johannaslund

Solo developing a tickless, event-driven, 4D multiplayer game engine in Rust supporting thousands of concurrent players in infinite procedurally generated worlds. Authored and open sourced contime: a lock-free, multi-worker, in-memory, continuous-time reconciliation engine for unreliable event streams. Authored and open sourced minbin: a tiny (~500 LOC), zero-dependency, safe, no-std binary serializer prioritizing predictability and auditability.

As Founding CTO, I launched Esper, a Shopify App AI Agent for natural-language data querying and ingestion delivering e-commerce insights for merchants. Selected for the J-StarX Silicon Valley Extended program in Japan (500 Global/JETRO).

Reporting directly to the CTO, I was responsible for maintenance and delivery of major projects on the product roadmap in an enterprise-grade, SOC 2 certified environment. Delivered a secure customer-facing API and integrations framework, complete with rate limiting, API keys, SAML support, and support for pure-Python function endpoints. Transitioned our site analytics ETL processing from a third party to an in-house solution, halving expenses and improving visitor insights for customers and sales. Provided emergency support for multiple high level incidents according to Service Level Agreements, produced postmortems and managed disaster recovery procedures. Hired, mentored and managed 2 engineers.

Freelanced in Japan and built a serverless backend in Go for a Silicon Valley startup.

Reporting directly to the CEO, I led the rebuild of a crowdsourcing accounting platform for a Japanese startup, supporting zero-error accounting journal exports.

Reporting directly to the CEO, I led the rebuild of a CRM and online directory service driving $3M ARR and managed the service, all software, infrastructure and hardware.