Level

Fireblocks

Full Stack Engineer, Blockchain

Fireblocks is hiring a Full Stack Engineer, Blockchain in London, United Kingdom. Level rates it ; you can apply on Fireblocks.

Level's read on this job

  • On Level's scale, this software engineer role is Little AI ●○○○: aI is not part of the work.
  • The posting mentions blockchain, defi and backend among its tools and skills.
  • Level classes it as a senior role.
  • Fireblocks has 26 other open roles on Level.

AI in this role

Full Stack Blockchain Engineer designing and building scalable backend services and multi-chain financial infrastructure.

blockchaindefibackendsmart-contractsapi

Fireblocks is the company bringing global finance onchain. Backed by over $1 billion in capital, we are the premier digital asset infrastructure provider trusted by thousands of industry-defining financial institutions, including banks, payment providers, fintechs, and global corporates such as BNY Mellon, BNP Paribas, ANZ Bank, Western Union, Stripe, and Revolut. Built for institutional scale and security, our enterprise-grade platform and network have powered over $14 trillion in digital asset transfers worldwide.

About Fireblocks

Fireblocks is on a mission to enable every business to easily and securely access digital assets and cryptocurrencies. As a leading provider in the digital asset space, we are committed to fostering a diverse and inclusive workforce that mirrors the global clientele we serve.

About the Team

The FinApps Access team at Fireblocks builds the backbone of on-chain access for some of the world's largest financial institutions and crypto-native organizations. We operate at the intersection of blockchain protocol engineering and enterprise-grade reliability — designing systems that route, protect, and optimize transactions across dozens of chains at scale.

You'll work on mission-critical infrastructure powering DeFi connectivity, multi-chain integrations, transaction execution pipelines, and on-chain data access — with direct impact on how billions of dollars flow through decentralized networks every day.

What You'll Do

  • Design and build robust, scalable backend services supporting high-volume on-chain transaction flows across multiple blockchain networks — both EVM and non-EVM.
  • Own end-to-end development of backend components and APIs — from architecture decisions to production deployment.
  • Lead integrations with DeFi protocols, on-chain data sources, and blockchain nodes across a wide range of chains and ecosystems.
  • Research and evaluate emerging blockchain technologies, protocols, and standards to keep Fireblocks at the cutting edge.
  • Optimize existing production systems for performance, reliability, and security — reducing latency and increasing throughput.
  • Collaborate closely with product, protocol research, and platform engineering teams to deliver high-quality solutions on time.
  • Drive features from inception through to delivery at scale, taking full ownership of the product lifecycle.

What You'll Bring

  • 7+ years of experience as a Backend or Full Stack Engineer.
  • Bachelor of Science (B.Sc.) or equivalent degree/experience.
  • Blockchain and Web3 experience are a must — including deep understanding of transaction lifecycles, consensus mechanisms, smart contract interactions, and on-chain data.
  • Proven experience working across multiple blockchain ecosystems — EVM-compatible chains (Ethereum, Polygon, Arbitrum, Base, etc.) as well as non-EVM chains such as Solana, TON, Tron, or similar.
  • Proficiency in Node.js and TypeScript.
  • Experience designing and operating microservices in production CI/CD environments.
  • Strong understanding of security principles, cryptography, and best practices in a blockchain context.
  • Familiarity with DeFi protocols — AMMs, lending markets, bridging infrastructure, or on-chain routing — is a strong advantage.
  • Experience with Web3 tooling and libraries (ethers.js, viem, web3.js, Solana web3.js, etc.).
  • Demonstrated experience taking products from inception to delivery at scale.
  • Full stack experience (React, frontend development) — a nice to have.

About You

  • You think in systems and care deeply about correctness, reliability, and scale.
  • You're comfortable navigating ambiguity and can drive technical decisions with limited oversight.
  • You have a natural curiosity for how blockchain protocols work under the hood — and you actually read the specs.
  • You thrive in fast-moving environments and can balance shipping velocity with long-term code quality.
  • You communicate clearly and collaborate effectively across engineering, product, and research.

Why Fireblocks

  • Work at the frontier of blockchain infrastructure, with real impact on how DeFi scales for institutional and retail users.
  • Tackle genuinely hard engineering problems — multi-chain routing, on-chain data indexing, protocol integrations, and more.
  • Collaborate with world-class engineers, protocol researchers, and product minds in a fast-growing global company.
  • Competitive compensation, meaningful equity, and a culture that rewards ownership and initiative.

Fireblocks' mission is to enable every business to easily and securely access digital assets and cryptocurrencies. In order to do that, we strongly believe our workforce should be as diverse as our clients, and this is why we embrace diversity and inclusion in all its forms. 

Please see our candidate privacy policy here.

How we rate this

Full Stack Engineer, Blockchain at Fireblocks rates 0 out of 100 for how much of the daily work is AI. That makes it Little AI (AI Level 1 of 4). The level is about AI in the job, not seniority.

Classification

Little AI. AI is not part of the work.

  1. ●●●● Builds AI80 to 100
  2. ●●●○ Works on AI60 to 79
  3. ●●○○ Uses AI40 to 59
  4. ●○○○ Little AI0 to 39

Levels come from how often the tools, models and workflows of the role are named in the posting itself. Read the description and count the AI tools, models and workflows it names.

Prepare for this job

Built from this posting and from similar jobs on Level.

Skills and AI tools this role asks for

BlockchainDefiBackendSmart ContractsAPI

Also common in software engineer jobs at this level

Pay

Typical software engineer job
$168k

This posting doesn't list pay. Use the typical software engineer figure when pay comes up. See software engineer jobs

Questions you could be asked

  1. Tell me about a project where blockchain was part of your work. What did you do?
  2. Tell me about a project where defi was part of your work. What did you do?
  3. Tell me about a project where backend was part of your work. What did you do?
  4. Tell me about a project where smart contracts was part of your work. What did you do?
  5. Tell me about a project where api was part of your work. What did you do?

Adapt your resume

  • List these exact terms on your resume: Blockchain, Defi, Backend, Smart Contracts, and API. An applicant tracking system matches the wording, not the idea.
  • Attach one line of real, concrete experience to at least one of them. A tool named with nothing behind it rarely survives a human read.

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