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Practical System Design: The Quiet Elegance of Boring Architecture

Junior engineers often assume that impressive system design requires a complex web of microservices, event streaming through Apache Kafka, CQRS patterns, and distributed consensus mechanisms running across every cluster.

When an Autonomous AI Agent Left Its Owner a $6,500 AWS Bill Scanning DN42

Over the past few days, the DevOps and networking communities have been buzzing about a rather tragicomic incident. An operator confidently gave an autonomous AI agent an AWS API key with full administrator access. The mission seemed simple: join and scan DN42. A few days later, the operator woke up to a $6,531.30 AWS invoice, declared bankruptcy, and took to the DN42 mailing lists and Matrix channels begging for cryptocurrency donations.

Software Architecture: Monolith, Microservices and the Distributed Monolith Trap

Many young Backend programmers tend to view software architecture models as a religion or a measure of skill. Microservices are often revered as the pinnacle of technology, Monolith is labeled as outdated, while Distributed Monolith - the worst state - is often mistaken for real microservices.

MySQL vs PostgreSQL from an interview perspective: Read/Write-Heavy and MVCC mechanism

MySQL vs PostgreSQL is a classic topic in backend engineer interviews. The interviewer asks this question not to hear you list superficial features like “Postgres supports JSON better” or “MySQL is more popular”. They want to assess your in-depth understanding of storage architecture, transaction control mechanisms, and how the system operates under various high-load conditions.

Agent = Model + Harness: Do not put an F1 engine into a brakeless bus

At the end of last year, I created a bot that ran in the background to automatically read menus from partner restaurants sent in PDF/Excel format, then parsed them into a Go struct to load into the Menu Service database.

When to use cache and when not to

Backend , Golang , System design

There is a production bug that I still remember vividly: user A cancels an order, but the app still displays “delivering” for the next 10 minutes. Support receives 30 tickets in one morning. The reason: cache TTL is 10 minutes, but no one invalidates it when the order status changes.