Location: Remote
Your expertise:
3+ years of experience with TypeScript (strict types, generics, discriminated unions)
Strong frontend expertise: React 18 (hooks, suspense, SSR / hydration, code-splitting), MobX 6, React Router v5, SCSS, react-hook-form, Webpack 5
Solid backend expertise with Node.js 20.x
Experience with Express 4, InversifyJS (dependency injection), TypeORM with PostgreSQL (entities, migrations, transactions)
Experience with server-side rendering and WebSockets
Proven ability to own features end-to-end and deliver to production
Strong sense of ownership and accountability
Strong problem-solving and architectural thinking skills
Ability to make sound technical decisions independently, without close supervision
Good communication skills in English — Upper-Intermediate (B2) or higher
Will definitely be a plus:
Experience with LiveKit (livekit-client, livekit / components-react) or equivalent WebRTC (rooms, tracks, signaling)
Understanding of media transfer, chunked uploads / downloads, and S3-style object storage flows
Experience with performance optimization, testing, or CI / CD pipelines
Prior startup or early-stage product experience
What’s in it for you?
Vacation / sick leave policy: 30 days of paid time off and 5 sick days per year; no separate public holidays
Equipment policy: Equipment is provided by the company
Compensation review policy: On demand
Performance review / salary review: Performance review every quarter
You will be involved into:
As a Senior Software Engineer on the Web team working in a hybrid Agile environment, your responsibilities include:
Building and owning features of the Thunderbolt web app end-to-end — frontend, SSR, and backend services — from design and implementation through release and maintenance
Taking responsibility for code quality, architecture, and the overall health of the web codebase
Writing code, creating tests, conducting code reviews, and designing technical solutions
Proactively proposing and driving improvements rather than waiting for direction
Collaborating closely with Mobile, Backend, and UX teams to ship a cohesive product
Applying best practices of SOLID principles and CI/CD-based development workflows
Participating in all product evolution processes in a fast-moving startup environment
About the company and project:
ZONE3000 is a 2400+ people family that forms a new cultural code in the software development business. For 25 years we have been focusing on the highest quality of projects and empowering people to think big and make a difference. We are looking for talents who want to create and improve technological solutions for tomorrow and make things as best possible.
On behalf of our client Thunderbolt LLC (thunderbolt.com) — a next-generation business communication platform that combines secure, domain-based messaging with AI-powered automation to help businesses communicate with their clients smarter and safer, ZONE3000 is looking for a Senior Software Engineer (Web) to join as a contractor and take full ownership of the web product.
Thunderbolt LLC is a US-headquartered startup built around Thunderbolt — a secure business communication platform. The product enables voice and video calls and chat messaging using a company’s domain name instead of a phone number or email, with end-to-end encryption, domain-ownership verification, and DNSSEC protection.
Thunderbolt combines secure, domain-based communication with AI-powered automation, giving businesses a unified platform to manage client conversations across their website and beyond.
The team is organized across four core functions — Mobile, Web, Backend, and UX — and collaborates closely to evolve the product from a domain-based communication tool into a full AI-powered business communication platform.
