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Research Engineer, Data Infrastructure (Language Modeling)

cartesia

OnSite *HQ - San Francisco, CA
Data Uncategorized

Job Score

80 pts
On-site model (+70) Data (+10)

About Cartesia

Our mission is to architect AI that learns from and interacts with the world like humans do.

We're pioneering the model architectures that will make this possible. Our founding team met as PhDs at the Stanford AI Lab, where we invented State Space Models or SSMs, a new primitive for training efficient, large-scale foundation models. Our team combines deep expertise in model innovation and systems engineering paired with a design-minded product engineering team to build and ship cutting edge models and experiences.

We're funded by leading investors at Index Ventures and Lightspeed Venture Partners, along with Factory, Conviction, A Star, General Catalyst, SV Angel, Databricks and others. We're fortunate to have the support of many amazing advisors, and 90+ angels across many industries, including the world's foremost experts in AI.

About the Role

Data is the lifeblood of our models, and we are looking for a Research Engineer, Data Infrastructure to build the datasets and systems that power pretraining at Cartesia. In this role, you will write performant, scalable infrastructure to acquire, process, and curate massive datasets, and partner closely with research to optimize the characteristics and composition of data mixtures. Your work will directly shape the capabilities and quality of our foundational models.

Your Impact

  • Build and operate performant, scalable data processing infrastructure for acquiring, ingesting, and combining massive text datasets.

  • Design and operate scalable, high-throughput, and reproducible data pipelines — covering ingestion, preprocessing, filtering, deduplication, and augmentation.

  • Design and run ablation experiments to understand how data sources, processing choices, and mixture weights affect model quality.

  • Partner closely with research and infrastructure teams to co-design data loading, versioning, and experimentation pipelines.

  • Establish and enforce rigorous standards for data quality, with a tight feedback loop between dataset characteristics and model behavior.

  • Identify and source novel datasets; manage relationships and budgets with external data vendors and partners.

What You Bring

  • Hands-on experience with ML data infrastructure: training data pipelines, dataset versioning, large-scale data loading, and the interplay between data systems and model training and inference.

  • Strong modern engineering execution: clean, well-tested code, fluency with current tools, and a willingness to pick the right tool for the problem rather than defaulting to familiar patterns.

  • Familiarity with building and evaluating datasets for generative models and reasonable working knowledge of how they're trained and inference.

Nice-To-Haves

  • Experience with large-scale data processing using parallel infrastructure such as Ray, Spark, or Kubernetes.

  • Experience with pretraining language models.

Note: Cartesia participates in E-Verify and will provide the federal government with Form I-9 information to confirm employment eligibility after hire.

More Details

🏢 In-office policy: We’re an in-person team based out of offices in 🇺🇸 San Francisco, 🇬🇧 London and 🇮🇳 Bangalore. We love being in the office, hanging out together, and learning from each other every day.

🌎 Visa sponsorship: We provide visa sponsorship support and assess each circumstance on a case-by-case basis. However, visa sponsorship is dependent on many factors, including the role you are applying for, and the location you are going to be based, and so we can't always guarantee success. Your Recruiter will work with you to understand your visa sponsorship needs from the first call.

🚢 We ship fast. All of our work is novel and cutting edge, and execution speed is paramount. We have a high bar, and we don’t sacrifice quality or design along the way.

🤝 We support each other. We have an open & inclusive culture that’s focused on giving everyone the resources they need to succeed.

Our Benefits (US Employees Only)

💰 Compensation Competitive base salary alongside attractive equity package.

🩺 Health Insurance Fully covered medical insurance along with dental and vision for you and your family.

🧑‍🧑‍🧒‍🧒 Parental Leave 9 weeks paternity & 12 weeks maternity leave

🏦 401(k)

🚆 Commuter Allowance A monthly stipend to help you get to and from the office.

🏖️ Flexible PTO Take as much time as you need to recharge your batteries.

🍲 Meals & Snacks Lunch, dinner and plenty of snacks, provided daily.

