Hiring against the banks
Fintechs recruit from the same pool as the banks and big tech firms in the City and Canary Wharf. Senior engineers are expensive and slow to land.
Fintech software development · London
Fintech Software Development in London
Engineering for London payments, lending, wealth, insurtech and B2B finance teams — onboarding and KYB flows, Open Banking integrations, back-office tools and customer apps — built so your compliance team can see how everything works before they sign it off.
- Regulated steps handled by authorised providers
- Audit trails and access controls from day one
- Straight answers for your supplier due diligence
The problem
What slows London fintech teams down.
Rarely the idea. Usually the hiring market, the compliance loop and the number of providers in the stack.
Where engineering help pays off
- KYB and onboarding flows that reduce manual review
- Back-office tools for payments operations and exceptions
- Integrations with Open Banking, card and KYC providers
- Audit trails and outcome data your compliance team can use
Compliance questions arrive late
A feature is built, then someone asks how consent, record-keeping or complaints are handled — and it goes back for rework.
A provider for everything
Banking-as-a-service, card issuing, Open Banking, KYC and fraud tools each bring their own APIs, sandboxes, webhooks and failure modes.
Supplier due diligence
Bank partners and your own risk team want every supplier that touches customer data vetted. A supplier who cannot answer the questionnaire stalls the launch.
Operations on spreadsheets
Payouts reconciled by hand, documents chased by email, exceptions tracked in a shared sheet — because the customer-facing roadmap always wins.
Outcomes you cannot evidence
The Consumer Duty expects evidence of good customer outcomes, and that needs data your platform may not be capturing yet.
Who we build for
Software for London’s fintech segments.
Different licences, different providers, different risks. The engineering discipline is the same.
Money movement you can trace
Pay-ins, payouts and transfers with clear states, webhooks that are safe to receive twice, and an operations view of everything stuck in between.
Applications to decisions
Application journeys, affordability checks using Open Banking data, decision workflows and servicing portals — with every decision recorded.
Portfolios clients understand
Client portals, onboarding and suitability questionnaires, and reporting that explains performance and fees in plain language.
Quote, bind and claims tools
Rating and quote journeys, broker portals and claims intake for managing general agents and insurers working in the London Market.
Tools for finance teams
Invoice finance, spend management and payables products connected to Xero, QuickBooks and Sage, with KYB built on Companies House data.
New products beside core systems
Customer apps, staff tools and APIs for banks, brokers and building societies that need to launch something new without disturbing the core platform.
Regulation
Building for regulated products, without overstepping.
We are a software company, not an authorised firm or a compliance consultancy. Authorisation, the regulated activities themselves and the judgement calls stay with you and your advisers. What we bring is engineering that makes your obligations easier to meet — and easier to evidence.
If you are preparing for the FCA’s regulatory sandbox or an authorisation application, we can build the test product you need and document how it works. The Consumer Duty expects firms to evidence good outcomes across products and services, price and value, consumer understanding and consumer support; we build in the journey analytics, clear disclosures, and complaint and vulnerability flags that make that monitoring possible.
Where a feature involves a regulated activity — payment initiation, account information, e-money, credit — we integrate an authorised provider rather than trying to rebuild its licence in code. Your compliance team keeps visibility throughout: architecture decisions, data flows and access controls are written down as we go, not reconstructed afterwards.
- Consent and disclosure screens reviewed by your compliance team
- A record of who did what, and when, for every sensitive action
- Customer-outcome data captured for Consumer Duty monitoring
- Regulated activities delegated to authorised providers
Integrations
The integrations London fintechs rely on.
Most fintech products are a careful arrangement of providers. We build the orchestration, the failure handling and the operations tooling around them.
Open Banking, via providers
Account information and payment initiation through an authorised Open Banking provider — for affordability checks, account verification and pay-by-bank.
KYB with Companies House
Company profiles, officers and persons with significant control from the Companies House API, compared with what the applicant told you, then checked by your KYB provider and analysts.
Identity and KYC
Document and biometric checks through your chosen provider, with review queues for the cases it cannot decide automatically.
Cards and payments
Stripe for card acceptance and subscriptions, and card-issuing or banking-as-a-service partner APIs where the product needs accounts or cards.
