Backend Engineer
Backend engineer · microservices, cloud & AI
I design and build solid backend systems — microservices, data pipelines and cloud platforms — always with an eye on AI. I also craft free tools for developers and Italian users.
The tools on this site follow one simple idea: do one thing, do it well, and explain how it works. No account, no usage limits, no data collected.
Every computation — a hash, an IBAN check, decoding a token — happens on your device. No server receives what you type, so there is nothing to store and nothing that can leak.
No account, no trial period, no daily quota. The site is supported by advertising, kept out of the areas where you actually work with the tool.
Every tool has a page describing the algorithm, its edge cases and what the result does not prove. The blog articles go deeper into the same mechanisms, starting from the code that implements them.
Generators, validators and decoders for developers, plus tools for Italian standards such as IBAN and VAT numbers.
Generate the Italian fiscal code from personal data, or validate and decode an existing one. Available in the Italian version of the site.
Check whether an international IBAN or an Italian VAT number (Partita IVA) is well-formed, right in your browser. No data sent to any server.
Decode and inspect JWT tokens in your browser. Optional HS256 signature verification. No data sent to any server.
Create strong, random passwords right in your browser. No data sent to any server.
Compute MD5, SHA-1, SHA-256, SHA-384 and SHA-512 hashes of a text, right in your browser. No data sent to any server.
Generate UUID v4 and v7 right in your browser — nothing is sent to a server.
Deep dives on backend engineering, application security and Italian standards. Written from the implementation, with verified examples.
Base64url is not encryption and decoding is not verifying. Token structure, the classic attacks (alg none, RS256/HS256 confusion) and a server-side verification checklist.
Entropy measures the process that generated the password, not the string you are looking at. With the numbers: what a bit is worth, why "one uppercase and a symbol" makes things worse, and what actually works.
Collisions, preimages, the avalanche effect. Why MD5 is unusable for signatures yet legitimate for cache keys, and why SHA-256 is the wrong choice for passwords.
My name is Francesco Margiotta Casaluci and I am a backend engineer. At work I design and build microservices in Java and Spring Boot, data pipelines and cloud-native architectures orchestrated on Kubernetes; lately I have been working on agentic platforms and AI system integrations.
This site is where I write down what I learn by implementing it. The tools are the practical half, the articles are the half that explains why they work the way they do — and, more often than you would expect, what they do not guarantee.