Senior Freelance Lead Software Engineer 2c Developer Api in Amsterdam

About BlockTech BlockTech is an algorithmic trading firm operating at the frontier of global crypto derivatives and spot markets. We trade 24/7 across some of the fastest-moving, most data-rich venues in finance. Crypto remains one of the few markets where a researcher can still meaningfully move the edge: abundant data, novel microstructure, and the shortest possible loop between a research idea and live PnL. We're looking for an experienced Quantitative Researcher to take ownership of that edge and push it further. The role This is a senior, hands-on research seat on our trading floor. You'll own a research agenda end-to-end from hypothesis, dataset construction, feature engineering, model training, backtesting, live deployment, monitoring, and iteration. You'll be trusted to set its direction. You'll work shoulder-to-shoulder with fellow researchers, traders and analysts, shape how we price and trade, and help raise the bar for research across the floor, including mentoring less experienced researchers and influencing the tools and standards the team relies on. You will: Own price-prediction, signal, execution, and anomaly-detection models across crypto derivatives and spot markets from idea to live PnL using state-of-the-art ML Shape our research, backtesting, and trading infrastructure together with engineers, so good ideas reach production quickly and safely Own models in production: monitor live performance, diagnose decay, and iterate on what you ship Set research direction alongside traders, deciding which trades are worth making and why Raise the research bar by mentoring colleagues, reviewing work, and setting standards for rigour What we're looking for 4+ years of hands-on quantitative research and/or applied ML experience, with a track record of models you've taken into production trading live A strong academic foundation in a quantitative discipline (mathematics, physics, statistics, computer science, ML/AI, or similar) Fluency in Python and the modern

About BlockTech BlockTech is a fast-paced algorithmic trading firm facilitating global cryptocurrency derivatives and spot trading while expanding into new markets. As we continue to grow rapidly, we are looking for a Senior Software Engineer to take technical ownership of our Core systems and help shape how they evolve through our scale-up phase. This is a role for an engineer who has already built and operated correctness-critical systems at scale and who wants their technical decisions to set direction, not just follow it. What will you do? You will own the systems that keep our trading operation accurate at every level — positions, PnL, instruments, hedging, and the data flowing between them. Across exchanges and asset classes, your work determines whether the numbers our traders and risk team rely on are correct. As a senior engineer, you will also set the technical standards the rest of the team builds against. You will: Own the books. Maintain and evolve our position, trade, and PnL systems so they remain accurate across every venue. Architect the platform that supports trading. Design services that handle real-time exchange flow with the throughput and reliability our quoting and hedging depend on, making the structural calls that keep them fast and correct under load. Own the data flows. Operate and harden the public and private pipelines bringing market prices, account state, and trade events into our systems in real time. Lead venue integrations end-to-end. Deliver exchange and prime-broker integrations across protocol, account model, settlement, reconciliation, and surveillance and define the patterns we reuse for the next one. Model the instrument universe. Own the systems describing every tradable instrument - lifecycle, expiry, margin, RFQs, fast-path quoting - where both correctness and latency matter. Build self-healing systems. Design the detection and repair flows that identify position discrepancies and correct them automatically. Own hedging inf

About BlockTech BlockTech is a fast-paced algorithmic trading firm facilitating global cryptocurrency derivatives and spot trading while expanding into new markets. As we continue to grow rapidly, we are looking for a Software Engineer to join our Foundation team amid our exciting scale-up phase! You will Build & optimize: Design, develop, and maintain high-reliability, low-latency, and high-throughput foundational systems that enable our trading and technology teams to scale efficiently. Ingest & aggregate: Collect trading business data with minimal latency impact and ingest both public and private exchange information into our trading system. Store & stream: Develop and maintain infrastructure for real-time data aggregation and long-term storage, as well as our Kafka-based messaging systems. Collaborate & support: Work closely with multiple teams, assisting them in integrating with and making the most of our foundational systems. Innovate: Drive projects from concept to deployment with full ownership, and explore new tools, frameworks, and approaches to keep our infrastructure best-in-class. The Foundation team develops core software infrastructure (libraries, frameworks, and systems) for BlockTech, solving common problems and lending its expertise to enable other teams to stay focused on their respective domains. They own, develop, and configure a wide variety of critical, high-reliability software, ranging from low-level ultra-low-latency shared memory IPC libraries to high-throughput data buses and data aggregation systems including Kafka, NATS, PostgreSQL, and Iceberg. They work primarily in Rust, but also use Python and SQL. If you thrive on low-level problem-solving, building robust frameworks from scratch, and enabling others to move faster, this role is for you. What We're Looking For Essential: 5+ years of experience as a Software Engineer, with a strong focus on systems-level optimisation and awareness of hardware constraints Proficiency

About Sentry Software runs the world and the pace is faster than ever. Sentry helps developers fix errors and performance issues before users notice, so teams can spend less time firefighting and more time building. Trusted by 200,000+ organizations, Sentry is today’s application monitoring standard and our team is building its AI-native future. About the role: Sentry is expanding our Technical Customer Success team to support our growing customer base and drive deeper adoption of the Sentry Platform worldwide. As a Technical Customer Success Manager (TCSM), you’ll be a Sentry product expert responsible for ensuring customers are successfully onboarded, achieve maximum value from our platform, and uncover new opportunities for growth through additional use cases and products. You’ll play a key role in helping customers realize measurable outcomes with Sentry. In this highly cross-functional role, you’ll collaborate closely with Account Executives (AEs), Sales Engineers (SEs), and Engineering teams to ensure customers’ technical and business goals are met. This role requires strong technical expertise and a deep understanding of the Software Development Life Cycle (SDLC) and related technologies. If you’re a technologist with experience supporting technical products in customer-facing roles—and you’re eager to join a fast-growing team delivering real value through an exceptional product—we’d love to meet you. This is a one year fixed contract with potential for conversion after the one year. In this role you will: Become a Sentry product expert and support customers by understanding their needs and helping them achieve their goals using the Sentry Platform. Drive customer success and health through effective onboarding, adoption, value realization, and retention. Collaborate with customer key stakeholders to define business and technical objectives, and work with the customer team to achieve them. Act as a trusted, strategic advisor to each assigned customer—driving