Davirson Novoa Ramírez

Own product — designed, built and operated

• Multi-user model on Postgres with a row policy on 34 tables: the conversion required rebuilding 22 primary keys that identified rows without the user, and pushing the user inside the foreign keys so isolation did not rest on the policy alone.
• Eight CI gates judged by exit code: types, format, lint, 526 tests, build, dependency audit, a guard that hunts personal data inside the built artifact, and a smoke test requiring the anonymous role to be denied across all 55 tables and views.
• A public demo running the five real screens over 120 seed-generated days that never queries the database; a test walks the runtime import graph and fails if any reachable module gets to the data client.
• Day logging in one form and one button, with eight independent writes, an on-device draft and send queue to survive losing signal, and a purpose-built number reader because a browser number field was storing expenses divided by a thousand.
• Hand-written SVG charts, no library, with contrast validated in light and dark and states separated by shape as well as color.

Market data platform — designed, built and operated

• Watermark-based incremental ingestion from 4 sources (Tiingo, Coinbase, Kraken, FX) into a three-layer PostgreSQL warehouse: 48 assets and more than 58,000 candles, idempotent and resumable.
• 89 automated dbt data-quality tests plus 171 Python unit tests; the pipeline fails before publishing bad data, not after.
• No-look-ahead backtesting engine with 70/30 out-of-sample validation over 1,392 strategy variants: only 13% of the in-sample winners survived the blind window.
• FX decomposition for Latin American ADRs, separating company performance from the currency move through the identity (1+r_USD) × (1+r_FX) = (1+r_local).
• Daily orchestration on GitHub Actions with a rate-limit circuit breaker, running on zero-cost infrastructure.

M.Sc. in Economics thesis, Javeriana — reproducible research end to end

• Purpose-built open-data downloader with a verifiable manifest: nineteen sources (financial supervisor, statistics office, ICT and education ministries, national map), row counts verified against the source, metadata-driven typing and a sha256 per file.
• Dimensional warehouse in dbt on DuckDB: department, municipality and period dimensions, financial inclusion in long form by product block, and tests that reconcile each department total with the sum of its municipalities.
• Geographic keys resolved to the municipal code with 100% coverage across the 34 quarterly cuts, and the splice between the supervisor's two tables measured quarter by quarter.
• A financial-inclusion index by dimension and annual panels at department and municipality level, with an explicit battery against spurious correlation. Public logbook of mistakes and wins.