Financial Software Development Where Every Cent Is Accounted For
Financial software is ordinary software with one unforgiving requirement: the numbers have to be right every time, and you have to be able to prove how they got there. Rounding errors, duplicated payments and silently failed syncs are bugs anywhere else; here they are money.
We build billing systems, payment flows, internal ledgers, reconciliation tools and financial reporting for businesses and fintech products, on top of licensed providers such as Stripe and Plaid rather than around them.
This is for you if
- ✓You need billing, invoicing or payment flows your current tools cannot model
- ✓Month-end means exporting from three systems and reconciling them in a spreadsheet
- ✓You are building a fintech product and need the money parts done properly
- ✓You need an audit trail that shows who changed what, and when
This is probably not for you if
- ✕You want to hold customer funds, lend, or issue cards without a licensed partner — that needs a bank or a regulated provider, not just software
We would rather tell you now than take the project and disappoint you.
Worth knowing: The cheapest way to stay out of regulatory trouble is to never touch what you do not need. Card details entered into Stripe's hosted fields keep you in the smallest PCI scope; identity checks run by a provider keep sensitive documents out of your database. Good financial software is often defined by what it deliberately never stores.
What you get
Money handled correctly
Amounts stored as whole numbers in the smallest currency unit, the currency kept with every amount, and rounding rules written down instead of left to floating point.
A real ledger
Double-entry records where every movement has a matching entry, so any balance can be rebuilt from history.
Payments that never double-charge
Idempotency keys on every payment request and webhook, so a retry or a repeated event cannot charge someone twice.
Reconciliation
Payments, payouts, bank lines and invoices matched automatically, with exceptions sent to a person instead of buried.
Audit trail
An append-only log of who changed what and when, which is the first thing auditors and acquirers ask for.
Reporting and exports
Revenue, deferred revenue, payouts and fees calculated from the ledger, with exports your accountant can use.
What we build for finance teams and fintech products
- Billing and invoicing — Usage-based or tiered pricing, proration, credit notes and dunning, on Stripe Billing or a custom engine when your pricing is unusual.
- Payment flows — Checkout, payouts and marketplace splits through Stripe Connect, including the onboarding and verification steps the provider requires.
- Bank and accounting data — Bank account data through Plaid, and two-way sync with QuickBooks or Xero so finance keeps working in the tools it knows.
- Financial reporting automation — The month-end spreadsheet replaced by scheduled reports built from the same data the business runs on.
- Internal finance tools — Spend approvals, commission calculators, loan and repayment schedules, and cash position dashboards.
What we will not do
We are not a bank, a money transmitter or a compliance firm, and we do not pretend to be. Holding customer money, lending and issuing cards all require a licence or a regulated partner, and we build on those partners rather than around them. If your product needs legal advice on licensing, get it before the build, not after.
What we build it with
Licensed providers for moving money, and boring, strict technology for recording it.
Payments
Stripe, Stripe Connect and Billing, PayPal
Bank data
Plaid
Accounting
QuickBooks Online and Xero APIs
Back end
Node.js and TypeScript, Postgres with strict constraints
Reporting
SQL, scheduled jobs, CSV and PDF exports
Security
Role-based access, audit logs, encrypted backups
Hosting
Vercel or Cloudflare, in your account, not ours
Testing
Automated tests on every calculation, including refunds and edge cases
Not sure whether custom financial software is what you actually need? Send over what you are trying to fix and we will tell you straight — including if a smaller job would do it.
Ask us first →How it works
Map the money
Every flow of money and every number the business reports, written down with where it comes from.
Fixed quote
A fixed price per phase, with the riskiest flow built and tested first.
Build with test cases
Calculations checked against worked examples your finance team agrees with before anything ships.
Launch in parallel
The new system runs beside the old process until a full cycle reconciles to the cent.
Work you can check
Real work that uses the same skills. Every card links to something you can open and inspect yourself.
Pixel & Oak POS
Billing, recipe-based stock, rider cash settlement and shift close for restaurants. Runs every day at a restaurant in Karachi.
Headless ShopifyPlayers Towel
A Next.js store with a towel designer. Every order reaches Shopify as a draft order through the Admin API, with live carrier shipping rates.
Questions
How much does financial software development cost?
Focused tools such as a billing engine, a reconciliation system or a reporting pipeline start at $15,000. Full fintech products usually run $40,000 and up, built in phases with a fixed price on each.
Is it PCI compliant?
We design so card details never touch your servers, using Stripe's hosted payment fields or checkout. For most setups that means the shortest PCI self-assessment questionnaire, SAQ A. The attestation is still yours to sign, and we document the setup to make that straightforward.
Can you integrate with banks?
Through aggregators such as Plaid for account data, and through Stripe or a banking-as-a-service partner for moving money. Direct bank integrations exist but usually need a commercial agreement with the bank first.
How do you prevent calculation errors?
Whole-number amounts, explicit rounding rules, double-entry checks that refuse to save an unbalanced transaction, and automated tests on the calculations themselves, including awkward cases like a refund of a partial refund.
Do you work with startups or established companies?
Both. Startups usually need the money parts of a new product built properly. Established businesses usually need the spreadsheets between their systems replaced.
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