Staff Backend Engineer

Location: London or New York City

Onsite | Full-time

Compensation: competitive

Our client is a high-performance technology development firm responsible for building and operating the infrastructure behind the world’s largest and most active digital asset launchpads. Processing approximately $1B in daily volume, the platform operates at the bleeding edge of crypto scale, requiring systems designed for ultra-low latency, high throughput, and constant high-concurrency load.

The organization is seeking a Lead Backend Engineer to own the most complex technical challenges across the system. This is a high-stakes, high-impact role within an intense, in-person environment. The team is composed of high-agency builders who value speed, immediate impact, and rigorous engineering judgment. This position is ideal for an engineer who thrives under pressure and is motivated by the opportunity to solve ambiguous, cross-cutting problems that others cannot.

Key Responsibilities

Overview 

We’re looking for a Mobile Engineer passionate about creating high-quality, user-focused applications that connect people through performance, movement, and data especially within sports and wearable technology ecosystems. 

Job Overview 

You will design, build, and maintain React Native applications for both Android and iOS. You’ll develop tools and experiences that connect users through sports and activity platforms, integrating with wearables and real-time data systems to deliver seamless tracking, analytics, and engagement. 

You’ll collaborate closely with backend developers, product managers, and designers to turn complex data and operational flows into intuitive, reliable mobile experiences. 

Key Responsibilities 

Senior Software Engineer - Developer Tools & SDKs

Location: Remote - US & Americas

Compensation: $ Competitive

We are a fast-growing software company dedicated to supporting and developing an EVM-compatible, open-source, proof-of-stake platform. This public network is engineered for enterprise and Web3 applications, prioritizing speed, security, stability, and sustainability, and is governed by industry-leading organizations. We are seeking an experienced Software Engineer to lead the development of world-class developer tools and SDKs.

You will take the lead on crafting seamless developer experiences, owning the design, build, and maintenance of our open-source SDKs and related tooling. This role requires technical leadership, hands-on coding across multiple languages, and a strong focus on developer empathy. You will work cross-functionally to ensure our tools are intuitive, robust, and aligned with real-world developer needs.

What You'll Be Doing:

Senior Infrastructure Engineer - Blockchain Wallet Backbone

Location: Remote - United States

Compensation: $180K - $300K

Join a stellar team of leaders and experts in blockchain technology, cryptography, and security. Our client is seeking a Senior Infrastructure Engineer to design, operate, and scale systems at the intersection of blockchain, cybersecurity, and distributed infrastructure, preparing them to meet the demands of a trillion-dollar industry.

This role goes beyond maintenance—you will be an architect, automator, and security expert. You will embed best-in-class DevOps and SRE practices into their workflows, ensuring their services are highly reliable, secure, and cost-efficient. You will collaborate across engineering, product, and security to translate complex requirements into scalable infrastructure.

Key Responsibilities:

Senior Blockchain Engineer - Encrypted Infrastructure

Location: New York (Office)

Compensation: $150K - $200K

We are a small, fast-moving software company building an encrypted blockchain that combines deep expertise in cryptography, compilers, and distributed systems. Backed by top-tier investors including a16z and Polychain, we are financially secure with several years of runway. We are seeking a Senior Engineer to join our elite team in New York City and work on cutting-edge, challenging engineering problems.

You will join a focused team of industry veterans and standout talent, taking on significant decision-making responsibilities as you design and implement core components of our encrypted platform. This role requires the commitment to bring hard, complex tasks to completion independently, contributing to infrastructure that is fundamentally redefining secure data handling on-chain.

Key Responsibilities:

Founding Engineer - High-Growth DeFi Mobile Trading App

Location: Remote - US Remote (Must be able to travel to NYC 2 weeks at a time, every 1-2 months for in person collaboration)

Remote | Full-time

Compensation: $200K - $300K

Our client is the creator of a leading decentralized finance (DeFi) application—often described as the “Robinhood for DeFi”—which allows users to trade cryptocurrencies on-chain through a seamless, user-friendly mobile interface. Since its launch in July 2024, the platform has successfully onboarded over 1.5 million users.

The organization’s mission is to onboard the world to decentralized finance, driven by the conviction that blockchain technology can build an open and accessible financial future. This is a lean team of passionate self-starters where every member acts as both a decision-maker and an implementer. As a Founding Engineer, the successful candidate will run toward the hardest problems alongside high-caliber teammates to shape the future of global finance.

Key Responsibilities

At Quento, the ICT arm of the Qualco Group, we deliver comprehensive and innovative solutions across AI, Digital Engineering, Cloud, and Cybersecurity, helping businesses accelerate digital transformation. With a presence in Greece, Luxembourg, and Belgium, and backed by the expertise of the Qualco Group, we combine deep technical knowledge with strategic partnerships to support business growth.

At Quento, we empower our people to innovate and lead in delivering transformative ICT solutions to our clients worldwide. Quento Technologies seeks a highly motivated and experienced IT Murex Consultant. The role will be part of the IT & FM FinApps team, under the Murex support function and will be responsible for the design, build and maintain MX Test, Back Office, Interfaces, and Reporting Murex modules.

Responsibilities:

Senior Core Systems Engineer - Secure Wallet Infrastructure

Location: Remote - Location: US or EU (remote-first, office optional). Must be in the US, not Canada or in the European Union. France or Paris or as close as possible, always preferred.

Compensation: $180K - $260K

Join a stellar team of leaders and experts in blockchain technology, cryptography, infrastructure, and security to build the backbone of blockchain wallet infrastructure for the next financial era. We are hiring a Senior Core Systems Engineer to design, build, and scale the low-level systems at the heart of our platform, where performance, security, and correctness are non-negotiable. This is a high-impact role focused on turning advanced cryptography into fast, resilient, and trusted production infrastructure.

As a Core Systems Engineer, you will work deep in the stack, designing and scaling reliable distributed services and integrating them with cloud, hardware, and blockchain environments. You will collaborate across product, research, and security to implement advanced cryptographic and security protocols using low-level systems languages.

Responsibilities:

Senior Backend Engineer - Stablecoin Infrastructure

Location: Remote - Based in EST timezone

Compensation: $175K - $225K

We are a technology company building a full-service platform that transforms how money moves. Our mission is to make digital dollars the core of a new, global financial fabric—faster, more efficient, and universally accessible. We are creating foundational infrastructure that makes issuing, managing, and integrating stable, dollar-based value on-chain seamless for developers, fintechs, and institutions. We are backed by world-class investors and are growing a team to reimagine how value moves online.

We are seeking a Senior Backend Engineer to accelerate the delivery of both critical internal tooling and high-impact customer-facing products. You will join a small, high-performance team that applies the discipline of high-performance finance to a fast-moving, crypto-native startup environment.

In this role, you will:

Lead Mobile Engineer - Fintech/Blockchain

Location: Remote - Location: US or EU (remote-first, office optional). Based in EST time zone preferably and as close to France, Paris is always the major preference.

Compensation: $140K - $220K

Our client is hiring a Lead Mobile Engineer to drive the user-facing side of our secure, next-generation financial platform. This remote-first role is focused entirely on mobile, requiring you to design, build, and refine iOS and Android applications, craft intuitive cross-platform interfaces, and shape the mobile SDKs that developers rely on. This is a critical opportunity to turn complex financial requirements into simple, trustworthy workflows while owning projects end-to-end.

As the Lead Mobile Engineer, you will set the technical direction for the user-facing mobile experience, balancing fintech-grade UX with bank-grade security and reliability. You will be responsible for bringing complex requirements into production quickly and rigorously.

Responsibilities: