Code & Systems | Engineering Blog by Olawale Lawal

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Stop Rolling Your Own Transaction Management in .NET

Stop Rolling Your Own Transaction Management in .NET

designing database transaction management in .net core using TransactionScope

Building Quorum: Architecture of a Multi-Tenant Approval Engine in Go

Building Quorum: Architecture of a Multi-Tenant Approval Engine in Go

Every team builds maker-checker from scratch. Quorum is a standalone approval engine in Go that handles concurrent vote serialization, durable webhook delivery via the outbox pattern, multi-tenant isolation, and real-time SSE updates.

Iterating a .NET CI/CD Pipeline From 12 Minutes to Under 5

Iterating a .NET CI/CD Pipeline From 12 Minutes to Under 5

I added automated API snapshot tracking to a four-service .NET backend and watched GitHub Actions build times go from 3 minutes to over 12.

BranchGuard: Stateless GitHub Automation for Smarter Branch Rules

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BranchGuard: Stateless GitHub Automation for Smarter Branch Rules

How I built a stateless GitHub App that evaluates configurable branch protection rules based on which files changed, with zero infrastructure dependencies.

Auto-Logging: Automating Away the "Please Turn On Debug Logs"

Auto-Logging: Automating Away the "Please Turn On Debug Logs"

A production observability platform that auto-enables verbose logging on errors and disables it when resolved. Built with Grafana, OpenTelemetry, and .NET.

Building CI/CD Pipelines for .NET Core on Github Actions

Building CI/CD Pipelines for .NET Core on Github Actions

Shipping features fast requires confidence and nothing builds confidence like a robust CI/CD pipeline. For .Net Core teams, Github Actions provides a powerful, integrated platform to automate everything from code commit to deployments. This guide walks through building a mature, efficient pipeline for .NET Core including intelligent caching, zero-downtime

Why your password is about to become obsolete

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Why your password is about to become obsolete

How many passwords do you have? If you’re like most people, you probably reuse the same password across multiple sites, maybe with a number tacked on the end or a slight variation. You know it’s not secure, but remembering 50 different complex passwords feels impossible. Here’s the

The API Diff Tool That Escaped the Monolith

The API Diff Tool That Escaped the Monolith

Three generations of a Swagger diff tool: from React SPA to embedded HTML to reusable NuGet packages. The patterns that made it work across ASP.NET projects.

Secure, Centralized Configuration in .NET Core with Hashicorp Vault

Secure, Centralized Configuration in .NET Core with Hashicorp Vault

When you're building even a handful of microservices, managing connection strings, API keys and secrets across multiple environments (dev, staging, uat, production e.t.c) can quickly get out of hand. Hard-coding values, checking JSON files into source control or juggling a dozen environment variables all invite mistakes

Why Your Phone's Battery Never Lives Up to the Hype

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Why Your Phone's Battery Never Lives Up to the Hype

You unbox a new phone boasting "all-day battery life", only to find yourself needing a power outlet on a random afternoon a few months later. It's frustrating and it's easy to feel like those marketing claims are a deliberate deception. But the trust is

The FinTech Staff Engineer: Translating Business Risk into Technical Architecture

The FinTech Staff Engineer: Translating Business Risk into Technical Architecture

A framework for fintech staff engineers to translate vague compliance mandates into concrete technical requirements, architecture patterns, and SDLC processes.

Building for the 1%: Engineering Handling for Exceptions and Disputes

Building for the 1%: Engineering Handling for Exceptions and Disputes

Payment engineers spend 80% of their time on 5% of transactions. Learn how to architect exception handling, dispute flows, and ledger reconciliation.

