What I learned building a self-corrupting file format in Rust
Rust engineering notes from decayfmt: typed errors with no unwrap, parsing untrusted bytes without panicking, and writing decay without bricking the file.
Arav Panwar Founder at Vespertil Technologies · Hyderabad, India
Writing
2026
the weakest link just got 630 gigabytes bigger
Notes on the Tata Electronics leak, and on building a manufacturing boom faster than the security floor underneath it.
A file format that destroys itself a little every time you open it
decayfmt is a file format where every open permanently corrupts the file, on purpose, with no recovery short of a backup. I can explain how it works much more clearly than why it exists.
Context 'Engineering' vs Prompt 'Engineering'
Phrasing one prompt well is a small skill. The real work is the schemas, handoff docs, and decision logs a stateless model has to work inside.
An options pricer that does not flatter itself
Pricing American options on the same paths you fit the exercise rule on flatters the result. Scoring on fresh paths gives an honest lower bound instead.
Pushing an RTX 4050 with an options pricer
I set out to saturate a GPU's compute. Two kernels later, the lesson was that memory and sequential steps, not raw math, are usually what gets in the way.
Filtering GitHub Archive without the disk space for it
Half a terabyte of GitHub events, a laptop with 100 GB free, and one repo I actually wanted. Streaming and filtering the firehose without ever storing it.