Developer Blog

Practical guides for everyday dev work.

13 hands-on articles on Java, Spring Boot, AWS, SQL & JSON — written by developers, for developers.

🔐Security
How JWT Authentication Works — A Developer's Guide

A clear explanation of JSON Web Tokens from first principles: structure, signing algorithms, standard claims, and the security mistakes that get teams into trouble.

Spring Boot
Cron Expressions in Spring Boot @Scheduled — Complete Guide

Master Spring Boot scheduled tasks with @Scheduled and cron expressions. Covers fixedRate, fixedDelay, the single-threaded scheduler trap, timezone configuration, externalised config, and testing strategies.

🗃SQL
Why SQL Formatting Matters in Code Reviews

How consistent SQL formatting improves code review quality, actively reveals logic bugs, and makes complex queries maintainable. Includes before/after examples and enforcement strategies.

📦Encoding
Base64 Encoding in Real Projects — When, Why and How

Base64 appears in HTTP Basic Auth, JWTs, data URIs, file upload APIs, email attachments, and TLS certificates. This guide covers when to use it and — just as importantly — when not to.

.*Regex
Regex Cheatsheet for Java and JavaScript Developers

A practical regex reference: character classes, quantifiers, named groups, lookahead, common patterns for email, dates and URLs, and the pitfalls that catch developers out.

📬AWS · SQS
How to Handle Dead Letter Queues (DLQ) in AWS SQS

A complete guide to DLQs: how maxReceiveCount and visibility timeout work, Spring Boot @SqsListener integration, CloudWatch alarms, and redriving failed messages.

🔁Spring Boot · AWS
Spring Boot SQS Retry Strategy — Exponential Backoff & DLQ

Production-grade SQS retry in Spring Boot: exponential backoff with jitter, visibility timeout extension, idempotent consumer design, and separating transient from permanent failures.

Java
Java 21 Migration Guide — Virtual Threads, Records, Sealed Classes & More

A practical guide to migrating production Spring Boot apps to Java 21: virtual threads, records, pattern matching switch, sealed classes, sequenced collections, and the APIs that now fail at run time rather than at compile time.

🤖AI · Architecture
Designing AI API Integrations That Survive Provider Churn

Model names, prices and rate limits change every few months. The interface seam, tiered routing, retry-and-failover, and cost patterns that outlive them — and why a region name is not a data-residency guarantee.

Data Engineering
Databricks vs Apache Spark — Performance, Cost & When to Use Which

What Photon actually accelerates, Delta Lake on open-source Spark, how to work out cluster cost for your own numbers on AWS ap-south-1, SQL dialect differences, and the decision framework for choosing between the two.

⚖️JSON
JSON Comparator Explained with Examples — How JSON Diffing Works

Structural vs semantic diff, key ordering, array comparison strategies (position-based, LCS, key-based), JSONPath targeting, and real-world examples including webhook payload changes.

📂JSON · Performance
How to Compare Large JSON Files Efficiently

Hash-based comparison, a Jackson streaming diff that really does hold memory flat, jq on the command line, key-indexed array comparison, and PostgreSQL JSONB when the files get big.