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 payment / identity platforms like Stripe .

Frontend Proficiency : Solid experience developing mobile applications using React Native and the Expo framework, with a deep understanding of component lifecycle, hooks, and performance best practices.

State Management : Experience with a modern state management library (or similar patterns like Redux / MobX / Context) and implementing a clear, modular frontend architecture.

Testing & CI / CD : Proficient with unit and integration testing frameworks ( JUnit, Mockito, Testcontainers ) and familiarity with continuous integration tools ( GitHub Actions, Gradle ).

Development Principles : Strong grasp of software design patterns, RESTful API design ( OpenAPI / Swagger ), and adhering to strict code style and quality standards.

Curiosity + willingness to learn new stacks quickly.

Preferred Kotlin DSL / Gradle : Familiarity with Gradle for build management, especially using the Kotlin DSL .

Testcontainers : Direct experience utilizing Testcontainers for local, reliable integration testing against real services / emulators (e.g., Firestore Emulator).

Microservice Architecture : Experience working within a microservices environment and understanding concepts like service discovery, configuration management, and distributed tracing.

Mobile Build Process : Experience managing different build variants ( Development / Production Debug / Release ) and understanding the Expo bare workflow with config plugins.

Security Deep Dive : Experience implementing advanced security features like API rate limiting, robust input validation, and secure handling of webhook signatures.

Cross-Platform UI / UX : A keen eye for mobile UI / UX and experience building a reusable design system or component library. What You'll Do

Backend Development : Design and maintain scalable Java 21 Spring Boot 3.x microservices.

Data Persistence : Implement secure data models and CRUD using Google Cloud Firestore (NoSQL).

API Integration : Integrate complex third-party APIs like Firebase Admin SDK and Stripe Java SDK (Identity Verification, webhooks).

Mobile Feature Development : Build cross-platform user features for mobile using React Native (Expo) within a modular architecture.

Frontend State & UI : Manage application state, define data models, custom hooks, and build UI components based on the design system.

Quality & CI / CD : Write unit / integration tests (JUnit 5, Testcontainers with Firestore Emulator) and enforce code quality (Spotless, ESLint) via GitHub Actions.

Security : Secure all API endpoints using Firebase ID token filters, enforce UID matching, and handle sensitive data securely.

Collaboration : Work with founders, participate in code reviews, and optimize services for performance.

Why join us? Founding team mindset → This is not just another contract gig. You’ll be building alongside the founders and early hires, shaping how Toka works from the ground up.

Contract-first, core intent → We start flexible, but the goal is clear : grow into the founding engineering team. Equity and long-term ownership are on the table if it’s the right fit.

Collaboration at the core → We believe the best work comes from tight collaboration — async-first, transparent, and with everyone thinking like an owner.

Impact that matters → Resale furniture is a $50B+ vertical waiting to be reinvented. Your work will directly reduce waste and carbon emissions at scale.