Web3 Security Jobs in London, United Kingdom

About the Job

zerohash's Applied AI team manages two fronts: an internal Intelligence Core (a system connectivity and control layer) and external agentic-commerce products. This role acts as the engineering backbone for both—building the access layer, audit logging, skills/agents, and system architecture. The Applied AI team builds the Intelligence Core itself. Engineering maintains platform accounts, event hooks, and retrieval layers; this role builds everything above them.

Core objective: Connect company systems securely, and produce records of agent action that a third party can verify.

Strategic importance: The internal build acts as a sandbox for agentic commerce products. Identity, authority, write permissions, and tamper-evident logging will be proven internally before powering multi-institutional agentic networks.

Responsibilities

• Own the access layer (native connectors, MCP servers, Databricks US/EU) using short-lived tokens, least-privilege read-only access, and zero raw PII while enforcing data residency.
• Define a versioned schema for two signed record types of credentials and action records, in one namespace so each can be checked against the other.
• Establish build discipline early: deployment pipelines, authority policy as code, skill merge gates, and signed builds with SBOMs.
• Build the authority lease service with integrated kill switches.
• Capture events into append-only, hash-chained logs for tamper-evident and independently verifiable auditing.
• Migrate the team’s existing agents onto the Core, launch new per-department agents and lead security reviews for continuous read access.
• Extend the Core from read to bounded write: logged actions, idempotency keys, compensating actions, and multi-approver time-locks for anything that moves money.
• Design core primitives for cross-institution interoperability, wrapping actions in signed mandates, scoped authority, and attestation receipts compatible with standards like x402, AP2, and MPP.
• Design self-hosted, zero-egress private stacks when required by classification evidence.
• Evaluate and integrate state-of-the-art developments in agent frameworks, confidential inference, and zero-knowledge attestations.
• Maintain a security-first posture by threat-modeling prompt injection, credential exfiltration, and confused-deputy risks upfront.

Requirements

• Senior, Python-first backend engineering with production experience in event-driven systems, API integration, and CI/CD.
• Agent-system experience — composing LLM agents (Claude, GPT, or comparable; Bedrock or comparable platforms) into standing systems — with the judgment to keep the models at the edges and the control plane deterministic.
• Demonstrate security-first habits in a regulated environment (MSB/VASP, bank, or comparable): least privilege and read-only as reflexes, not requirements to be reminded of.
• Working familiarity with capability-based authorization: attenuable tokens, workload identity, policy-as-code.

Preferred

• Verifiable credentials, HTTP message signatures, or any of the emerging agent-payment mandate schemes (x402, AP2, MPP, Visa TAP, Mastercard Agent Pay).
• Self-hosted LLM stacks; confidential computing / trusted execution environments.
• A research habit and autonomy: this is a foundational seat on a new team, with wide scope and few hand-holds.

Benefits

• Healthcare Insurance: zerohash covers roughly 100% of employee premiums as well as a portion of spouse/children (U.S. only)
• Vision & Dental Insurance (U.S. only)
• Chance to earn equity
• Maternity & Paternity leave (after 6 months)
• WeWork All Access Membership
• WFH Yearly Stipend
• L&D Yearly Stipend (after 6 months)

About zerohash

zerohash is the leading crypto and stablecoin infrastructure platform and the operating system for digital money, powering the next generation of financial services. Founded in 2017, zerohash enables banks, brokerages, fintechs, and payment companies to offer crypto trading, stablecoin payments, and tokenized assets without having to build or manage complex blockchain infrastructure on their own.The zerohash platform supports three core pillars: Trade, Transact, and Tokenize. Through a single integration, customers can launch regulated crypto buy, sell, and custody services; enable 24/7 stablecoin-based funding, payouts, and settlement; and issue and manage tokenized assets with built-in compliance, risk controls, and reporting. By abstracting away technical, regulatory, and operational complexity, zerohash allows partners to treat digital assets as just another financial primitive: fast, programmable, and global.zerohash is trusted by some of the world’s most recognized financial and consumer brands, including Interactive Brokers, Morgan Stanley, Stripe, Franklin Templeton, BlackRock, DraftKings, Gusto, Worldpay, Kalshi, One Pay, among others. Today, zerohash infrastructure supports millions of end users across brokerage, wealth, payments, and marketplace platforms globally.The company is deeply regulated and compliance-first, operating across the U.S. and internationally with licenses and approvals that allow partners to enter crypto and stablecoins with confidence. zerohash has become a trusted partner for enterprises seeking to modernize financial products while meeting the highest standards for security, risk management, and regulatory oversight.To date, zerohash has raised over $280 million in funding from a mix of leading venture firms and strategic investors, including Morgan Stanley, Interactive Brokers, SoFi, Point72 Ventures, Bain Capital Crypto, Lightspeed Venture Partners, and more.zerohash has been featured in top-tier media outlets such as Bloomberg, CNBC, The Wall Street Journal, Financial Times, Reuters, Forbes, and CoinDesk, and its leadership team regularly contributes to global conversations on the future of payments, investing, and financial infrastructure.At zerohash, we're building the infrastructure that makes digital money work securely, compliantly, and at global scale.

The zerohash Culture

All zerohash employees are guided by the following characteristics and core principles:

• Independence/Ownership - An ability to work autonomously. Join zerohash, pitch ideas, and shape the work you do.
• Passion - We are innovating quickly and challenging the status quo. We want you to think big, be creative and ​make a difference every day.
• Collaborative - A good attitude and respect for others. We’re teammates, not co-workers. Everything we do is a shared success and equally a shared failure - we talk in terms of “we” not “me”.
• Initiative - An ability and passion for learning and asking questions. We will champion you, challenge you and push you to achieve your best - and we expect you to do the same.
• Empathy - An ability to listen, respect, and understand your co-workers, customers, and everyone you interact with no matter how different they are to you.
• Adaptability - An ability to respond quickly. We are in a fast-paced industry and so we expect you to be creative when solving a new problem and comfortable under pressure.
• Transparency - We believe that transparency is critical to empowering everyone to make the best decisions, both the company to its people and vice versa.
• Integrity - Integrity creates trust. As both an organization collectively and as individuals, it is our most valuable asset.

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For candidates based in Colorado, please contact colorado-wages @zerohash.com to request compensation and benefits information regarding a particular role(s). Please include with your email the city you reside (or intend to reside in Colorado) and the title/link to the roles you're interested in.

**We’ve recently seen an increase in individuals impersonating zerohash recruiters to target job seekers. Please stay vigilant and keep the following in mind to ensure you are communicating with the real zerohash team:

• Verified Emails Only: Official outreach will only come from a @zerohash.com email address.
• No Messaging Apps: We will never contact you via unsolicited text messages, WhatsApp, or Telegram.
• Official Applications: Only apply directly through our careers webpage (zerohash.com/careers) or zero-hash.breezy.hr.

See something suspicious?If you want to verify an interview request or report a fake job posting or suspicious communication, please contact us immediately at talent @zerohash.com. This email is for fraud reports only. Candidate application inquiries will not be responded to.