Sveinbjörn
Geirsson

Senior software engineer

Reykjavík, Iceland

sveinbjorn@sveinbjorn.dev

github.com/Raudbjornlinkedin.com/in/sveinbjornG
Download CV PDF · 2 pages sveinbjorn.dev · github.com/Raudbjorn

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

Aug 2025–present

Platform & search

Massif Network

Senior Developer

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.
Durable processing path A row created in PostgreSQL is dispatched through its work queue (PGMQ) to a broker Worker that leases and retries work with bounded reads, then calls domain Workers over service bindings for metadata, embeddings, search repair and geocoding. Work that exhausts its retries goes to a dead-letter queue. PostgreSQL row created PGMQ work queue broker Worker lease · retrybounded reads domain Workers metadata · embeddingssearch repair · geocoding service bindings retries exhausted dead letter
  1. PostgreSQLRow created
  2. PGMQWork queue
  3. Broker WorkerLease · retry · bounded reads

    Retries exhausted: work goes to the dead-letter queue.

  4. Domain WorkersVia service bindings for metadata, embeddings, search repair, and geocoding.
Durable processing path at Massif: work created in the database survives the trip to the edge, or lands somewhere visible when it doesn’t.

Cloudflare Workers / R2 / Wrangler · TypeScript · SvelteKit · PostgreSQL / Supabase · Meilisearch

2022–2025

Pension systems

Reiknistofa Lífeyrissjóða

Software Engineer

  • 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

2013–2022

Payments & settlement

Korta / Rapyd

Software Developer

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 infrastructure

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

Local inference

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

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

2010–2013

University of Iceland

BSc, Computer Science. Teaching assistant in undergraduate computer science courses.

2016

Voting-system security disclosure

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.

2021

Rapyd internal hackathon winner

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 · 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.