Senior Machine Learning Engineer

Senior Machine Learning Engineer II, Search & Recommendations Ranking

Instacart

We're transforming the grocery industry At Instacart, we invite the world to share love through food because we believe everyone should have access to the food they love and more time to enjoy it together. Where others see a simple need for grocery delivery, we see exciting complexity and endless opportunity to serve the varied needs of our community. We work to deliver an essential service that customers rely on to get their groceries and household goods, while also offering safe and flexible earnings opportunities to Instacart Personal Shoppers. Instacart has become a lifeline for millions of people, and we’re building the team to help push our shopping cart forward. If you’re ready to do the best work of your life, come join our table. Instacart is a Flex First team There’s no one-size fits all approach to how we do our best work. Our employees have the flexibility to choose where they do their best work—whether it’s from home, an office, or your favorite coffee shop—while staying connected and building community through regular in-person events. Learn more about our flexible approach to where we work. Overview The Search & Personalization ML team is Instacart’s engine for state-of-the-art multi-task, multi-objective ranking—unifying search, discovery, recommendation, ads, and merchandising into a single value-aware platform. Partnering with world-class engineers, scientists, and PMs, we build the ranking backbone that powers every pixel of the shopping journey, optimizing not just for clicks, but for incremental GTV, basket lift, and retention over the long run. What We’re Building * Foundational Ranking Backbone Models: Multi-task/multi-objective models (shared encoders + task heads) that jointly learn relevance, conversion, margin contribution, churn risk, and ad quality, enabling consistent decisions across search and recommendations. * Value-Aware Optimization: Uplift and long-horizon value models that steer decisions toward incrementality and LTV, with calibrated constraints on quality, diversity, fairness, and spend pacing—plus guardrails for safe exploration. * LLM-Enhanced Retrieval & Features: Using LLMs to enrich query and item semantics for long-tail recall, generate features for cold-starts, and feed the ranker with reasoning-rich context, while remaining the source of truth for final ordering. Our commitment to AI innovation is reflected in our recent publications and research contributions to the field.   About the Job * Architect the ranking backbone that unifies query understanding, personalization, multi-objective ranking, ads, and merchandising into a single adaptive platform. * Design and build a search autosuggest system optimized for personalization and value-based relevance. * Design long-horizon objective functions (e.g., incrementality, LTV, habit formation) and build uplift/causal value models that move beyond short-term engagement. * Develop production-grade Multi-Task Learning (e.g., shared encoders, MMOE/PLE task heads) to jointly learn relevance, propensity, margin, and churn risk—ensuring calibration, constraints, and explainability. * Own the inference layer: goal-aware re-rankers, diversity and quality constraints, safe exploration, and millisecond-class latency optimization. * Advance evaluation practices: online experiments, long-horizon cohort metrics, counterfactual evaluations, and attribution pipelines for tracking incremental GTV and retention. * Partner across ads, infrastructure, product, and design teams to translate business goals into ranking policies and measurable ROI. * Mentor ML engineers to build expertise in ranking, causal inference, and scalable serving systems.   About You Minimum Qualifications * 5+ years applying ML at scale (3+ years in technical leadership), with a proven track record improving ranking or recommendation systems in production. * Demonstrated success in applying multi-objective or constrained optimization to balance relevance, revenue, margin, and user experience; experience with online testing and attribution beyond CTR. * Strong coding (Python) and data fluency (SQL/Pandas), with expertise in classic ML techniques (e.g., XGBoost) and deep learning frameworks (TensorFlow/PyTorch). * Excellent analytical skills and strong cross-functional communication abilities. Preferred Qualifications * Expertise in multi-task learning architectures (e.g., MMOE/PLE, shared encoders), calibration, counterfactual evaluation, uplift/causal modeling, and/or contextual bandits for exploration. * Experience building low-latency ranking services, including feature stores, caching, vector + lexical retrieval, re-ranking, and A/B testing infrastructure, with expertise in constraint-aware inference. * Hands-on experience with LLMs as feature/recall enhancers (e.g., embeddings, adapter tuning) while maintaining clarity on when the ranker should arbitrate. Instacart provides highly market-competitive compensation and benefits in each location where our employees work. This role is remote and the base pay range for a successful candidate is dependent on their permanent work location. Please review our Flex First remote work policy here. Offers may vary based on many factors, such as candidate experience and skills required for the role. Additionally, this role is eligible for a new hire equity grant as well as annual refresh grants. Please read more about our benefits offerings here. For US based candidates, the base pay ranges for a successful candidate are listed below. CA, NY, CT, NJ $207,000—$253,500 USD WA $198,000—$243,000 USD OR, DE, ME, MA, MD, NH, RI, VT, DC, PA, VA, CO, TX, IL, HI $190,000—$233,000 USD All other states $173,000—$212,000 USD

