Selected work

We would rather show two things in depth than list twenty logos. One long-running client engagement, one product we engineer and support end to end — and an engineering note on the hardest problem inside it.

Global Security Devices

Software for an Irish manufacturer of intruder alarm and access control systems

Sector: Physical security — intruder alarms, access control
Relationship: Ongoing — we handle their software activities
What it demands: Reliability with physical-world consequences

Alarm and access systems don't get to fail quietly. Working for their manufacturer taught us habits — conservative dependencies, monitored everything, rehearsed recovery — that we now apply to every line we write. The specifics of their systems are theirs to talk about, not ours.

Aha Invoice

A product we engineer and support: bookkeeping small businesses can defend

Status: In production
Shape: Multi-tenant SaaS — web, mobile, tablet and desktop (macOS & Windows)

Invoices, quotes, expenses, VAT breakdowns, sixteen reports — and underneath, the part we care most about: an append-only, tamper-evident audit trail, immutable issued invoices and period locks, so the books can stand up to the person checking them.

Read the product story

Engineering note: a tamper-evident audit trail

How Aha Invoice makes silent edits to the books detectable

Sequence-chained audit records, server-side signing, a daily integrity check and write-once retention — written up for engineers who want to see how we actually think.

Read the note