Senior Full Stack Engineer
The Role
Tolken is a deeply technical team looking for a builder who craves complexity and ownership. You will work across the stack, from the core ledger to the user interface, ensuring systems are not just functional, but hyper-scalable, secure, and auditable. You will be hands-on in design, implementation, and deployment, collaborating closely with the founders to ship production-grade features in a high-velocity environment.
Key Responsibilities
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Design, build, and maintain end-to-end features across backend (ledger, routing services) and frontend (React-based UI).
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Implement and evolve production-grade APIs, data models, and integrations for a high-throughput financial system.
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Own the full lifecycle of features: design, implementation, testing, deployment, and ongoing reliability in production.
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Collaborate closely with the VP of Engineering, founders, and other engineers to translate product requirements into technical designs and delivery plans.
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Improve performance, scalability, and observability of the platform through profiling, tuning, and better monitoring.
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Contribute to engineering standards, code reviews, and technical decision-making in a fast-paced startup environment
Stack & Core Requirements
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5+ years building high-throughput, distributed backend systems; you understand the difference between “working” and “production-grade.”
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Strong backend experience in Python (FastAPI preferred), Go, or Java.
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Strong command of modern frontend stacks (e.g., React) and ability to build complex, data-dense interfaces.
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Deep understanding of modern database design; depth in Postgres and Redis is a strong plus.
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Hands-on experience with cloud-native environments (GCP preferred), containers, and Kubernetes.
System Architecture & Practices
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Mastery of distributed systems concepts: microservices, idempotency, retry/backoff strategies, and eventual consistency.
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Experience with event-driven architectures and high-volume queues (e.g., Kafka, Redis Streams) and caching layers.
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You build with observability in mind: metrics, tracing, and logging, and are comfortable working with modern monitoring stacks.
Requirements
Essential:
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5+ years of experience as a full stack or backend-heavy engineer working on production systems.
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Strong proficiency in at least one of: Python (FastAPI preferred), Go, or Java, including building and operating APIs.
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Solid experience with modern frontend frameworks (e.g., React), comfortable building complex, data-dense interfaces.
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Strong experience with relational databases and caches; depth in Postgres and Redis is highly valued.
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Hands-on experience with cloud-native infrastructure (GCP preferred), Docker, and Kubernetes.
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Solid understanding of distributed systems, event-driven architectures, and designing for reliability and scalability.
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Comfortable operating in a low-structure, high-ambiguity startup environment with a high degree of ownership.
Desirable:
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Web3 & privacy: experience with Ethereum/L2s, smart contracts, and especially zero-knowledge proofs (zkSNARKs) for privacy-preserving audit trails.
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AI/ML: experience with graph-based models, fraud detection, or anomaly detection on live transaction streams.
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Fintech DNA: background in payments, treasury, or other high-audit, regulated environments.
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Prior early-stage startup experience and familiarity with rapid iteration and continuous delivery.
Who You Are
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First-Principles Thinker: You don't just use tools; you understand why they work. You can reason from the ground up to solve novel problems in hybrid (Fiat/Crypto) finance.
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High Velocity: You move extremely fast and thrive in high-ambiguity environments. You ship to learn.
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Low Ego, High Output: You care about the product, not the pedigree. You are comfortable switching contexts rapidly—debugging a race condition one hour and designing a new API the next.
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Owner Mindset: You don't wai