Your expertise: * Senior-level Android engineering experience with a strong command of Kotlin and Jetpack Compose * Solid understanding of modern app architecture, including MVVM / MVI * Experience with dependency injection using Hilt * Strong knowledge of Coroutines and Flow * Proven ability to own features end-to-end and successfully ship products to production * High level of autonomy and sound technical decision-making without close supervision
Will definitely be a plus: * Experience with real-time communication technologies: WebRTC, VoIP, voice / video * Experience with secure / encrypted messaging * Experience with WebSockets or push notifications * Familiarity with multi-device sync * Contributions to performance optimization, testing, or CI / CD processes * Startup or early-stage product experience
What’s in it for you? * Opportunity to deal with top-notch technologies and approaches in a world-leader product company with millions of customers * Opportunity to make a difference for online privacy, freedom of speech, and net neutrality * Decent market rate compensation depending on experience and skills * Developed corporate culture: no micromanagement, culture based on principles of truth, trust, and transparency * “You build it, you own it” mentality in most contexts * Support of personal and professional development * coverage of costs of external trainings, conferences, professional literature * support of experienced colleagues * in-house events and trainings * regular knowledge sharing in teams * English classes and speaking clubs * Life-balance support * truly flexible schedule, no time-tracking at all * 25 working days of vacation * 5 days of paid sick leave per month (if necessary) without providing a medical certificate * generous maternity / paternity leave program * Professionally strong environment, friendly and open atmosphere, ability to influence the product development and recognition for it
You will be involved into: * Building and owning features of the Thunderbolt Android app end-to-end — from design and implementation to release and maintenance * Taking responsibility for code quality, architecture, and the overall health of the Android codebase * Proactively proposing and driving improvements instead of waiting for direction * Collaborating closely with Backend, Web, and UX teams to ship a cohesive product
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 Software Engineer (Android) to join as a contractor and contribute to the development of the mobile 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.
As a Senior Software Engineer (Android) at Thunderbolt, you will take full ownership of the Android application end-to-end — from design and implementation through release and maintenance — while collaborating closely with Backend, Web, and UX teams to deliver a secure, scalable, and high-quality real-time communication product.
