Hybrid Engineer (Mobile & Backend)

Location : Remote (preferred India-based)Type : Contract (with potential to join founding team full-time + equity)Toka is on a mission to make secondhand, first choice.We’re building the world’s first AI-native resale platform for furniture and home goods. Imagine if buying secondhand felt as smooth, beautiful, and reliable as buying new. We’re aiming to be the amazon of resale.We’ve locked in design + product direction, and now we’re expanding our team with a Full stack engineer to help us ship fast, test bold ideas, and join Toka's world class engineering team.What you’ll do Develop Core Backend Services : Design, develop, and maintain production-ready Java 21 microservices using Spring Boot 3.x (Web, Security, Validation) for high-performance and scalable application functionality.Implement Cloud Persistence : Engineer efficient and secure data models and CRUD operations utilizing Google Cloud Firestore as the primary NoSQL data store.Integrate Third-Party APIs : Implement complex integrations, focusing on Firebase Admin SDK for authentication / security and the Stripe Java SDK for critical flows like Identity Verification and secure webhook processing.Build Cross-Platform Features : Develop new user-facing features for our mobile application using React Native (Expo), adhering to a modular, layered architecture with distinct feature modules.Manage Application State & UI : Implement robust state management in the frontend, defining data models, custom hooks, and UI screens / components within the design system and feature modules.Ensure Code Quality & CI / CD : Write comprehensive unit and integration tests (JUnit 5, Mockito, Testcontainers with Firestore Emulator) and maintain code quality standards (Spotless, ESLint, Prettier) enforced via GitHub Actions CI pipelines.Maintain Security Posture : Ensure all API endpoints are secured using the custom Firebase ID token filter, enforce Token UID match, and handle sensitive data / webhook signatures securely.Collaborate & Optimize : Work closely with (ex-Atlassian) founders to turn product direction into working software, participating in code reviews and optimizing services for performance and reliability.Must-have (4+ Years Experience) Backend Expertise : Strong proficiency in Java 21+ and extensive experience developing robust, scalable APIs with Spring Boot 3.x and the Spring ecosystem (Security, Web, Data).Cloud Persistence : Hands-on experience with Google Cloud Firestore or other NoSQL databases, including indexing and query optimization.API Integration & Security : Proven ability to integrate and secure external services, particularly Firebase Authentication and / or complex