Senior Full-Stack Engineer (Frontend-Focused, AI-First)

October 21, 2026

Remote

Senior

Also worth knowing

English is required
GitHub profile required
Crypto or web3 project

Description

A fintech product company building stablecoin payment infrastructure is hiring a senior full-stack engineer to own the frontend of its payment products, with roughly 70% frontend and 30% backend work. The team builds crypto on/off-ramp widgets, merchant checkout pages and back-office admin apps, and works agent-first — planning, writing, testing and reviewing code with AI agents. The stack is React 18/19 with TypeScript on the frontend and Java/Spring Boot, Kotlin and Node.js services on the backend, running on Kubernetes. Work is fully remote in an international team with a weekly release cycle.

Responsibilities

Own features from ticket to production: UI, API contract, backend change, tests, release and monitoring
Make frontend architecture decisions and drive ongoing migrations from the legacy admin to a new admin and from older UI libraries to the modern stack
Introduce stricter type checks and improve frontend performance across payment products
Build and improve AI-driven development workflows: project context files, shared skills and commands, automated PR review in CI, agent-driven end-to-end and visual checks
Review code of teammates and agents and keep the quality bar high
Work with product, design in Figma, QA and backend engineers inside a weekly release cycle
Develop the crypto on/off-ramp widget: embeddable buy/sell flow with KYC, card payments with 3-D Secure, alternative payment methods and a customer account area in one codebase for multiple white-label brands
Build merchant checkout hosted payment pages, from a simple one-step checkout to a full multi-step flow with KYC and compliance screens
Support back-office admin apps used daily by operations, compliance and support
Implement backend changes: API endpoints and business logic in Java/Spring Boot services

Requirements

5+ years of commercial frontend development
3+ years with React + TypeScript in production
Solid modern React: server-state management with TanStack Query or similar, client state via Zustand/Redux, forms, routing, performance
Comfortable working with large legacy codebases, not only greenfield projects
Production backend experience in at least one language; Java or Kotlin with Spring is a plus, Node.js/TypeScript or Go are fine
Ability to design a REST API, work with PostgreSQL (schema, indexes, migrations) and ship changes in existing Java services
Agentic development as the daily way of working with Claude Code, Codex or a similar agent, not just autocomplete
Keeping project context files and connecting agents to real tools through MCP: issue tracker, GitHub, Figma, databases, browser
Working in a plan → implement → verify loop where the agent proves its work with tests, type checks and browser automation
Running agents in parallel and headless, for example an AI review bot in CI
Reviewing agent output critically and knowing its failure modes: invented APIs, silent scope creep, fixing a test instead of the code, leaked secrets, prompt injection
Tracking changes in agentic tooling (new features, models, practices) and bringing what works into the workflow
Testing: Playwright for end-to-end, Vitest or Jest for unit and integration tests
Security-minded mindset: real money, personal data, auth tokens, iframes and cross-origin messaging
Fluent Russian, the team's working language
English good enough to read and write technical texts: tasks, pull requests and docs are in English

Conditions

Fully remote work in an international team
Roughly 70% frontend and 30% backend split in the role
Weekly release cycle together with product, design, QA and backend engineers
The company pays for AI tooling
Competitive salary based on individual performance review
Transparent feedback culture that values ownership and visible impact
AI code review runs on pull requests in CI and only advises, humans decide
Recruitment process: CV application, application review, HR interview with a short technical screen, technical interview and final interview with the CTO