The Partner Blueprint : Core Banking Engines for UK & European Fintechs

Adellet Sarkis
May 10
6 min read

Every fintech stack has a centre of gravity. For embedded banking players it's the licence. For card programmes it's the processor. But for any institution that holds accounts, moves money, and needs to know, at any given moment, exactly where every penny sits, the centre of gravity is the core banking system.

It's not glamorous infrastructure. It rarely makes headlines. But it is the reason your product either scales cleanly or falls apart under pressure.

The UK and European market now has a genuinely compelling set of options for fintechs choosing a core — from London-built cloud-native platforms trusted by global Tier 1 banks, to lean modular engines purpose-built for fast-moving digital challengers. Around 65% of banks are already in the process of moving to new-generation platforms, and the vendors competing for that opportunity have never been more capable.

This instalment maps the key providers, what they're actually good at, and how to think about the choice.

The Landscape

There is no single best core banking provider. Large banks, neobanks, PSPs, EMIs, wallets and embedded finance providers evaluate vendors by entirely different criteria — scale, deployment model, API maturity, ledger capabilities, compliance readiness, and speed to market.

The market broadly splits into two camps. Cloud-native challengers — Thought Machine, Mambu, Tuum, 10x Banking, Ohpen, Skaleet, built from scratch for API-first, real-time banking. And modernised enterprise platforms — Temenos chief among them, that have evolved their heritage systems for phased transformation at scale. Both have a place. Your position on the complexity and ambition spectrum determines which side of that line you belong on.

The Providers

Thought Machine — The Architect's Choice

London, UK | Est. 2014 - https://www.thoughtmachine.net/

Thought Machine is the UK's flagship core banking technology company. Its platform, Vault Core, is built around smart contracts, configurable logic layers that define precisely how any financial product behaves. The Product Library includes over 200 preconfigured financial products that can be rapidly deployed or customised, and new products are created using smart contracts in Vault's configuration layer, giving banks API-driven control to build any stack they want using real-time data.

Thought Machine was named a Leader in the 2025 Gartner Magic Quadrant for Retail Core Banking, with the highest position for Ability to Execute. Its investor and client list, JPMorgan Chase, Lloyds Banking Group, ING, Standard Chartered, and Intesa Sanpaolo among them, signals where it sits in the market: premium, serious, and built for institutions with real product ambition.

Setup costs are higher and reflect bespoke implementation, with longer-term payoff for institutions that need maximum configurability.

Best for: Neobanks and challenger banks with complex, bespoke product requirements. Institutions that want to own their product logic entirely.

Mambu — The Composable Platform

Amsterdam, NL | Est. 2011 - https://mambu.com/en

Mambu pioneered what the industry now calls composable banking — assembling a stack from best-of-breed components rather than committing to a single monolithic suite. Its modular, API-driven design supports customisation and rapid adaptation, making it appealing to clients with diverse and evolving requirements.

It's particularly strong in lending and consumer finance, and its marketplace of connectors makes third-party integration comparatively straightforward. Mambu's pricing model prioritises quick time-to-market and fast ROI — a meaningful advantage for fintechs under commercial pressure to move quickly.

Best for: Digital lenders, consumer fintechs, and any institution that wants composable architecture with fast deployment and a large integration ecosystem.

10x Banking — The SaaS Supercore

London, UK | Est. 2016 - https://www.10xbanking.com/

Founded by former Barclays CEO Antony Jenkins, 10x set out to rebuild core banking as a proper SaaS product. Its SuperCore platform is delivered as Software-as-a-Service, designed to simplify deployment, integration, and infrastructure operations — lowering the cost to serve without sacrificing the flexibility to configure and extend financial products.

Backed by JPMorgan Chase, BlackRock, and Nationwide, 10x has been steadily expanding its footprint and is increasingly the choice for institutions that want modern infrastructure without the operational complexity of running it themselves.

Best for: Banks and larger fintechs that want a managed, scalable SaaS core — particularly those prioritising operational efficiency alongside product flexibility.

Temenos — The Enterprise Standard

Geneva, CH | Est. 1993 - https://www.temenos.com/

Temenos is the most widely deployed core banking platform in the world, and for larger institutions undergoing transformation rather than replacement, it remains the default consideration. It covers retail and corporate banking, payments, treasury, and lending, and supports a gradual approach to core modernisation — allowing institutions to adopt new components without replacing the entire system at once.

It's not the right choice for a greenfield neobank. But for a mid-to-large institution with a complex legacy estate and regulatory obligations across multiple jurisdictions, Temenos offers something few cloud-native challengers can: proven scale, deep compliance history, and a migration path that doesn't require burning everything down.