Harnessing PostGIS in .NET: Building Location-Aware Applications

Harnessing PostGIS in .NET: Building Location-Aware Applications

Spatial data (geographic coordinates, polygons and geometric shapes) opens a world of features such as "find the nearest coffee shop", geo-fencing alerts and mapping visualizations. PostgreSQL, when extended with PostGIS, provides a powerful, open-source spatial database. Combined with .NET and EF Core (via NetTopologySuite), you can effortlessly persist,

From Debugging to Design: How Thinking in Flows Makes You a Better Payments Engineer

From Debugging to Design: How Thinking in Flows Makes You a Better Payments Engineer

The Three Flows framework: funds, data, and reconciliation. Turn payment debugging from guesswork into forensic science.

The Map is Not the Territory: Navigating the Hidden Complexities of Payment Rails

The Map is Not the Territory: Navigating the Hidden Complexities of Payment Rails

Authorization and settlement are separate systems with separate timelines. Learn the real-world complexities of payment rails that documentation won't tell you.

Using Caddy as a Reverse Proxy with SSL Termination and Cloudflare in Docker Compose

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Using Caddy as a Reverse Proxy with SSL Termination and Cloudflare in Docker Compose

Caddy is a modern, lightweight web server with automatic HTTPs, easy configuration and built-in support for reverse proxying. In this guide, we'll show you how to: 1. Building a custom Caddy Docker image with the cloudflare plugin. 2. Configuring Docker Compose to use our built custom image. 3.

The Truth About 'Private Browsing'

The Truth About 'Private Browsing'

That little incognito icon, the one promising a secret digital corner, is one of the most misunderstood features on the internet. We've all used it, trusting in its veil of privacy but what if that veil is thinner than you imagine? Let's talk about what private

Coordinating Distributed Operations with Hazelcast HMap and AsyncContext in .NET

Coordinating Distributed Operations with Hazelcast HMap and AsyncContext in .NET

In modern microservices and distributed systems, ensuring coordinated access to shared recourses is critical. Hazelcast offers powerful distributed data structures and concurrency primitives out of the box. In this article, we'll explore how to leverage HMap in combination with AsyncContext in the Hazelcast .NET client to implement non-blocking,

Using Ocelot as an API Gateway in a .NET Core Microservices Architecture

Using Ocelot as an API Gateway in a .NET Core Microservices Architecture

Microservice introduce agility, scalability and autonomy for development teams but they also bring complexity in handling cross-cutting concerns like routing, authentication and load balancing across multiple services. An API Gateway centralizes these concerns, providing a single entry point for clients. In the .NET ecosystem, Ocelot is a lightweight, easy-to-configure API

Advanced Multi-User Authentication in .NET Core

Advanced Multi-User Authentication in .NET Core

When building modern multi-tenant or role-diverse systems in .NET Core, supporting different user types that each have difference in authentication behaviors, often goes beyond the standard SignInManager and UserManager. This article explores how to implement advanced authentication by extending ASP.NET Core Identity with custom managers and token providers for

Death to SMS OTPs!

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Death to SMS OTPs!

The familiar ping of a text message delivering a six-digit code has become the soundtrack of our digital lives. For years, SMS-based one-time passwords (OTPs) have been the default sentry guarding our banks accounts, emails and other online accounts. Unfortunately, this sentry is sleeping on the job and we'

Structured Logging in .NET with Seq: A Developer's Guide

Structured Logging in .NET with Seq: A Developer's Guide

Why Structured Logging? * Problem: Traditional text logs (e.g Console.WriteLine) are hard to query and analyze. * Solution: Structured logging emits logs as machine-readable key/value pairs and enables: * Filtering (e.g WHERE UserId = 123) * Correlation (e.g trace IDs across microservices) * Integration with dashboards (e.g Seq, Elasticsearch) Setting

Mastering TaskCompletionSource in C#

Mastering TaskCompletionSource in C#

Asynchronous programming is at the heart of modern .NET applications to enable scalable, responsive systems without blocking threads. While async/await and the built-in Task returning APIs cover most scenarios, sometimes you need custom asynchronous operations, particularly when bridging callback-based code, implementing complex synchronization primitives or exposing event-driven logic as