🦖 Your own personal Yoshi

Our Commitment to Equal Opportunity

Cartesia is an equal opportunity employer. We consider qualified applicants without regard to race, color, religion, sex, national origin, age, disability, veteran status, genetic information, or any other legally protected status.

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About Data

The Data field has undergone a radical transformation with the rise of Generative AI. Data professionals are fundamental for evidence-based decision-making across all industries.

Key specializations include Data Engineering, Data Science, Business Intelligence, Machine Learning Engineering, and Analytics. Tools like SQL, Python, Spark, dbt, and cloud platforms (AWS, GCP, Azure) are essential.

The data market continues with high demand and salaries among the most competitive in the technology sector, with many remote work opportunities.

Discover Other Areas

Understand the scope of work, key skills, and tools used in different career areas.

About Project Manager

The Project Manager is the professional responsible for planning, executing, and controlling projects end-to-end, ensuring they are delivered on time, within budget, and with the expected quality. With the growing complexity of businesses, project management professionals are fundamental to organizational success.

Key skills include planning and scheduling, scope, cost, risk, quality, and resource management, stakeholder communication, cross-functional team leadership, and use of agile and traditional methodologies. Certifications like PMP, PRINCE2, and Six Sigma are important differentiators.

Project Managers in technology companies are highly valued, especially those who master agile methodologies (Scrum, Kanban), tools like Jira and MS Project, and can deliver complex projects efficiently. The field offers opportunities from project analyst to head of PMO, with a focus on execution, governance, and business value.

About Talent Acquisition

Talent Acquisition is the strategic area responsible for attracting, selecting, and hiring the best professionals for the organization. Unlike traditional recruitment, TA acts as a strategic business partner, aligning talent acquisition with the company's long-term objectives.

Key skills include advanced sourcing, employer branding, labor market analysis, talent pipeline management, and candidate experience. Tools like LinkedIn Recruiter, ATS (Greenhouse, Lever, Ashby), and assessment platforms are essential.

TA professionals in technology companies are highly valued, especially those who master tech sourcing, workforce planning, and recruitment metrics like time-to-hire and cost-per-hire.

About SEO Analyst

The SEO Analyst is the professional responsible for optimizing websites for search engines, increasing organic visibility and qualified traffic. With the growing importance of digital marketing, SEO professionals are fundamental to any online presence strategy.

Key skills include on-page and off-page SEO, technical SEO, keyword research, SEO audits, link building, optimized content creation, and metrics analysis. Tools like Google Search Console, Google Analytics, Ahrefs, Semrush, Moz, and Screaming Frog are essential for daily work.

SEO analysts in technology companies are highly valued, especially those who master technical SEO, Core Web Vitals, and data-driven content strategies. The field offers opportunities from junior analyst to head of SEO, with a focus on organic growth, domain authority, and return on investment.

About Software Development

Software Development is one of the most dynamic and constantly evolving fields in the job market. Professionals in this area are responsible for creating, maintaining, and optimizing web, mobile, and desktop applications that impact millions of users daily.

Key languages and frameworks include JavaScript (React, Node.js, Vue.js), Python (Django, Flask), Java (Spring), PHP (Laravel), and TypeScript. Demand for full-stack developers continues to grow, especially in tech companies and startups.

Salaries range from entry-level to senior positions, with growing opportunities for remote work and international freelancing.

About Engineering

Software Engineering goes beyond traditional development, focusing on scalability, performance, and system architecture. Software engineers are responsible for designing infrastructures that support millions of simultaneous users.

Skills include microservices architecture, DevOps, cloud computing, application security, and performance optimization. Knowledge of containerization (Docker, Kubernetes) and CI/CD is increasingly required.

Senior software engineers are rare and highly compensated professionals, with opportunities at major global tech companies.

Career Guides

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Design Career Guide

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Marketing Career Guide

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Finance Career Guide

Financial market, investments, corporate finance, certifications, and strategies to grow in the financial field.

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Communication Career Guide

Journalism, PR, Corporate Communication, Content Marketing, and Multimedia Production.

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Administration Career Guide

Business Management, HR, Logistics, Consulting, Project Management, and Entrepreneurship.

