counts first.

What is included, and what costs extra?

A quote should cover scoping, testing, the report, a walkthrough of the findings and a retest. Ask every company you approach to confirm each of those in writing, because retests and out of hours work are the two items that most often appear later as extra charges.

With EJN Labs, the quote is a fixed price for a defined scope. It includes:

• Testing by UK-based, CREST-certified testers.
• Findings in a client portal as they are confirmed, each with a CVSS score.
• The report on the last day of testing, and a walkthrough call.
• Free retests until findings are resolved.
• Out of hours slots, with no out-of-hours, callout, cancellation or rescheduling fees.

What changes the price is a change of scope: a new product line added after the quote, a second payment API, or a mobile app that was not in the original list. A release that ships mid-engagement is a common cause, so tell the testing company your release dates up front. If the scope grows, you get a new fixed price before any extra work starts.

How do you get a quote, and what will you be asked?

Send the list of systems you want tested and say who has asked for the evidence. For a fintech that is often a bank partner, a sponsor bank or an enterprise client, so say which. A testing company needs a few facts about each system to count the days.

1. Which products are in scope: onboarding, wallet, card issuing, payouts, merchant dashboard, open banking or payment APIs.
2. For each API, roughly how many endpoints, how it authenticates, and whether an OpenAPI specification is available.
3. For each web platform, the number of roles and tenants, such as merchants, operators and support staff.
4. Whether there are mobile apps, and whether they hold payment or biometric features.
5. Whether a sandbox exists, and whether testing will be on staging or on production with restricted scope.
6. Who asked for the test and the exact wording: a bank vendor review, a partner questionnaire, your own board or an investor.

Fintech organisations can use a CREST-accredited company or a CBEST provider, depending on what their requirement states. EJN Labs is CREST-accredited. If the document that triggered the request names an accreditation, say so when you ask for the quote.

Which rules shape the scope for a fintech?

Two sets of rules reach a fintech, and neither names a penetration test. The FCA’s policy statement PS21/3 on operational resilience affects entities authorised or registered under the Payment Services Regulations 2017 or the Electronic Money Regulations 2011. If a bank is your customer, the PRA’s SS2/21 sets out how PRA-regulated firms should manage outsourcing and third party risk, which is why bank vendor reviews ask suppliers for evidence.

Our guide to where penetration testing sits in PRA SS2/21 vendor reviews goes through the questions a bank is likely to ask.

How EJN Labs approaches pricing for fintechs

EJN Labs is a CREST-accredited UK penetration testing company with a dedicated fintech penetration testing service. We scope each system by what it does and who uses it, count the days, and give you one fixed price for the defined scope.

We test payment and open banking APIs, merchant dashboards, wallets, card issuing, payment orchestration and KYC onboarding, including Strong Customer Authentication flows, balance consistency under race conditions, payout redirection, merchant isolation, webhook authenticity and the boundary between sandbox and production.

Testing is safe by default on production, with no denial of service. Retests are free until findings are resolved, so the price you agree covers the evidence that issues were fixed as well as the evidence that they were found.

Frequently Asked Questions

How much does a penetration test cost for a fintech?

Typically £9,900 to £50,400 in the UK market. An onboarding flow and its API at 9 to 10 days is £9,900 to £14,000. A wallet app and backend at 14 to 19 days is £15,400 to £26,600. A bank-partner pack of 25 to 36 days is £27,500 to £50,400. These ranges use UK day rates of £1,100 to £1,400.

Why do payment APIs cost more than other APIs?

Because they usually have more endpoints and more ways to go wrong. Payment APIs need tests for authorisation between merchants, race conditions on balances and payout changes, as well as the standard API checks. A regulated payment API with many endpoints is typically 10 to 15 days on its own.

Is a retest included in the price?

It depends on the company, so ask for it in writing. With EJN Labs, retests are free until findings are resolved, and there are no out-of-hours, callout, cancellation or rescheduling fees. The quote is a fixed price for a defined scope.

Can a fintech test the sandbox instead of production?

Often, yes, but say so when you ask for the quote. A sandbox test is useful, though the boundary between sandbox and production is itself part of the scope. EJN Labs is safe by default on production, with no denial of service, so a restricted production test can sit alongside the sandbox work.

How long does a penetration test take for a fintech?

Between 9 and 36 testing days for the scopes in the table above. An onboarding flow and its API is typically 9 to 10 days, a wallet app and backend is 14 to 19 days, and a bank-partner pack is 25 to 36 days. EJN Labs delivers the report on the last day of testing.

Get a fixed price for your product

Tell us which products are in scope and who has asked for the evidence. Request a fixed-price quote and we will come back with the number of days, the price and the earliest start date.

Related: Best Penetration Testing Companies for UK Fintech, fintech penetration testing, penetration testing cost in the UK, API penetration testing and penetration testing in PRA SS2/21 vendor reviews.