# Reliability & Backups > Selected Engineer ApS work demonstrating Reliability & Backups — the achievements that prove it. - [Architected, created, and managed 100 PostgreSQL, MS SQL, and Google BigQuery data warehouse databases with primarily GIS and time‑series data, optimizing performance and scalability.](https://software.engineer.company/portfolio/architected-created-and-managed-100-postgresql-ms-sql-12/) - [Automated GIS SaaS application deployment, data processing, and reporting system using GitHub Actions CI/CD, Python, Bash, and SQL.](https://software.engineer.company/portfolio/automated-gis-saas-application-deployment-data-processing-and-16/) - [Automated delivery of 20 GIS data pipelines and app data ETL processes, streamlining infrastructure automation and reporting.](https://software.engineer.company/portfolio/automated-delivery-of-20-gis-data-pipelines-and-17/) - [Led the software development of a GIS map application, driving revenue growth by 10x and positioning the product as a primary data asset.](https://software.engineer.company/portfolio/led-the-software-development-of-a-gis-map-24/) - [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://software.engineer.company/portfolio/led-the-development-deployment-and-support-of-over-35/) - [Administered 40 websites on Ubuntu Linux hosting servers with Apache and Nginx, ensuring high availability and performance.](https://software.engineer.company/portfolio/administered-40-websites-on-ubuntu-linux-hosting-servers-53/) - [Architected, developed, implemented, supported infrastructure, data processing, and the map application for 2 years non‑stop without any weekends, holidays, or vacations, 10–14 hours a day.](https://software.engineer.company/portfolio/architected-developed-implemented-supported-infrastructure-data-processing-and-55/) - [Generated the API contract outward from the database — OpenAPI, a 44,076‑line typed TypeScript client, 61 mock handlers and the limits the UI enforces — with a guard at every hop that fails on drift.](https://software.engineer.company/portfolio/built-a-request-schema-validation-contract-with-automated-61/) - [Built email as a platform capability — three providers with failover, delivery webhooks, send and delivery logging, templating and campaigns — behind a startup check that will not boot without one.](https://software.engineer.company/portfolio/built-email-as-a-platform-capability-with-failover-62/) - [Delivered full Progressive Web App support — installable and offline‑capable — with Workbox runtime caching via next‑pwa.](https://software.engineer.company/portfolio/delivered-full-progressive-web-app-support-installable-and-74/) - [Planned and implemented new infrastructure functionality for internal and external systems, building solutions durable enough to still run years later with minimal change.](https://software.engineer.company/portfolio/planned-and-implemented-new-infrastructure-functionality-for-internal-85/) - [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://software.engineer.company/portfolio/built-a-layered-automated-test-suite-across-four-layers-94/) - [Moved slow work off the request path onto a River job queue — 15 worker modules, 8 scheduled tasks and 20 pg_cron jobs — so a request returns while the work behind it carries on.](https://software.engineer.company/portfolio/moved-slow-work-onto-a-river-job-queue-97/) - [Built first‑party error monitoring and OpenTelemetry tracing rather than buying them — payload sanitising, spike and regression detection, symbolication and a synthetic heartbeat — behind 11 operator views.](https://software.engineer.company/portfolio/built-first-party-error-monitoring-and-tracing-98/) - [Built fail‑closed abuse controls — 22 Redis‑backed rate limiters, Cloudflare Turnstile, request idempotency and an origin lock — so the platform sheds bots and floods instead of trusting its callers.](https://software.engineer.company/portfolio/built-fail-closed-abuse-controls-and-rate-limiting-100/) - [Ran the whole company on one 512 MB single‑core host — a git forge, a web server serving seven domains, Tor, two alternate‑protocol servers, backups and intrusion banning — by treating 464 MB of usable memory as the binding architectural constraint.](https://software.engineer.company/portfolio/ran-the-whole-company-on-one-512mb-host-109/) - [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://software.engineer.company/portfolio/held-the-generator-to-964-tests-and-a-coverage-floor-145/) - [Stopped an application filling memory at 41 MB a second — a recorded 111 GB of compressed pages on a 36 GB machine — by bounding every event stream, subscribing by event type and putting a rate budget on logging, taking 610,996 log lines down to 1,411.](https://software.engineer.company/portfolio/stopped-an-application-filling-memory-at-41mb-a-second-155/) - [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://software.engineer.company/portfolio/adopted-swift-6-strict-concurrency-over-a-c-event-loop-156/) - [Reached the half of the messaging core the application had never used — backup transfer, disappearing messages, message editing and resending, verified invitations, proxies and encryption policy — driving every test against the real library with no mocks.](https://software.engineer.company/portfolio/reached-the-unused-half-of-the-messaging-core-161/)