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Data Career Guide

Data Science, Data Engineering, BI, Machine Learning, and AI. From training to the job market.

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Product Career Guide

Product Management, Product Ownership, Agile, Scrum, and OKRs. From strategy to execution.

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Tech & Remote Glossary

Stop getting lost in interviews and job descriptions

The job market, especially within tech and global companies, has developed its own dialect. Not understanding these acronyms can make you lose valuable opportunities or poorly negotiate your contract. To end this problem, we created the Definitive Glossary for the Remote Professional.

🏢 Work Models & Routine

Async (Asynchronous Work)
A communication model where responses don't need to be immediate. Instead of back-to-back meetings, the team relies on well-structured documents, threads, and messages. It's the gold standard for global companies spanning multiple time zones.
Sync (Synchronous Work)
The opposite of Async. It requires the team to be online and available at the same time for meetings, live chats, and real-time collaboration.
Daily / Stand-up
A quick daily meeting (usually 15 minutes) common in Agile (Scrum) methodologies. The team answers three questions: What did I do yesterday? What will I do today? Are there any blockers?
All-Hands / Town Hall
A company-wide meeting involving all employees. Usually led by the founders (C-Levels) to present results, new goals, and answer team questions.
1:1 (One-on-One)
A recurring individual meeting between a professional and their direct manager. It is used for career alignment, feedback, and problem-solving, not just for project status updates.

💰 Contracts, Benefits & Compensation

PTO (Paid Time Off)
Instead of strict, categorized leave policies, modern US companies usually offer a flexible pool of days (e.g., 20 days of PTO, or even "Unlimited PTO") that you can use for vacations, sick days, or personal matters, while receiving your regular compensation.
Equity / Stock Options
Company ownership. The startup offers you the right to buy shares at a heavily discounted strike price in the future. If the company grows, goes public, or is acquired, these shares can be highly lucrative.
Vesting (Vesting Schedule)
The rule that controls your Equity. It usually lasts 4 years. You don't get all the shares on day one; you "earn" them gradually as you stay with the company. A "1-year Cliff" means you must stay for at least one year to receive your first batch of shares.
RSUs (Restricted Stock Units)
Unlike Stock Options (where you have the right to buy the stock), RSUs are actual shares the company grants you as a bonus or part of your compensation package, following a strict Vesting schedule.
Independent Contractor (1099 / B2B)
The most common international hiring model for global talent working for US companies. You act as a service provider (business-to-business), receiving the gross salary (often six-figure compensation) without standard local payroll tax deductions at the source.

🤖 Recruitment & Hiring Process

ATS (Applicant Tracking System)
The "robot" that reads your resume. Software like Greenhouse, Ashby, and Workday are used to filter candidates by keywords before a human even looks at the document. (Pro tip: this is why your resume must be clean, semantic, and have the right keywords).
JD (Job Description)
The document that lists the responsibilities, technical requirements, and benefits of the open position.
Cultural Fit
The interview stage that evaluates if your core values, communication style, and worldview align with the company's culture. This is the ultimate test of your Soft Skills.
Onboarding
The integration process. It's the period of your first few weeks at the company, where you get your access credentials, learn about the culture, study the internal documentation, and understand how the product works.

🚀 How to use this to your advantage?

The secret isn't just knowing what these acronyms mean, but using them actively. If during an interview for a premium tech role you ask, "How does your PTO policy and Vesting schedule work?", the recruiter will immediately perceive you as a high-level professional, familiar with the global market standards.

The remote job market requires preparation. And having the right vocabulary is the first big step to securing six-figure proposals and standing out among thousands of applicants.

Expert Tip

The Back-End Development Market

The Back-End Development Market: Barriers, Opportunities, and the Path to the Top

Behind every brilliant application, revolutionary artificial intelligence, or successful fintech, there is an invisible and robust ecosystem. Welcome to the Back-End universe.

The Modern Back-End Paradox: Did AI Steal the Jobs?

