// jorge jimenez — backend engineer
I build backend systems for moving money.
Backend engineer with 5+ years at Bitrefill — the world's largest crypto-only e-commerce platform — building payment infrastructure, multi-blockchain settlement, and APIs that stay up.
5+ years · 100k+ requests/day · millions of EUR in weekly volume
// experience
Bitrefill
Jun 2020 – Aug 2025
Backend Engineer · Remote (Sweden) · promoted from intern
- Led backend development of a crypto-funded Visa debit card with a licensed third-party card issuer (KYC/AML onboarding, fraud controls, issuer integration), taking it from design through EU/EEA-wide launch and its first year of production growth.
- Designed a fault-tolerant payment-detection engine (Node.js/TypeScript) that monitors and settles cryptocurrency payments across 8+ blockchains concurrently, cutting median detection-to-settlement time from ~8s to ~4s versus the previous sequential pipeline.
- Redesigned two core payment-method flows on a high-traffic storefront with zero downtime, lifting checkout conversion by ~6% and cutting p95 payment-API latency from 700ms to 250ms.
- Hardened critical payment services against replay and double-spend by enforcing idempotency and strict input validation, and raised their automated test coverage from 45% to 85% (Jest, Mocha).
- Carried on-call for production payment infrastructure, triaging incidents across blockchain nodes, card systems, and vendor integrations backed by monitoring and alerting.
- Migrated legacy data stores to MongoDB with redesigned schemas and indexing, cutting p95 query latency from 1.2s to 50ms on hot read paths.
- Designed and built integrations with gift-card vendor APIs (REST & SOAP), processing 100k+ requests/day and millions of EUR in weekly volume.
// projects
Syntony · TypeScript, gRPC
Distributed data store built on CRDTs for conflict-free replication, with a SWIM-style gossip protocol over gRPC for membership and failure detection.
Tieout · TypeScript
Open-source payments-reconciliation engine that ingests transaction records from ledgers, payment processors, banks, and stablecoin rails, matches them across sources, and records every run in an immutable audit log. Live demo
Airclip · Go
Cross-platform clipboard that brings Apple's iPhone-to-Mac universal copy-paste to any platform.
// stack
languagesTypeScript · Node.js · Go · Rust · Python
backendREST & SOAP APIs · gRPC · microservices · distributed systems · message queues (BullMQ)
paymentsidempotency · settlement & reconciliation · card issuing (KYC/AML, fraud controls)
dataSQL (PostgreSQL) · NoSQL (MongoDB, Redis/Valkey) · Drizzle ORM · schema design · query optimization
testingTDD · unit & integration testing · Jest · Mocha
frameworksExpress.js · Hono · Gin · Next.js · React
devopsDocker · Linux · AWS · CI/CD (GitHub Actions, Jenkins) · monitoring & alerting · incident response
// education
B.S. Computer Science
May 2026
A.A. Computer Science
Dec 2024