# Backend & API Development > Selected work demonstrating this service. - [Delivered 8 Power BI projects with comprehensive manuals, integrating Microsoft Power BI tools with NodeJS API and Python FastAPI for effective data analytics and visualization.](https://advisory.engineer.company/portfolio/delivered-8-power-bi-projects-with-comprehensive-manuals-10/) - [Directed full‑stack GIS map development, overseeing PostgreSQL, Mapbox, ReactJS, and NodeJS to deliver an integrated solution.](https://advisory.engineer.company/portfolio/directed-full-stack-gis-map-development-overseeing-postgresql-25/) - [Led the development, deployment, and support of over 30 GIS projects, demonstrating expertise in PostgreSQL, Bash, Python, JavaScript, GDAL, ArcGIS, PostGIS, and Mapbox technologies.](https://advisory.engineer.company/portfolio/led-the-development-deployment-and-support-of-over-35/) - [Developed a Data Analytics reporting system, increasing quarterly software revenue by 400% through Python‑based PDF reports.](https://advisory.engineer.company/portfolio/developed-a-data-analytics-reporting-system-increasing-quarterly-44/) - [Migrated the HTTP API from Fiber to Huma v2 — 649 paths and 760 operations — reaching and holding 100% parity between the routes the server registers and the OpenAPI description it publishes.](https://advisory.engineer.company/portfolio/migrated-the-http-api-from-fiber-to-huma-60/) - [Set the platform's founding decisions in the weeks after the repository opened in November 2025 — the layering, database‑first data access and the zero‑warnings bar — and they still hold nine months on.](https://advisory.engineer.company/portfolio/set-the-platform-s-founding-decisions-in-november-2025-80/) - [Built a layered automated test suite — 981 Go tests, 543 frontend and browser specs, 494 SQL behavioural tests — with mutation testing, property‑based tests and an accessibility gate.](https://advisory.engineer.company/portfolio/built-a-layered-automated-test-suite-across-four-layers-94/) - [Built the payments and entitlements layer — Stripe alongside Apple and Google in‑app purchase — gating the directory, search and export through an 11‑table access model checked on the server.](https://advisory.engineer.company/portfolio/built-the-payments-and-entitlements-layer-96/) - [Built the loyalty and reputation system — 67 functions over a 31‑table ledger, with leagues, badges and a redemption shop — taking a row lock on the balance to close the double‑spend window.](https://advisory.engineer.company/portfolio/built-the-loyalty-and-reputation-system-105/) - [Built the platform's social layer — posts, feed, groups, mentions, a follower graph and an occasions digest — on the same function‑first data layer as the rest of the product.](https://advisory.engineer.company/portfolio/built-the-platform-s-social-layer-106/) - [Built the hiring marketplace and the seafarer career workspace — 151 stored functions across 48 tables — covering vacancies, applications, certificates, rank progression and verified sea time.](https://advisory.engineer.company/portfolio/built-the-hiring-marketplace-and-career-workspace-107/) - [Held the generator to 981 test cases at a 92% branch‑coverage floor with warnings treated as failures, and asserted idempotence by running the whole build pipeline twice from an empty file and requiring the second pass to change nothing.](https://advisory.engineer.company/portfolio/held-the-generator-to-964-tests-and-a-coverage-floor-145/) - [Selected every rule the Python linter has as an error, working through 1,815 findings to reach zero, with each of the few exemptions carrying a written reason and two of them backed by a checker instead of a comment.](https://advisory.engineer.company/portfolio/enabled-every-python-linter-rule-as-an-error-147/) - [Adopted Swift 6 complete strict concurrency with no actors, bridging a blocking C event loop to the main actor through one producer, one consumer and one ordering — after establishing that a task per event loses the ordering the interface depends on.](https://advisory.engineer.company/portfolio/adopted-swift-6-strict-concurrency-over-a-c-event-loop-156/) - [Wrote a parser that reads the real 7,308‑line C header and verifies every call site, every enum constant and that every pointer‑owning class is final, after a hand‑written placeholder header let calls to three removed functions compile, link and crash.](https://advisory.engineer.company/portfolio/wrote-a-parser-that-verifies-every-ffi-call-site-157/)