With the rise of tools like GitHub Copilot and Cursor, many junior developers wonder if the Back-End career is threatened. The short answer is: no. In fact, it has evolved.

Artificial Intelligence has made writing basic "CRUD" (Create, Read, Update, Delete) code trivial. However, the market no longer pays six-figure salaries for writing repetitive code. The global market is actively hunting for Software Engineers—professionals who understand architecture, resilience, latency, and scalability. The Back-End didn't die; the bar was simply raised.

Barriers to Entry: What Separates Juniors from Seniors

Entering Back-End development today requires overcoming technical barriers that go far beyond mastering a programming language (like Java, C#, Go, or Python). Key barriers include:

  • System Design: Knowing how to design a system that supports 100 users is easy. Designing one that handles 1 million requests per second requires deep knowledge of load balancing, caching (Redis/Memcached), and message queues (RabbitMQ/Kafka).
  • Data Complexity: The debate is no longer just "SQL vs. NoSQL". It is about data modeling, replication, sharding, and how to avoid database bottlenecks in distributed systems.
  • Security: With data breaches costing millions, companies require developers to master security practices from day one. Not knowing the vulnerabilities listed by the OWASP Top 10 is a dealbreaker for premium remote roles.
  • DevOps and Cloud Culture: The modern Back-End developer must understand containerization (Docker), orchestration (Kubernetes), and cloud infrastructure (AWS, GCP, Azure).

Golden Opportunities: Where is the Money?

For those who overcome these barriers, the market is a blue ocean of opportunities, especially for US/Global Remote work.

  • Migration to Microservices and Serverless: Corporate giants continue to dismantle legacy monoliths. Professionals who understand the patterns described by Martin Fowler are highly sought after.
  • High-Performance Languages: While traditional languages maintain their corporate strength, the use of Go (Golang) and Rust has skyrocketed for systems requiring massive concurrency and low memory footprint (Green Computing).
  • AI Infrastructure: AI models don't run in a vacuum. There is a massive demand for Back-End engineers proficient in Python and C++ to build data pipelines (MLOps) and the APIs that serve these models in real time.

Success Stories: Architectural Decisions That Changed the Game

True Back-End engineering shines when solving impossible problems. Let's look at real-market examples:

The Discord Case (Migration to Rust): Discord faced latency spikes in its core Read States service, originally written in Go. Because Go's Garbage Collector caused critical millisecond freezes, the team rewrote the service in Rust, completely eliminating latency spikes and supporting trillions of messages with absurd efficiency. This proved the value of choosing the right tool for performance limits.

The Netflix Case (Pioneering Microservices): Netflix transformed a monolithic system that broke under pressure into an architecture of thousands of independently managed microservices. They pioneered the concept of Chaos Engineering, purposely shutting down production servers to ensure their Back-End was resilient to failure.

Practical Tips: How to Land Premium Global Jobs

  1. Master the Fundamentals: Before learning the trendy framework of the month, study data structures, algorithms, and time complexity (Big-O Notation). This is exactly what will be tested in high-level technical interviews (Whiteboard interviews).
  2. Build a Problem-Focused Portfolio: A GitHub repository with a "To-Do List" won't impress anyone. Build an API that handles asynchronous image processing, create a scalable URL shortener, or engineer a messaging system using WebSockets and Redis.
  3. Study Real Cloud Architecture: Get solutions-based certifications (like AWS Certified Developer or Solutions Architect). These serve as a "Seal of Approval" to bypass strict Applicant Tracking Systems (ATS) like Greenhouse or Ashby.
  4. Flawless Technical Communication: According to the Stack Overflow Developer Survey, the highest-paying roles require asynchronous global collaboration. Your code documentation, commit messages, and PR reviews must be pristine and professional.

Verdict: Is a Career in Back-End Worth It?

Absolutely. If you are an analytical person who loves solving complex puzzles and cares about the security and efficiency of things no one sees, the Back-End is your place.

It is a career virtually immune to visual fads. While Front-End libraries change every few years, the fundamentals of relational databases, networks, and operating systems remain the same. It is a rock-solid foundation for a highly lucrative and globalized career.