# Sveinbjörn Geirsson Senior software engineer Reykjavík, Iceland sveinbjorn@sveinbjorn.dev https://sveinbjorn.dev/ https://github.com/Raudbjorn https://linkedin.com/in/sveinbjornG I build the systems behind the product, with an eye for reliability and how the next engineer will work with them. My background combines payment processing and pension systems with multi-tenant SaaS, cloud infrastructure, and search. ## Experience ### Massif Network Role: Senior Developer Dates: Aug 2025–present Location and media workspace for film production. Worked closely with the CTO/founder, driving backend and platform architecture. - Built PostgreSQL/PGMQ processing through a broker Worker using Hyperdrive, service bindings, and Durable Objects. Claim fencing rejects stale queue acknowledgments and finalization; bounded execution, retries, and dead-letter handling make failures visible. - Reworked test configuration and CI orchestration: a documented warm-cache comparison fell from 9m08s to 3m24s , with explicit test-environment separation. - Moved media storage from Supabase Storage to Cloudflare R2, with authenticated delivery and uploads. Unified web, admin, and Workers in a pnpm/Turborepo monorepo and built local integration tests connecting Wrangler Workers to Supabase. - Hardened tenant authorization, sharing permissions, and upload validation; migrated Worker authentication to Supabase JWKS. - Built tenant-scoped hybrid search with Meilisearch, Voyage AI embeddings, and index repair. Built an evaluation harness and graded golden set of 87 queries; compared per-photo vectors with one combined text-and-image vector per location, which performed better overall in this comparison; also tested keyword/vector weighting. - A separate 670-case A/B of Overture Maps enrichment detected no relevance gain (p = 0.75); recorded a recommendation against paid re-embedding. - Set up Grafana Cloud monitoring across the application, database, search, and Workers, connecting metrics and logs to dashboards and alerts. Cloudflare Workers / R2 / Wrangler · TypeScript · SvelteKit · PostgreSQL / Supabase · Meilisearch ### Reiknistofa Lífeyrissjóða Role: Software Engineer Dates: 2022–2025 - Developed and maintained IBM Informix pension systems for payments, collections and contribution statements; mortgages, bonds and securities; and disability, retirement and child-pension applications and other accrued benefits. - Integrated RL’s core systems with the Central Bank of Iceland’s reporting system in 2023–2024, including the mortgage-obligation register reporting each fund’s loan balances and arrears. Used personal access to the submission system to carry out the reporting. - Set up and operated an X-Road security server for queries from Tryggingastofnun and Sjúkratryggingar Íslands. Responses stated whether a member had applied for pension-fund rights and which rights the application concerned. IBM Informix · SQL · X-Road ### Korta / Rapyd Role: Software Developer Dates: 2013–2022 Joined Korta from university as its second developer; later helped newer developers navigate its payment systems. - Developed settlement and payment-distribution logic for fees, rolling reserves, refunds, payment splitting and withholding, and settlement-frequency rules across domestic and SEPA/SWIFT transfers. - Mapped Visa/Mastercard reconciliation and chargeback data to accounting codes across multiple currencies and cost/value dates, including when an accounting day could be closed. - Added logging and traceability to financial workflows and automated software releases. - Made core financial data available to frontend teams through IBM DB2 data services, without requiring them to know the underlying systems. Java · Scala · IBM DB2 · OAuth 2.0 ## Selected projects Independent work on developer tools, image processing, and local inference. ### Agent tooling & shared memory Built a coding-agent toolchain with Hindsight memory shared across two machines and claude-history, a Rust CLI for searching coding conversations. [github.com/Raudbjorn/claude-history](https://github.com/Raudbjorn/claude-history) ### pdq-wasm Built and published pdq-wasm to npm, providing WebAssembly (WASM) and TypeScript bindings for Meta’s PDQ perceptual image hashing in browser and Node.js applications. [www.npmjs.com/package/pdq-wasm](https://www.npmjs.com/package/pdq-wasm) [github.com/Raudbjorn/pdq-wasm](https://github.com/Raudbjorn/pdq-wasm) ### Fission & Intel Arc inference work Built a local inference runtime integration with supervised model serving, runtime identity checks, and cancellation. Maintained an Intel Arc-focused llama.cpp fork with SYCL performance work and reproducible correctness and benchmark checks. One recorded benchmark (PR #35) increased generation from 6.95 to 17.10 tokens/s at 16k context (Mistral-7B Q4_K_M, f16 KV cache, Arc A770). [github.com/Raudbjorn/ggml-llama.cpp](https://github.com/Raudbjorn/ggml-llama.cpp) ## Technical skills **Backend & data:** Multi-tenant SaaS, TypeScript, PostgreSQL, Supabase, SQL / RLS, PGMQ, OAuth 2.0, authentication and authorization. **Cloud & delivery:** Cloudflare Workers, R2, Wrangler, Hyperdrive, Durable Objects, KV; Docker, CI/CD, Vitest, Playwright, pgTAP, Grafana Cloud; staging/production configuration. **Search & AI:** Hybrid and vector search (Meilisearch), Voyage AI text/image embeddings, retrieval-augmented generation (RAG), retrieval evaluation, llama.cpp, local inference. **Languages & systems:** Rust, Go, Python, C++, SYCL, Java, Scala; SvelteKit / Svelte; IBM DB2 and IBM Informix in financial systems. **Spoken languages:** Icelandic and English. ## Education & recognition ### University of Iceland Dates: 2010–2013 BSc, Computer Science. Teaching assistant in undergraduate computer science courses. ### Voting-system security disclosure Dates: 2016 Identified and reported a CSRF vulnerability that could change a logged-in user’s vote. The maintainer acknowledged the report and fixed the affected election methods. ### Rapyd internal hackathon winner Dates: 2021 Part of the winning team building a working WhatsApp wallet proof of concept using the Rapyd Wallet and WhatsApp Business APIs. ### Accepted open-source contributions Contributed bounded shell-output capture to Oh My Pi and a public terminal-buffer renderer to Crepuscularity; both accepted upstream. [github.com/can1357/oh-my-pi/pull/789](https://github.com/can1357/oh-my-pi/pull/789) · [github.com/tschk/crepuscularity/pull/299](https://github.com/tschk/crepuscularity/pull/299) ## References ### Tómas Árni Jónsson Software Specialist · Deloitte Worked together on RL’s Central Bank reporting integration, 2023–2024. ### Þráinn Guðbjörnsson Chief Risk Officer · Festa Pension Fund Worked together on Korta’s early systems as two of its first developers, 2013–2017. Contact information available on request. ## Engineering work [sveinbjorn.dev/evidence.html](https://sveinbjorn.dev/evidence.html) [sveinbjorn.dev/evidence.md](https://sveinbjorn.dev/evidence.md)