Backend Software Engineer - Payments & Digital Money

Location: New York (Hybrid)

Compensation: $150K - $180K

We are a lean and mighty team of passionate builders, funded by top investors in fintech and crypto, focused on empowering the next generation of money and financial products globally. We are seeking a Backend Software Engineer to join us at the cutting edge intersection of real-world payments and digital money, where you will deliver massive impact within a small, quickly growing company.

You will be a critical part of defining our technical and product roadmap, contributing directly to our core backend infrastructure. This role involves rapid feature shipping, large-scale system scaling, and integrating with diverse third-party services and smart contracts across multiple chains. You will have the freedom to explore ideas, impact the company's vision, and grow into the role that best aligns with your personal goals.

What You'll Do:

Commercial Counsel - Blockchain Infrastructure

Location: Remote - Must be in the European Union (remote-first, office optional). France/ Paris or as close as possible, is always preferred.

Compensation: $95K - $140K

Join a stellar team of leaders and experts building the backbone of blockchain wallet infrastructure for the next financial era. We are hiring a Commercial Counsel to own and drive all contract-related legal matters for our platform. Reporting directly to the CEO, you will play a hands-on, critical role in supporting our international growth while ensuring compliance within the fintech and crypto regulatory landscape.

This is a high-autonomy role where you will be directly responsible for accelerating deal flow while protecting the company's interests. You will act as a key partner to our Sales, Product, and Operations teams, responsible for building the scalable legal foundation that supports our expansion across the globe.

Responsibilities:

Backend Data Engineer - Real-Time Crypto Analytics Infrastructure

Location: London, New York City (Office)

Compensation: $250K - $300K

We are a high-growth software development company of elite builders, redefining what's possible and proud contributors to the largest crypto social network globally. We are seeking a Backend Engineer focused on data to design and scale our real-time data infrastructure at the forefront of crypto and social finance. This role is for a self-starter who thrives on solving complex, high-throughput data challenges in a fast-paced environment.

You will own the end-to-end architecture and operation of our real-time analytics pipeline, ensuring low-latency insights are always available to internal and external stakeholders. This role requires interacting directly with high-throughput blockchain infrastructure and solving significant challenges related to data consistency, scale, and performance.

What You'll Do:

Are you passionate about building secure, reliable, and cost-efficient cloud environments?

At Keycafe, we’re looking for a Security & DevOps Engineer to strengthen our production systems, automate infrastructure processes, and enhance our overall security posture. You’ll work across software, infrastructure, and compliance — ensuring our global IoT platform remains fast, reliable, and trusted by customers worldwide.

This is a high-impact role where you’ll streamline deployments, optimize resources, and guide the team in DevOps best practices — helping Keycafe scale efficiently while maintaining world-class security.

What You’ll Do

• Deploy and manage production application updates across environments.
• Monitor production performance metrics (query times, response times, system reliability).
• Track and investigate production errors through logging and telemetry systems.
• Manage and optimize IaaS accounts (Heroku, Cloudflare, and related cloud services).
• Continuously evaluate and reduce cloud resource costs.
• Support and maintain InfoSec compliance (SOC 2 and other relevant accreditations).
• Maintain clear, up-to-date documentation of infrastructure and security processes.
• Collaborate with developers to automate manual tasks and improve deployment pipelines.

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:

Smart Contract Developer - Institutional DeFi Protocol

Location: Remote - US only (preference for onsite/hybrid in LA)

Compensation: $160K - $180K

We are an on-chain financial infrastructure company backed by leading VCs, committed to upgrading financial markets through 24/7 instant settlement. Our first product is an institutional-grade smart contract protocol that facilitates interoperability and liquidity across tokenized financial assets and stablecoins. We are seeking a Smart Contract Developer to join our core engineering team and build the foundational infrastructure that bridges traditional finance (TradFi) and decentralized finance (DeFi).

This is a high-impact, hands-on role where you will design, develop, and deploy highly secure, robust smart contracts for our core protocol. You will architect on-chain logic, optimize gas efficiency, and ensure best-in-class security practices to enable institutional-grade DeFi operations. You will work within a small, senior team, collaborating closely with security auditors, product, and business stakeholders.

Key Responsibilities:

Solana-Focused Frontend Engineer - Crypto Social Finance

Location: Remote - preference is NYC/LDN but open to remote candidates if they're an exceptional fit.

Compensation: $250K - $300K

We are a high-growth software development company of elite builders, redefining what's possible and proud contributors to the largest crypto social network globally. We are seeking a Solana-Focused Frontend Engineer to play a critical role in building and scaling cutting-edge platforms at the forefront of crypto and social finance, delivering high-performance, user-centric applications across web and mobile.

You will be instrumental in bridging the gap between our smart contract infrastructure and the user interface, working in an environment where speed, ownership, and innovation are paramount. You will own the front-end implementation of new on-chain features, optimize performance, and ensure a seamless user experience for real-time interactions.

Key Responsibilities:

Senior Rust Engineer - On-Chain Security Infrastructure

Location: Remote - Europe

Compensation: $165K - $200K

We are building a Credible Layer—a step-level improvement for on-chain security designed to safeguard the crypto industry and restore credibility after billions were lost to hacks. We are creating an on-chain protocol and off-chain infrastructure that enables protocols to enforce security rules for every transaction. Backed by world-class investors, we are seeking a Senior Rust Engineer to work on bleeding-edge infrastructure at the heart of our mission.

You will play a crucial role in shipping cutting-edge features that extend the EVM (Ethereum Virtual Machine) to enable security rules to be checked after every state transition. This is a high-impact, deeply technical role requiring expertise in performance optimization and low-level systems programming within a collaborative, fast-iteration environment.

Key Responsibilities:

Senior Infrastructure Engineer - Blockchain Wallet Backbone

Location: Remote - Location: United States (remote-first, office optional). EST time is preferred

Compensation: $180K - $300K

Join a stellar team of leaders and experts in blockchain technology, cryptography, and security. We are building the backbone of blockchain wallet infrastructure for the next financial era. We are seeking a Senior Infrastructure Engineer to design, operate, and scale systems at the intersection of blockchain, cybersecurity, and distributed infrastructure, preparing us 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 our workflows, ensuring our 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:

Full Stack Engineer - Payments & FinTech Web Applications

Location: Remote - Based in EST or GMT+1

Compensation: $120K - $150K

We are a high-growth technology company building a robust FinTech and payments platform. We are seeking an experienced Full Stack Engineer with strong product sense and deep technical expertise to design and build the secure, scalable, and high-performing web applications that power our platform. This role requires translating complex backend financial systems into intuitive, reliable user experiences.

You will own the development lifecycle of web applications from design through release, working across the full stack with an emphasis on the frontend user experience. You will collaborate closely with backend teams, ensuring that all features prioritize performance, security, and scalability. You will be expected to treat UI components and APIs as products, maintaining high standards for code quality and architectural clarity.

What You'll Do: