Assessment
Fourthline verifies customers when they sign up and then keeps watching them. It checks identity documents and selfies, proves addresses, screens names against sanctions and PEP lists, signs contracts with qualified electronic signatures and runs periodic re-checks, all through one API. Use it when a regulated firm in Europe wants one provider for the whole customer lifecycle in place of several point tools.
Fourthline was founded in Amsterdam, Netherlands, in 2017 and says it reached profitable scale before Paul Stoddart replaced co-founder Krik Gunning as chief executive in March 2026. Its clients include Revolut, N26, Trade Republic, Qonto, Rabobank and Triodos Bank. It raised ~$54M in 2023 in a round led by Finch Capital.
It fits a regulated bank, neobank or broker that onboards large numbers of European customers and wants checks that hold up with supervisors. It is a weaker fit for a small business that wants self-serve sign-up and a published price per check.
Rating by criterion
Each of the eight criteria below is scored out of 100.
Sector criteria
Fourthline covers document and selfie checks, proof of address, qualified electronic signatures, client authentication and re-KYC, with a focus on European documents and rules. Ask about coverage for documents from outside Europe if many customers come from further afield.
Its in-house AI checks documents and faces for forgery and fraud, and sanctions screening and transaction monitoring run alongside onboarding. Ask for false-positive and pass rates measured on customers like yours.
A case review portal lets compliance teams work flagged customers and investigations. Firms with their own case tools can take results through the API instead.
Fourthline builds for European AML rules, including the new Anti-Money Laundering Regulation, and is certified to ISO 27001. Its clients are supervised banks and brokers, which is a good sign that the checks pass regulatory review.
Vendor criteria
The product covers most of the lifecycle from onboarding to offboarding. The new chief executive plans to expand into new countries and industries, so check that your market is a priority.
Onboarding is sales-led, with a single API integration. Plan for a technical project and a compliance review of the check flows before launch.
Fourthline does not publish prices. Expect volume-based pricing and ask for the cost per check, monitoring fees and any minimums in writing.
Contracts are negotiated with regulated firms. Ask about data retention, where data is stored and how customer records move if you leave.
Against its peers
These are the other companies in KYC, AML and identity, with their ratings.
Fact file
| Clients | Revolut, N26, Trade Republic, FlatexDeGiro, Qonto, Rabobank, NN and Triodos Bank |
|---|---|
| Certification | ISO 27001 |
| Funding round, 2023 | ~$54M led by Finch Capital |
| Profitability | Profitable, according to Fourthline |
| Pricing | Not published |
Competitive landscape
Identity verification and AML providers a European bank or fintech would compare with Fourthline.
Fourthline: 75
- Fourthline75
- Sumsub84
- Persona81
- Veriff80
- Ondato76
- IDnowNot reviewed
Key leadership
Paul Stoddart became chief executive in March 2026; he earlier ran VocaLink and was president of GoCardless. Co-founder Krik Gunning, who led Fourthline from its start, stayed on as an adviser.
How this review was created
This profile gives our own assessment of Fourthline to companies selecting a KYC, AML & identity provider. The Fintech Index receives nothing for featuring a firm, for sponsorship, or for advertising, and Fourthline gave us no payment for the profile.
The rating equals the average of eight criteria, with every criterion running from 0 to 100. Four address buyer needs in this sector, and four address the company together with its commercial terms.
Ratings are our editorial judgment, made from public information: pricing and legal pages, product documentation, compliance disclosures, and filings. Fact-checking took place on October 23, 2026.