React Software Engineer
ThunesSão Paulo, São Paulo, BrazilPosted 7 April 2026
Tech Stack
Job Description
About the Role
We're looking for a frontend engineer to join a small, senior team building the payment platform that powers financial operations for virtual world publishers. You'll own frontend work across multiple codebases — an internal admin tool, embeddable payment widgets, and publisher-hosted transaction pages — all securely handling real money, real compliance requirements, and real users.
This isn't a "build marketing pages" gig. You'll be working with GraphQL APIs backed by Go microservices, writing code that touches invoicing, payouts, KYC verification, and fraud detection. The work matters and the stakes are real.
What You'll Work On
Admin Tools (React, Vite, Chakra UI, Apollo Client): Internal tooling used by operations teams to manage accounts, transactions, and payment methods. Turborepo monorepo with a GraphQL BFF layer.
Payment Widgets (Next.js, React, Tailwind CSS, Server Components): Embeddable checkout, payout, and KYC flows where every millisecond of load time impacts conversion. Active rewrite with a performance-first architecture.
Publisher-Hosted Pages (Next.js, Chakra UI, SSR): Multi-tenant, themeable transaction pages served under publisher-branded domains with CNAME routing and per-publisher customization.
Day-to-Day
Ship features and fixes across multiple TypeScript/React codebases.
Write and maintain unit tests (Vitest + React Testing Library) and help with Playwright e2e tests (Python/pytest).
Work with a GraphQL API layer that translates between the frontend and Go microservices (accounts, payments, invoicing, wallets).
Run the full local stack via Docker Compose (makeworld) with hot-reload - no waiting for builds.
Maintain or improve test coverage.
Collaborate on a small team where you'll have real ownership and influence over frontend architecture.
You Should Have
React applications - you've shipped features that real users depend on.
TypeScript proficiency .
Testing discipline - experience with Vitest or Jest and React Testing Library or similar.
Component library experience - you've worked with Chakra UI, MUI, or similar design systems and can extend them without fighting them.
Linux shell proficiency - comfort navigating the file system, using common utilities, and basic scripting.
Bonus Points
Experience with payment/fintech UIs - checkout flows, KYC, compliance screens.
Familiarity with Playwright or similar e2e frameworks.
Docker comfort - you don't panic when the local stack is containerized.
Python literacy. Enough to read and write Playwright test scripts.
Go literacy. Enough to read the backend services and understand the APIs you will be calling.
GraphQL experience - you've worked with Apollo Client or a similar GraphQL client and understand queries, mutations, caching, and schema design.
Experience building UIs for role-based access control (RBAC) or complex permission systems.
You've worked on multi-tenant/white-label products with theming systems.
Experience working in monorepos (Turborepo, Nx, or similar).
What We're NOT Looking For
Someone who needs a design system handed to them pixel-perfect - you'll make pragmatic UI decisions in lieu of hi fidelity mockups.
A "framework tourist" chasing the latest meta-framework - we need someone who ships, not someone who rewrites.
Someone uncomfortable with legacy code - parts of the codebase are being actively migrated and you'll need to work in both old and new patterns gracefully.
Why This Role
Small team, big impact - you won't be pixel-pushing in a feature factory. You'll shape frontend architecture across multiple products.
Real domain complexity - payments, compliance, multi-currency, fraud detection. The problems are genuinely interesting.
Modern stack, active migration - you get to help move things forward rather than maintain a frozen codebase.
Strong engineering culture - enforced coverage thresholds, pre-commit hooks, CI gates, deployment on merge. The team cares about quality an ... (truncated, view full listing at source)
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