API and integration work
Accounting platforms
Xero, QuickBooks and Sage connections for B2B products that need invoices, bills, payments and bank feeds kept in step.
AI in operations
Document extraction, transaction categorisation and case summaries for operations and compliance teams — with an analyst making every decision.
AI for fintech
How we work
How a fintech build runs with us.
The standard seven stages, with the compliance questions asked at the start — when changing an answer is still cheap.
- 01
Discovery
We map the product against its regulated activities, providers and customer journeys, and agree with your compliance lead which decisions need their sign-off.
Journey, provider and sign-off map
- 02
Strategy
Build or integrate for every component, provider sandboxes lined up early, and a release plan that fits your authorisation or partner-bank timetable.
Architecture, provider plan and quote
- 03
UX & architecture
Consent, disclosure and error screens designed with your compliance team, including journeys for customers in vulnerable circumstances.
Reviewed journeys and data-flow diagram
- 04
Development
Two-week sprints against provider sandboxes, code review on every change, separate environments, and no real customer data outside production.
Working software every sprint
- 05
Testing
The unhappy paths get the most attention: failed payments, duplicate webhooks, partial refunds, expired consents — plus security testing before release.
Test evidence for your change process
- 06
Launch
Released gradually behind feature flags and watched closely, with alerts and a tested way back if something misbehaves — all agreed in advance with your operations team.
A monitored, reversible release
- 07
Optimisation & support
After launch we fix, measure and improve — a support retainer, a roadmap of next features, or a clean handover to your own team.
Support plan or handover
Supplier due diligence
Ready for your supplier due diligence.
Before we touch production systems, your compliance, risk or procurement team will usually want to vet us — especially if a bank partner, your licence or your own outsourcing policy requires it. That process is yours to run. Our job is to make it quick and to answer plainly.
We will describe how our engineers access systems (named accounts, multi-factor authentication, least privilege, no shared logins), where data is processed and by whom, and how code is reviewed and deployed. Because engineering happens in both the UK and India, your DPO will want to know how any international transfer of personal data would be covered, and that is settled before anyone is given access. We will not claim certifications we do not hold; if your policy requires one, we will tell you at the start rather than at the end.
Your contract would be with Krapton IT Consultancy, a UK company. If your supplier terms include specific requirements, such as audit rights, exit provisions or certifications, raise them at the start and you will get a straight answer on each. Exit is simple in any case: the code, the infrastructure accounts and the documentation are already yours.
- Plain answers to your supplier questions
- Named engineer accounts with MFA and no shared logins
- Your requirements checked before any proposal
- An easy exit: you already own the code and the accounts
Engagement models
Ways fintech teams work with us.
A discovery sprint to map the product, providers and sign-offs, then a fixed-price build. For a roadmap measured in quarters rather than weeks, a managed team can work alongside your own engineers.
Discovery sprint
From £2,000 fixed fee
You have an idea or a problem, but not yet a scope you would trust a quote against.
- Workshops with your team
- Prototype or technical spike
- Written scope, plan and estimate
Fixed-scope project
Quoted after discovery
A defined build — an MVP, a rebuild or a feature set — with milestones and a fixed budget.
- Agreed milestones and deliverables
- Milestone-based billing
- A demo at the end of every sprint
Managed product team
From £9,500 per month
A small cross-functional pod — engineering, QA and delivery lead — that owns an outcome.
- One accountable delivery owner
- Sprint planning and reporting
- QA and code review included
Prices are in GBP. Every estimate is confirmed in writing after a discovery call — the figures above are where engagements start, not a quote.
Relevant work
Products we have designed and built.
A money-transfer and card app, a digital banking app and a multi-bank wallet — fintech products from our case studies, each covering the brief, the approach and the stack.
All case studiesFintech · Mobile
Sendora
Mobile-first money transfer and card app for a cross-border fintech.
React NativeNode.jsMapboxStripe
Read the case studyFinance · Mobile
Equity Bank
Digital banking app: accounts, bill payments, loans and investments.
React NativeNode.jsPostgreSQLAWS
Read the case studyFintech · Payments
e-Wallet
Multi-bank digital wallet with transfers, analytics and virtual cards.
React NativeNode.jsStripePostgreSQL
Read the case studyWhy Techsleight
What working with us is actually like.
