Migrating foundational software to the 21st century
We help teams build in Rust.
from Amsterdam with love
Mon – Fri 08:00 – 18:00 CET
We typically respond within one day.
Elias and Max are ready to walk the extra mile. They are efficient organizers and motivators, think in solutions and out-of-the-box, and never let you down.
We believe that now is the time for reliable software. Made in Europe
The latest updates from Defined Once Amsterdam HQ
All posts
The Direction of Safety-Critical Rust: Oxidize 2026
Known as 'The Applied Rust Conference', Oxidize focuses on industry, embedded and increasingly about using Rust in safety critical contexts.
Announcing the New Defined Once HQ!
To be able to grow further, Defined Once has moved its headquarters to the A'DAM tower, right across Amsterdam Central station.
We're joining the Rust Foundation's Rust Commercial Network (RCN)
Defined Once Engineering B.V. has joined the Rust Commercial Network as a founding member to stay in contact with Rust's commecial users and to give back to the Rust programming language.
And We're Live - Launching at RustWeek 2026
We're officially launching Defined Once at RustWeek 2026 in Utrecht. Here is who we are, what we do, and why we do it.
We share our vision through RFDs. Publicly tracked and open to be challenged
All RFDsThis document describes how to handle sensitive data during our work. It does not include novel ideas, but summarizes relevant rules of thumb, tools and example…
Source management with git allows for ample opportunity of dangerous, unhelpful or plain annoying experiences as a software engineer. While this is bad enough w…
A small collection of guidelines on writing software. Programs must be written for people to read, and only incidentally for machines to execute. — Gerald Jay …