Best for: Traditional banks, building societies, and large financial institutions undertaking phased digital transformation across complex regulatory environments.

Tuum — The European Modular Contender

Tallinn, EE | Est. 2019 - https://tuum.com/

Tuum is one of the most interesting emerging platforms in the European market. Built API-first on a microservices architecture, it enables seamless management of multiple brands, regulated entities, and regional business units within a single instance — supporting cross-border operations with tenant-specific pricing, limits, and behavioural rules.

That multi-entity capability makes it particularly compelling for BaaS-enabled fintechs and institutions expanding across Europe. A key differentiator is its support for agnostic deployment — allowing local implementation where needed, which proved critical for long-term compliance with European data localisation requirements. Backed by Citi Ventures, BlackFin Capital Partners, and CommerzVentures, it's graduating from challenger to contender.

Best for: Growing European fintechs, BaaS providers, and digital-first banks that need strong multi-entity and multi-currency capability from day one.

Ohpen — The Savings & Investments Specialist

Amsterdam, NL | Est. 2009

Ohpen doesn't try to be everything. It was the first company to bring core banking to the cloud, and has maintained a deliberate focus on savings, investment, and mortgage account administration for established financial institutions. Its API-first platform covers savings, investments, lending, and mortgages — ideal for banks transitioning specific product lines to a cloud-based model.

Clients include Nationale-Nederlanden, BNP Paribas Personal Finance, and LeasePlan Bank. If your core problem is a legacy savings or investment administration platform — not your entire banking stack — Ohpen is purpose-built for exactly that.

Best for: Established banks, wealth managers, and insurance-linked financial products needing a specialist cloud engine for savings, mortgages, or investments.

Skaleet — The Open Ecosystem Builder

Paris, FR | Est. 2015 - https://skaleet.com/en

Skaleet operates on a simple but powerful premise: the best core banking platform is one that gets out of the way and lets you integrate the best tool for every job. Institutions select specialised providers for KYC, fraud detection, payment processing, or credit scoring, and integrate them through standardised connectors. Skaleet manages the coordination, data flows, and business logic.

Its cloud-agnostic architecture serves neobanks, universal banks, and payment service providers, and it has a strong track record of fast implementation — including a Benelux corporate banking deployment completed in under 12 months, already processing hundreds of millions of euros in client transactions.

Best for: Neobanks, EMIs, and PSPs that want maximum ecosystem openness and the freedom to build a curated, composable stack without vendor lock-in.

How to Choose

Five dimensions that matter more than any feature list:

Architecture fit — Greenfield build or phased migration? Cloud-native platforms suit the former; Temenos and 10x suit the latter.
Product complexity — The more bespoke your products, the more you need genuine configurability. Vault Core's smart contracts and Tuum's modular structure are strongest here.
Speed to market — Mambu and Skaleet are built for fast deployment. Thought Machine and 10x reward the institutions that invest in a longer implementation.
Regulatory geography — UK and EU requirements diverge meaningfully. Tuum has invested in EU data localisation. Temenos has the broadest multi-jurisdiction coverage.
Ecosystem openness — Your core sits at the centre of everything. How well it integrates with your payments rails, KYC providers, and data layer matters as much as what it does natively.

At a Glance

Provider	HQ	Best For	Speed	Standout
Thought Machine	London	Complex product builds, neobanks	Medium–Long	Smart contract configurability; Gartner Leader 2025
Mambu	Amsterdam	Lenders, consumer fintechs	Fast	Composable model; wide connector marketplace
10x Banking	London	Banks reducing operational overhead	Medium	Managed SaaS; strong institutional backing
Temenos	Geneva	Traditional banks, phased transformation	Medium–Long	Deepest regulatory coverage; most deployed globally
Tuum	Tallinn	BaaS providers, multi-entity fintechs	Fast–Medium	Multi-tenancy; EU data localisation native
Ohpen	Amsterdam	Savings, investments, mortgages	Medium	Cloud-native specialist; not a generalist core
Skaleet	Paris	Neobanks, EMIs, PSPs	Fast	Maximum openness; cloud-agnostic architecture

Final Word

Your core banking platform will define your product velocity, your regulatory posture, and your cost to serve for years. The options available to UK and European fintechs today are genuinely excellent, but that makes the selection decision more nuanced, not easier. Know your model, know your timeline, and choose infrastructure that fits where you're going, not just where you are.

Next in the Partner Blueprint: Payments Infrastructure — the rails, processors, and orchestration tools that sit above the core and move money in real time.