How we work with fintech teams — the practices you can check, not a badge on a slide.
Product engineering, not ticket-taking
We ask what the software is for before we estimate it — and we will tell you when something should not be built, or should be bought instead.
AI where it earns its place
LLM features, retrieval and automation built with evaluation, guardrails and cost controls, and plain software where that is the better answer.
Full-stack under one roof
Design, frontend, backend, mobile, cloud and QA in one team, so nothing falls between suppliers.
UK-focused delivery
UK business hours, estimates in pounds, and a contract with a UK company. Our engineers are based in the UK and India.
Flexible engagement
A fixed-scope project, dedicated developers or a monthly retainer — and you can move between them as the work changes.
You own everything
Code, IP, cloud accounts and documentation are yours from day one. We sign an NDA before discovery if you need one.
Support after launch
We stay on for fixes, upgrades and new features, or hand over cleanly to your in-house team with the documentation to match.
FAQs
Questions we get asked.
Straight answers on scope, cost, timelines and how we work. If yours is not here, ask us directly.
Are you authorised by the FCA?
No. Techsleight Labs builds software; it is not an authorised firm and does not advise on law or regulation. Regulated activities are carried out by you or by the authorised providers we integrate, and we build and document the software around them so your compliance team can assess it.
How do you work with our compliance and risk teams?
Directly, from discovery onwards: we walk them through the design and the controls on video, and they can join any of the fortnightly demos. Day to day, delivery is remote and runs on UK business hours: a shared Slack or Teams channel, fortnightly demos and a written update every week.
Where are your engineers, and who can access production data?
Our engineers are in the UK and India. Who can access production data is agreed with you before any access is granted; it is common to keep developers out of production entirely and use anonymised or synthetic data elsewhere. Where access is needed, it is limited to named people and logged, and it is only granted once your DPO is satisfied with how the data is protected.
Can you help us prepare for the FCA sandbox?
We can build the prototype or test product you take into the regulatory sandbox, and document how it works, how data flows and how customers are protected. The application, the testing parameters and the conversation with the FCA stay with you and your advisers.
Do you connect to Open Banking directly?
We connect through an authorised Open Banking provider, which is how most products do it. We compare providers with you on bank coverage, reliability, data terms and cost, then build the consent journeys, reconnection flows and handling for banks that are temporarily unavailable.
How do you use Companies House data for KYB?
We pull the company profile, officers and persons with significant control from the Companies House API and compare them with what the applicant has told you, sending mismatches to an analyst rather than clearing them automatically. Companies House identity verification for directors and PSCs is a useful extra signal, but the register does not replace the checks your KYB provider and policy require.
How do you handle PCI DSS for card payments?
By keeping card data out of your systems wherever possible: hosted payment fields or tokenisation from Stripe or your acquirer mean card numbers never touch your servers. Your acquirer or a QSA confirms your compliance level; we design and document an architecture that keeps your scope small.
How much does fintech software development cost?
Discovery — mapping the product, providers and sign-offs — starts from £2,000 and ends in a fixed price for the build, billed by milestone. For continuous roadmap work, a managed team starts from £9,500 a month. Provider fees — Open Banking, KYC, card issuing — are separate, and we estimate them with you.
Can you work on our existing fintech platform?
Yes. The first step is a review of the codebase, infrastructure, access controls and release process. We then deal with the risks that matter most — flaky integrations, missing audit trails, manual deployments — before adding features, and your engineers stay in control of what gets merged.
Who is our contract with, and in which currency?
Krapton IT Consultancy, which trades as Techsleight Labs; its registered office is 128 City Road, London EC1V 2NX. Quotes and invoices are in pounds, and we will sign your NDA before discovery and work through your supplier agreement with you.
Start a project
Building or fixing a fintech product in London?
Tell us what you are building, which providers are involved and who needs to sign it off. A reply follows within one working day, with the questions that matter and a sensible first step.
What happens next
- 1A senior engineer reads your brief within one working day, and replies with questions or a first view.
- 2A 30-minute call to understand the goal, constraints and what good looks like — no sales script.
- 3A written proposal with scope, milestones, team and a GBP estimate you can take to your board.
Techsleight Labs is a trading name of Krapton IT Consultancy.
Explore