Principal Machine Learning Engineer

Toast

Toast creates technology to help restaurants and local businesses succeed in a digital world, helping business owners operate, increase sales, engage customers, and keep employees happy. Toast is looking for a hands-on Principal Software Engineer to join the AI & Strategy Engineering team. In this role, you will be a primary builder of 0-to-1 tools designed to revolutionize how our sales teams operate. This isn't about maintaining legacy systems; it’s about writing the code and building the intelligence models that eliminate friction across the Go-To-Market stack. Working under a Senior technical leader, you will be responsible for the "heavy lifting" of backend engineering and Machine Learning implementation. You will bridge our custom quoting software and Salesforce with intelligent, agentic workflows that allow sales users to make faster, data-backed decisions.   A day in the life (Responsibilities)  * Hands-on Execution: Spend the majority of your time "hands-on-keyboard," architecting and coding high-performance backend services and ML pipelines. * 0-to-1 Development: Build and prototype new internal products from scratch that leverage LLMs and Agentic AI to automate account research, lead prioritization, and complex quoting logic. * Core Intelligence Models: Design and implement ML models that provide real-time recommendations to sales users, reducing manual entry and increasing deal velocity. * Infrastructure Integration: Develop the backend connective tissue between our custom quoting engine, Salesforce, and internal data lakes to ensure a seamless, low-latency end-to-end experience. * Technical Problem Solving: Act as a domain expert to solve complex synchronization and architectural challenges across the GTM stack, ensuring systems are scalable and resilient. * Quality & Mentorship: Drive engineering excellence through rigorous code reviews, automated testing, and by modeling best practices for SE1-SE3 engineers on the team. * Build Great Products: Deliver significant core capabilities that have broad impact; take high-level goals and turn them into sequenced, production-ready code. * Problem Solve: Anticipate shifts in product needs and build flexible, decoupled backend systems that can evolve with our AI strategy. * Deliver Quality: Ensure the reliability of GTM tools by building deep observability into every service you ship.   What you'll need to thrive (Requirements) * Deep Backend Expertise: Extensive experience in backend languages (Java, Go, Python) with a track record of building complex, distributed systems. * Applied AI/ML Skills: Practical, hands-on experience deploying Machine Learning models and building with LLMs (e.g., LangChain, RAG architectures, or Model Fine-tuning) in a production environment. * Technical Complexity: Experience building or deeply integrating with complex enterprise software, specifically custom quoting engines or CRM internals (Salesforce Apex/LWC). * Systems Architecture: Ability to design event-driven architectures and manage data flow across disparate systems with high integrity. * Education: Bachelor’s or Master’s degree in Computer Science, or a related technical field.   What will help you stand out (Nonessential Skills/Nice to Haves) * Experience building internal "Sales Tech" or "Fintech" tools that directly impact revenue. * Familiarity with AWS data services (SageMaker, Lambda, SQS). * A passion for removing "human-in-the-loop" friction through intelligent automation.   AI at Toast At Toast, one of our company values is that we're hungry to build and learn. We believe learning new AI tools empowers us to build for our customers faster, more independently, and with higher quality. We provide these tools across all disciplines, from Engineering and Product to Sales and Support, and are inspired by how our Toasters are already driving real value with them. The people who thrive here are those who embrace changes that let us build more for our customers; it’s a core part of our culture.   Our Total Rewards Philosophy  We strive to provide competitive compensation and benefits programs that help to attract, retain, and motivate the best and brightest people in our industry. Our total rewards package goes beyond great earnings potential and provides the means to a healthy lifestyle with the flexibility to meet Toasters’ changing needs. Learn more about our benefits at https://careers.toasttab.com/toast-benefits. #LI-Remote The base salary range for this role is listed below. The starting salary will be determined based on skills, experience, and geographic location. In addition to base salary, our total rewards components include cash compensation (overtime, bonus/commissions if eligible), equity, and benefits. You can learn more about how we align pay with local labor markets in our Geographic Pay Zone Philosophy. Zone A $230,000—$368,000 USD Zone B $200,000—$320,000 USD Zone C $180,000—$288,000 USD How Toast Uses AI in its Hiring Process Throughout the hiring process, our goal is to get to know you. We use AI tools to support our recruiters and interviewers with tasks like note-taking, summarization, and documentation of interviews to ensure they can be fully focused on your conversation. All hiring decisions are made by people. To learn more: https://careers.toasttab.com/ai-in-hiring Our Approach to Hybrid Working We embrace a hybrid work model that fosters in-person collaboration while valuing individual needs. Our goal is to build a strong culture of connection as we work together to empower the hospitality community, regardless of location. Please visit the Locations page on our career site to learn more about our in-office expectations by region: https://careers.toasttab.com/locations-toast Diversity, Equity, and Inclusion is Baked into our Recipe for Success At Toast, our employees are our secret ingredient—when they thrive, we thrive. The restaurant industry is one of the most diverse, and we embrace that diversity with authenticity, inclusivity, respect, and humility. By embedding these principles into our culture and design, we create equitable opportunities for all and raise the bar in delivering exceptional experiences. We Thrive Together We embrace a hybrid work model that fosters in-person collaboration while valuing individual needs. Our goal is to build a strong culture of connection as we work together to empower the restaurant community. To learn more about how we work globally and regionally, check out: https://careers.toasttab.com/locations-toast. Apply today! Toast is committed to creating an accessible and inclusive hiring process. As part of this commitment, we strive to provide reasonable accommodations for persons with disabilities to enable them to access the hiring process. If you need an accommodation to access the job application or interview process, please contact candidateaccommodations@toasttab.com. ------ For roles in the United States, it is unlawful in Massachusetts to require or administer a lie detector test as a condition of employment or continued employment. An employer who violates this law shall be subject to criminal penalties and civil liability.

