Sonnet Code
Industry · Regulated

Software engineering for Finance & Banking.

Banking-grade software without the big-four consulting bill.

We build software for finance teams that have no margin for error — core banking integrations, ledger systems, regulatory reporting, and customer-facing portals. We know what a regulator-ready audit trail looks like, and we write code that survives one.

Let's talk

Jump-start your Finance & Banking

Tell us a bit about what you're building. We reply within one business day.

By submitting this form you agree to our privacy policy. No spam, no sharing.
Finance & Banking in production
Why Sonnet Code for Finance & Banking

The bar we hold ourselves to.

Audit-trail-first design

Append-only ledgers, immutable event logs, and reconciliation by construction — not retrofitted after the first audit finding.

PCI & SOX-aware

We've shipped under PCI-DSS and SOX scope. We don't hand-wave on encryption boundaries, key rotation, or change management.

Numbers that reconcile

Balance calculations, fx conversions, and fee logic are tested to the cent. Money bugs don't ship.

What we build with Finance & Banking

Finance & Banking work, shipped.

Core banking integrations

Connecting modern product surfaces to legacy core banking systems without rewriting the core itself.

Customer portals & mobile banking

Secure, accessible customer-facing applications built on proven auth, fraud, and compliance primitives.

Regulatory reporting pipelines

ETL and reporting systems for CCAR, Call Reports, and jurisdictional equivalents — with the audit trail built in.

Fraud & risk tooling

Real-time fraud detection, risk scoring, and adjuster workbenches that combine ML with rule-based controls.

Stack

Inside our Finance & Banking practice.

PostgreSQLGoPythonKafkaAWSSnowflakeTerraformOpenTelemetryPCI-DSS

Ready to get started with Finance & Banking? Fifteen minutes is all it takes.