Diana Bârsan

Principal engineer with 17+ years of experience, nearly 9 at Medic. There I architected and owned four iterations (2018–2026) of the data replication behind the open-source Community Health Toolkit (CHT), which keeps health workers' phones working without internet, as single deployments grew from a few hundred to 20,000 users. The platform serves 200,000+ community health workers (CHWs) in seven countries. #1 contributor since 2018 to its public codebase: github.com/medic/cht-core. Deep expertise in performance, scalability, and distributed data. Fully remote since 2009.

Experience

Principal Software Engineer — Medic (formerly Medic Mobile) · Remote

Jan 2022 – Sep 2026

Rearchitected data replication with a custom endpoint in place of CouchDB's built-in protocol (2023), cutting replication time by 90%; added monitoring with failure tracking
Migrated replication queries to a faster search engine (2025), shaving a further 60% off replication time and 50% off system load in production; together, single deployments scaled from a few hundred to 20,000 active users
Built a pipeline archiving stale records to cold storage, reducing median replication time from 2.8 minutes to 6 seconds and 1-hour timeouts to 3 minutes in one production deployment; admins adopted it the next day
Set the technical direction for a team of about six and defined the long-term platform strategy; ran several open-source squads of outside contributors and mentored 10 of them, some still contributing today
Unblocked a year-stalled analytics-pipeline replacement in 3 weeks by swapping an unmaintained, data-loss-prone stage for a custom connector; now runs analytics for every deployment
Led a year-long, LLM-informed UX overhaul of health workers' task workflow (offline prioritization, search, filters, GPS capture): partners reported 30% higher task completion six months after release
Engineered automated performance benchmarks (EC2, database endpoints, frontend) that gate every release: caught a 20x indexing slowdown in an upstream database release, which I reported and upgraded after the fix; also measured the replication gains above
Cut server load in deployments with aggressive data purging: a caching layer for retention checks removed redundant requests that took up to 40% of server time
Architected the move from a monolith to Docker services with one-click, zero-downtime upgrades; Docker by default for teams without ops staff, Helm charts for Kubernetes where scale demanded it
Fixed a contractually required audit trail for healthcare deployments: replaced truncated proxy request logs with an audit database recording every document change, its user, and request ID

Software Engineer — Medic Mobile · Remote

Jan 2018 – Dec 2021

Rewrote the CHT's replication engine (2018), the foundation of the platform's offline-first replication; previously, users with too many documents could crash the server
Introduced per-record access control, closing a gap where users had near-unrestricted API access: limited users to the app's own endpoints and enforced permissions on every write
Implemented server-side data-retention controls (2019) and configurable limits on how much data each user downloads, making the app usable for users overseeing many health workers, who had abandoned it as too slow
Drove the full rewrite of the web client from AngularJS to Angular 10; fixed a 2–3x page-load slowdown, caused by the framework re-checking the page on every background data operation, before release
Integrated SMS/messaging gateways and added token login: users get an SMS link that signs them in, replacing plain-text credentials circulating in spreadsheets
First responder for production incidents and live deployments; stopped an SMS auto-reply loop that caused an outage in a telecom's network in Nepal, by adding loop detection

Full Stack Web Developer — Novisites VOF · Netherlands

Aug 2012 – Aug 2017

Developed and maintained custom web applications and Prestashop webshops that ran in production for years: integrated Amazon, payment processors (PayPal, Klarna) and shipping platforms; engineered a shared cart across a platform's separate webshops; took over a popular legacy shop (~1 order every 2 minutes) generating personalised printable PDF gifts

Summary

Experience

Open Source & Community

Technical Skills

Languages

Education