Senior Security Engineer - Remote

Parity

ABOUT US Parity is one of the world’s most experienced companies building the core infrastructure behind blockchain — the system that allows information and value to be shared securely without needing an intermediary. We’re laying the foundation for a better web which respects the freedom and data of individuals, and empowers developers to build better, more trustworthy online services. Our remote-first, global team develop open-source software that anyone can use or improve. This includes Polkadot, Polkadot SDK, and Kusama — key parts of the Web3 tech stack, the next generation of the internet. Our mission is to make Polkadot the most active and innovative community in blockchain, powering a new era of connected and decentralised applications. ABOUT THE TEAM Parity’s Security Engineering team is at the forefront of protecting the Polkadot ecosystem by designing and implementing secure software, auditing code for vulnerabilities, and building cutting-edge ML tools to automate security analysis. We work closely with development teams to embed security best practices across our open-source stack, ensuring that our blockchain infrastructure is robust, resilient, and secure by design. ABOUT THE ROLE As a security-focused software engineer, you will go beyond traditional application security - you’ll audit and ideally write secure Rust code where needed, conduct deep manual and automated code audits, and leverage machine learning to enhance security across our ecosystem. This is an opportunity to shape the security landscape of the next generation of decentralized applications and protocols. * Assist in developing Secure Software – Write and optimise Rust code to build security-critical components and tools. * Code Auditing & Vulnerability Analysis – Perform deep manual and automated code reviews to identify and mitigate security vulnerabilities. * ML-Powered Security – Design and implement machine learning models for automated security analysis, anomaly detection, and threat mitigation. * Bug Bounty & Vulnerability Management – Manage bug bounty submissions, triage security reports, and collaborate with ethical hackers to resolve issues. * Secure Development Best Practices – Work with engineering teams to integrate security best practices into the software development lifecycle. * Threat Modeling & Risk Assessment – Identify and assess security risks in our blockchain infrastructure, smart contracts, and core software. * Stay Cutting-Edge – Research and implement the latest advancements in secure coding, ML-driven security, and blockchain security. WHAT WE'RE LOOKING FOR * Experience with secure coding practices and memory safety concepts. * Background in code auditing, vulnerability analysis, or exploit development. * Experience triaging and resolving bug bounty reports. * Knowledge of machine learning techniques applied to security (e.g., anomaly detection, fuzzing, automated threat detection). * Familiarity with cryptographic principles, blockchain security, or decentralized systems. * Strong problem-solving skills and an offensive security mindset. If you're excited about writing secure software, auditing code, and pioneering ML-driven security solutions for Web3, we’d love to hear from you! ABOUT WORKING WITH US Joining Parity means joining team mates who are genuinely excited about the impact their projects are having, and the opportunity to grow alongside some of the brightest minds in the Web3 space! You’ll work remotely and flexibly, while still getting to meet your team mates throughout the year at team and company-wide retreats. Upon receiving an offer, all candidates undergo a background check through Zinc, our trusted third-party provider. Team members will be taken on as a contractor via our UK entity. View our Applicant Notice to see how we use your data. Parity is an Equal Opportunity Employer. We welcome diversity in our global team and care about everyone in our collective feeling included and welcome. Is this position not quite your match? Browse our other open roles.