The Check That Cannot Fail and 9 Rules for Real Verification
Have you ever looked at a dashboard full of passing tests and felt a sudden wave of suspicion? You probably should.
Notes on software engineering
Things I learn
building systems
Distributed systems, workflow orchestration, PostgreSQL and the things I learn building durable software.
- 2026
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3 min read
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Agentbus has made my life much more interesting
Three sessions, one the trader, the other is the sentinel (chief financial officer) and the third one is the audit. here is the audit's comments on communication between dev team and the CFO.
1 min read -
Market Making 101: How to Get Paid for Being Patient
A practical tutorial on passive market making — the trading method where you never predict the market, never chase a chart, and earn your money from the width of the spread.
9 min read -
Futex: Silence is a denial
On building a human-in-the-loop control plane for agents that can spend money, grant access, and delete things. — 0.
19 min read -
RevolutX, Good, Bad, Ugly
A technical and product review of Revolut's crypto exchange, from building an automated market maker on it — the documented behaviour, the undocumented behaviour, the arithmetic that decides…
16 min read -
RunFlow: building a place to run code you don't trust
- I should declare my position up front, because it colours everything below. I did not set out to build a container platform.
12 min read -
Building TokenGate: a meter that would rather overcharge you than lose the count
Bias declared up front, same as last time: TokenGate is mine. I designed it, I wrote it, I run it in production, and I have every commercial incentive to tell you it is wonderful.
13 min read -
I Built My Own CI/CD, and the Interesting Part Wasn't the CI
On replacing GitHub Actions with something that owns almost nothing — and why that turned out to be the whole point.
21 min read -
Nature’s Pinocchios
disclaimer : AI helped me to generate most parts of the text and make it more readable. The Deceptive Nature of the Animal Kingdom: Instinct or Intent?
4 min read - 2025
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The Shape-Shifter: Why AI-Driven Polymorphic Attacks Keep Me Up at Night
We used to have it relatively easy. When I first started paying attention to cybersecurity, malware was static. It was a specific file, with a specific "fingerprint" (hash).
2 min read -
Highway Workflow Engine
The Bank-Grade, Postgres-Native Workflow Engine. Highway is a durable workflow orchestration engine designed for systems where data integrity is non-negotiable .
3 min read -
Zero Dependency Context Aware Command Line Project Management
Code Agent Optimised Issue Tracker / Zero Dependency Context Aware Command Line Project Management 🤖 + = 🚀 I built a command-line issue tracking system for software development projects.
1 min read -
issue.db / your issue tracker in your repo
So this was this week's side project: issue-queue.readthedocs.io here is the workflow: I hope you find it useful.
1 min read -
Authorisation for Humans - A complete RBAC library
Auth is a RBAC lib I started back in 2015, when I badly needed something simple and quick. Since then, developers have download it hundreds of thousands of times, indeed, Pyhton Software Organisation…
1 min read -
Castle vs. Moat
This is the classic "Castle vs. Moat" debate in security architecture. While Docker provides a Moat (isolation from the host machine), the Sandbox provides the Code of Conduct (rules for what happens…
1 min read -
Circuit breakers needs durable state
I just noticed that I have missed a big point during the design phase of my workflow engine! I Leonard that, proper circuit breakers must have a durable state in a proper database.
1 min read -
Critical lessons from implementing a highly complex workflow system
- Transaction Boundaries are Sacred: When spawning child tasks, the parent MUST commit its transaction before children become visible to workers.
1 min read -
Building Datashard: Solving Data Corruption in High-Concurrency ML Workflows
I've been working on Highway, a Strict Atomic Workflow Management System that handles massive amounts of log data from multiple concurrent processes.
2 min read -
A new Article about what I am doing
I just published this article medium.com/@erlang/bank-grade-workflow-engine
1 min read -
A comparison of advanced workflow engines
Feature Highway Workflow Engine DBOS (from Demos) Apache Airflow Tork — — — — — Core Philosophy Decoupled Library . A resilient engine you integrate into your app. Integrated Framework .
2 min read