The Engineering Journal

Field notes from buildingprivacy-first software.

Long-form essays on Android engineering, mobile architecture, on-device AI, and the small decisions that compound into trustworthy products.

Volume: 02
Cadence: Slow
Stack: Android

June 12, 20266 min readci
opentia: How We Stopped Running the Entire Test Suite on Every Commit
Most CI pipelines run every test on every change, even a typo fix in a README. We built opentia, a single-file Test Impact Analysis script that figures out which tests a diff actually touches — and skips the rest, safely.
testingpythondevops
April 28, 20264 min readandroid
How We Parse Bank SMS On-Device Without Sending Your Data Anywhere
Most finance apps send your transactions to a server for processing. We built a regex-based SMS parser that runs entirely on your phone — here's exactly how it works.
privacykotlinnlp