Back Home

Janek Rahrt

Staff Engineer·Product Engineering · Crypto · Open Source

Remote, based in Germany

hello@rahrt.merahrt.megithub.com/janek26x.com/0xjanek
Product-minded engineer with 8+ years shipping user-facing products and developer infrastructure end-to-end. Built Argent X from scratch to 300,000+ Chrome users and developed and lead starknet.js to ~115K weekly downloads. Contributor to Next.js and viem. Bootstrapped Vesu to $50M+ TVL as founding engineer and previously shipped at 7M+ MAU scale at Joyn. Strong in TypeScript, systems thinking, and 0-to-1 execution across AI-native workflows, enterprise-grade quality, and protocol-heavy environments.
Experience

Rainbow

Staff Engineer

Jul 2025 - Present

  • Revived the Rainbow browser extension after an extended period without an active maintainer — modernized the codebase and restored shipping velocity on one of the most-used Ethereum wallet extensions
  • Shipped EIP-7702 support — the upgrade that lets standard Ethereum wallets temporarily act as smart accounts, unlocking batched transactions, gas sponsorship, and session keys without forcing users to migrate accounts
  • Shipped EIP-5792 support — the dApp-to-wallet capability standard that collapses multi-step flows (*approve + swap*, *mint + stake*) into a single confirmation, a major UX shift for the wider ecosystem
  • Owning the extension's transaction pipeline end-to-end: dApp connector APIs, signing infrastructure, and product UX across the wallet surface

Argent (Ready X)

Senior Engineer · Lead Engineer

Aug 2021 - Jul 2025

  • Built Argent X from zero to 300,000+ Chrome users with 5.0 stars across 89,500 ratings
  • Owned full-stack delivery: React/TypeScript extension UI, background service workers, dApp connector APIs, and transaction pipelines
  • Co-developed starknet.js as core contributor; authored major v3 architecture and modernization work; ~115K weekly downloads
  • Authored the wallet connection standards and built @argent/get-starknet (~8,200 weekly downloads)

Vesu.xyz

Founding Engineervia Argent Incubator

2024

  • Bootstrapped the full product from zero: lending/borrowing flows, real-time position tracking, and risk dashboards
  • Scaled protocol usage to $50M+ TVL, becoming the largest lending protocol on Starknet

Joyn

Software Engineer

Sep 2019 - Jul 2021

  • Built payment and user-management systems for the ProSiebenSat.1 / Discovery streaming JV
  • Shipped production software at 7M+ monthly active users and 10M+ app downloads
Open Source

starknet.js

1,300 stars · 115K dl/wk

Core contributor and v3 architecture author for Starknet JS

Argent X

638 stars

First Starknet browser wallet, built and scaled end-to-end

get-starknet

8,234 dl/wk

Ecosystem-standard dApp to wallet integration SDK

Next.js

134K+ stars

Contributor to Vercel's flagship React framework

viem

3,400+ stars

Contributor to a leading TypeScript Ethereum library

trpc-browser

47 stars

Type-safe RPC over extension message channels

Skills

Engineering Core

TypeScript - React - Next.js - Node.js - API design - product architecture

Infrastructure

PostgreSQL - WebSockets - REST - GraphQL - CI/CD - monitoring

Protocol / Web3

Ethereum - Starknet - JSON-RPC - account abstraction - smart wallet patterns

AI-Native Delivery

Cursor - Claude Code - custom automation harnesses - rapid iteration loops

Leadership Style

high ownership - cross-functional collaboration - developer empathy

Speaking

Building Web3 Tools That Matter

StarknetCC - Paris - 2023

Web3 for Mass Adoption with Starknet and React Native

App.js Conf - Europe - 2022 - Co-presented with Sean Han

Education

Self-taught engineer

CS College dropout

Continuous learning through OSS, conferences, and production shipping

More

Led audit coordination with top-tier audit firms in the past

Won $10,000+ hackathon prizes (Ankh · DoraHacks)