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# Backend Staff Engineer

- **Company:** Koinly
- **Location:** London, UK (Remote available)
- **Experience:** Expert
- **Salary:** £80,000.0 - £100,000.0
- **Contract:** Permanent contract
- **Skills:** Application Programming Interfaces (APIs), Artificial Intelligence, JIRA, Unit Testing, Software Quality, Data Transformation, Cursor (Graphical User Interface Elements), Software Design Patterns, Distributed Systems, Github, PostgreSQL, Node.Js, Parsing, Query Optimization, Blockchain, Ruby, Standard Sql, Simple Data Format, Systems Integration, TypeScript, System Availability, Backend, Heroku, Core Data, Sentry, JestJS, Data Pipelines
- **Published:** August 4, 2026
- **Apply:** https://uk.indeed.com/viewjob?jk=69859cfe691af71f

## About the Role

We're looking for someone who thrives on complex, business-critical financial systems - architectural depth, high throughput, high-volume ETL, and high stakes. You'll focus on optimising, refactoring, and elevating our backend architecture while ensuring deterministic execution, high availability, and financial-grade correctness.

Above all, we value a high sense of product ownership, exceptional code quality, autonomy, and openness: you take responsibility for outcomes, not just tasks, and you work independently while staying transparent and collaborative., * Real, production-level DeFi experience - AMMs, lending, staking, LP positions, and bridges. You understand what on-chain activity actually means, and you can spot data anomalies instantly.

 * Advanced data modeling and SQL skills, with a track record of tuning performance on massive PostgreSQL datasets.
 * Proven professional experience with Rust - you've used it in production or professional settings, can read and write it confidently, and are ready to work in it where extreme performance demands it.
 * Fluency with the latest AI development tools such as Claude/Codex/Cursor, and the judgment to put new tools to work effectively in a professional workflow., * Public portfolio of projects available on GitHub or similar platforms.
 * Deeper Rust experience, especially in performance-critical data processing.
 * Background in financial products, double-entry accounting, or tax domains.
 * Familiarity with Ruby (our services interoperate with a Ruby codebase).
 * Knows and understands our product., * Expert-level TypeScript. You should reach for strong typing instinctively, not as an afterthought. We deal with complex financial data where "mostly correct" isn't good enough; your TS skills should reflect that.
 * Deep Distributed Systems & DeFi context. This is a Staff-level role. You need a deep understanding of async queue architectures, idempotency, and how smart contracts execute on-chain. We need someone who can hit the ground running with a complex, high-throughput pipeline.

## Description

* Work closely with product and engineering leads, serving as a key technical partner to evaluate ideas, propose architectural solutions, and take real ownership of our backend data pipeline., * TypeScript (strict, modern) on the Bun runtime, with modern TS tooling (oxlint, Biome)
 * Distributed processing with RabbitMQ and Redis (ioredis)
 * PostgreSQL - schema design, query optimization, and migrations at scale
 * Vitest for unit and integration testing
 * Sentry for error monitoring

Data & Blockchain

 * Blockchain libraries and node/indexer APIs; RPC and provider reliability patterns
 * On-chain data decoding: ABIs, event logs, traces, token standards, transaction semantics
 * Data parsing and wrangling: csv-parse, xlsx (SheetJS), node-html-parser
 * Integrations against messy, inconsistent third-party APIs and file formats

Infrastructure & Tooling

 * PostgreSQL, Heroku, GitHub, JIRA, * Direct impact: Our users rely on Koinly for their financial compliance. Every performance optimization and reconciliation engine improvement you ship directly reduces the stress of hundreds of thousands of investors.
 * True ownership: We don't believe in "ticket-flipping." You'll own core data services from architecture through deployment and scaling. You have the autonomy to make system decisions that stick.
 * High-signal, low-noise: We're remote-first and async-first. We don't do unnecessary meetings or processes for the sake of process. You'll have long blocks of deep work time to actually build.

Come and shape the future of crypto tax with us

We aren't just building a calculator; we're building a platform that empowers crypto investors to make the best decisions for their financial future. If you're ready to own a piece of that journey and build a product people actually need, we want to hear from you.


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