Back End Engineer

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’re now we’re expanding our team with a mid level back end engineer to help us ship fast, test bold ideas, and join Toka's world class engineering team.What you’ll doDevelop 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.Develop REST APIs for Mobile Client: Design, implement, and optimize robust, secure, and scalable RESTful APIs to support all features of the mobile application.Ensure Code Quality & CI/CD: Write comprehensive unit and integration tests (JUnit 5, Mockito, Testcontainers with Firestore Emulator) and maintain code quality standards (Spotless) 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, 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.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.PreferredKotlin 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.Security Deep Dive: Experience implementing advanced security features like API rate limiting, robust input validation, and secure handling of webhook signatures.Cloud Deployment/Infrastructure: Experience with deploying and monitoring services on Google Cloud or equivalent.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.Let’s build the future of resale. 🌍