Fintech
Fintech development
Card products, payments, lending and account data — built so the reconciliation, the audit trail and the authorisation question are part of the plan rather than a discovery in month four.
From £75/hrAn estimate before any work startsOne developer, start to finish
01
In fintech the hard part is rarely the feature. It is everything that has to be true before it can ship.
A payments flow is a week. Idempotency, reconciliation, a ledger that balances, an audit trail somebody else can read, and a clear answer on whether you are authorised or riding somebody else's permission — that is the project.
02
What actually gets built
Card and spend products
Issuing, controls, limits and the statement that has to agree with the ledger. Including the parts nobody demos: declines, disputes and refunds.
Payments and reconciliation
Idempotency so a retry does not take the money twice, a queue so an outage means delayed rather than lost, and a reconciliation that someone can actually run at month end.
Open banking and account data
Pulling account and transaction data through a provider, and the consent lifecycle that goes with it — which is usually where the real complexity sits.
The audit trail
Every decision reconstructable afterwards. It is the first thing a regulator, an acquirer or a serious customer asks for, and the hardest thing to add later.
03
How the work runs
You describe it
Two sentences is enough to start. What you are building, who it is for, and which rule or buyer is forcing the shape of it.
A scope and a price, inside 24 hours
What is in, what is deliberately out, what each stage costs and what it depends on. Where a regulator or a procurement process sets the timeline, that goes in the plan rather than being discovered in week six.
Built in the open
Your repository from the first commit, deployed somewhere you can see it from the first week.
Handed over properly
Your accounts, your keys, your infrastructure, and a README that assumes the reader is not me.
- Rate
- From £75/hr
- Scope and price
- Inside 24 hours
- Written by
- The person who scoped it
Authorised, or riding somebody else's permission? That one answer changes the architecture, the timeline and the cost. It is worth settling before anything is built.
Start a project →05
Who this has been done for
TrueDebt
Verified debt settlement for Nordic lenders, replacing collection calls with a structured process. Built for a stake in the company rather than an invoice — which is the strongest thing we can say about believing in it.
Onzo — in build
A corporate card and business spend product, and Midnyte's own: the native iOS app and the platform behind it. Pre-launch at the time of writing.
Eleven years and more than three hundred projects behind these.
Common questions
Do you handle the regulatory side?
Not as a licence application — that is your lawyer's and your compliance adviser's work. What gets handled here is the engineering the regime implies: the audit trail, the data retention, the consent lifecycle, and building so a permission you do not yet hold can be added without a rewrite. There is a page on authorisation and open banking.
Can you work with our existing payment provider?
Yes, and that is usually the right call rather than switching. The integration is written with their shape kept at the boundary, so a version being deprecated or a field changing is a change in one file — which matters more in payments than almost anywhere else.
How do you handle money correctly in code?
Integer minor units, never floats; idempotency keys on anything that moves value; a ledger that is append-only and balances; and reconciliation as a feature rather than a spreadsheet someone keeps. These are not preferences, they are what stops a rounding error becoming a liability.
04
Tell me what you are building
Two sentences is plenty. You get back a scope, a price, and an honest view of which permission question has to be answered first.