An open notebook
just nhancv.
A little corner of the internet for things I learn, ideas I explore, and discoveries worth keeping.
Wander through the gardenA few paths in.
Follow your curiosityMobile & interfaces
Small screens, thoughtful interactions, and the details in between.
Cloud & systems
How services fit together, run, and keep running.
Blockchain
Transactions, contracts, and the mechanics underneath.
Tools & experiments
Useful tools, small discoveries, and things learned by trying.
Selected writing
All notes- A rounded TextField in Flutter
A compact styling note on filled inputs, border radii, padding, and focus states.
Mobile & interfaces - A three-tier web architecture on AWS
An older Terraform experiment in separating frontend, backend, and data access across two Availability Zones.
Cloud & systems - Building Bitcoin transactions with PSBTs and custom UTXOs
A historical BitcoinJS experiment covering four address families, fee estimation, and explicit input selection.
Blockchain / Tools & experiments - Testing ERC-4337 in a local environment
A small account-abstraction experiment: a local chain, a bundler, a mock paymaster, and a Safe smart account.
Blockchain / Tools & experiments - Understanding contract addresses: CREATE and CREATE2
Creation bytecode, constructor arguments, and the difference between a sender nonce and a deterministic deployment salt.
Blockchain
From earlier notes
Ideas worth revisiting- Deploying a contract with Truffle
A historical walkthrough of Ganache, environment-based wallet configuration, and Truffle migrations.
Blockchain - Working with Android runtime permissions
A historical permission-controller example, with explicit requests, result callbacks, and the limits of an all-permissions approach.
Mobile & interfaces - A small Android screen-touch tester
An earlier utility that marks touch positions and uses the Back button to clear or exit.
Mobile & interfaces