Software Engineer, Backend/Applied ML (Safety & Integrity)
Backend Engineer · Senior · Full Time
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Role
What you'll do.
Character.AI is seeking an experienced Senior Software Engineer specializing in Backend and Applied Machine Learning for Safety & Integrity. The ideal candidate will architect robust backend systems and develop innovative ML solutions to address complex safety challenges in human-to-AI interactions, driving technical leadership in an emerging and critical domain of generative AI technology.
Responsibilities
- Backend System Architecture: Design, develop, and maintain highly scalable, resilient, and performant backend systems that power integrity and safety features for AI interactions
- Machine Learning Solutions: Conceptualize, develop, and deploy machine learning models for content classification, anomaly detection, risk scoring, and generative AI safeguards
- Technical Leadership: Drive long-term technical vision for backend integrity systems, providing strategic guidance and mentorship to engineering team members
- Cross-Functional Collaboration: Work closely with product managers, data scientists, AI researchers, and security teams to define requirements and develop innovative integrity solutions
- System Optimization: Continuously analyze and improve performance, scalability, reliability, and cost-effectiveness of existing integrity platforms and ML models
Qualifications
What we look for.
Technical
Backend Programming
Expert-level proficiency in backend programming languages such as Python, Go, Java, or C++
Machine Learning
Comprehensive understanding of ML lifecycle, including data preparation, feature engineering, model development, validation, and deployment
Distributed Systems
Proven experience designing and operating complex, large-scale, and highly available distributed systems
Education
Academic Background
Bachelor's, Master's, or PhD in Computer Science, Engineering, or related technical field
Experience
Professional Experience
Minimum 8 years of professional software engineering experience, with strong emphasis on backend systems development
Trust & Safety Experience
Demonstrated experience in addressing integrity, trust, or safety challenges, preferably in dedicated Trust & Safety or Integrity engineering teams
Skills
Required
Backend Programming
Proficiency in Python, Go, Java, or C++
Machine Learning
Applied ML techniques for content classification, anomaly detection, and risk assessment
Distributed Systems
Design and implementation of scalable, high-performance backend architectures
Preferred
Open Source Contributions
Nice to haveActive participation in open-source projects related to AI, safety, or machine learning
Research Publications
Nice to haveAcademic publications in fields of AI safety, machine learning, or generative AI
Tech stack
Languages
Frameworks
Databases
Tools
Other
Compensation
Pay and benefits.
Base·USD 150,000 – 300,000
Benefits
Competitive Compensation
Salary range of $150K-$300K with meaningful equity compensation
Equity Participation
Stock options in a rapidly growing AI unicorn with significant market potential
Hybrid Work Model
Flexible work arrangement with options for remote and in-office collaboration
Professional Development
Opportunities for continuous learning, conference attendance, and cutting-edge AI research involvement
Innovation Environment
Work at the forefront of generative AI technology with a mission-driven, fast-growing startup
Process
Interview steps.
- 01
Initial Screening
Technical resume review and initial phone screening with recruiting team
- 02
Technical Assessment
Comprehensive coding challenge focusing on backend systems and machine learning problem-solving
- 03
Technical Interviews
Multiple rounds of in-depth technical interviews covering system design, ML techniques, and problem-solving skills
- 04
Leadership and Culture Interview
Assessment of cross-functional collaboration, technical leadership, and alignment with company values
- 05
Final Executive Interview
Discussion with senior technical leadership about long-term vision and potential impact
Full posting
Original listing.
About the role
We’re looking for a talented and creative Software Engineer to join our Safety Engineering team at Character.AI! In this role, you will be at the forefront of designing, developing, and scaling robust backend systems and leveraging applied machine learning to tackle critical integrity and safety challenges. You will be architecting and implementing innovative solutions in a key role in addressing the unique safety challenges that come with human-to-AI interaction—bringing your technical expertise to the table as we define industry best practices in this emerging space. This is a high-impact role where you will provide technical leadership, drive innovation, and contribute to the core of our platform's trustworthiness.
What you'll do
Architect & Build: Design, develop, and maintain highly scalable, resilient, and performant backend systems that power our integrity and safety features.
Lead Complex Solutions: Lead the technical design and implementation of sophisticated backend solutions for detecting, preventing, and mitigating a wide array of integrity risks. This includes traditional issues (e.g., content classification, spam, etc.) as well as emerging threats related to Generative AI (e.g., misuse of generative models, generation of harmful or biased content, etc).
Apply Machine Learning: Conceptualize, develop, deploy, and iterate on machine learning models and algorithms to address complex integrity challenges. This includes areas like content classification (including AI-generated content), anomaly detection, risk scoring, behavior analysis, and developing safeguards for Generative AI systems (e.g., robust content filtering, bias mitigation techniques, and output monitoring).
Cross-Functional Collaboration: Work closely with product managers, data scientists, AI researchers, security teams, and operations to define requirements, design innovative solutions, and deliver impactful integrity systems, especially for Generative AI products.
Technical Strategy & Roadmap: Drive the long-term technical vision and roadmap for backend integrity systems and applied ML capabilities, with a keen eye on addressing Generative AI safety concerns with an alignment with company objectives.
Mentorship & Leadership: Provide technical guidance and mentorship to other engineers on the team and across the organization, fostering a culture of engineering excellence.
Champion Best Practices: Advocate for and implement best practices in software engineering, distributed systems design, data engineering, and the full lifecycle of ML model development, including specific considerations for the safety and ethics of Generative AI.
System Optimization: Continuously analyze and improve the performance, scalability, reliability, and cost-effectiveness of existing integrity platforms and ML models.
Stay Current: Keep abreast of emerging threats, new technologies, and advancements in backend engineering, distributed systems, the application of machine learning to trust and safety, and the evolving landscape of Generative AI safety research and mitigation techniques.
Who you are
8+ years of professional software engineering experience, with a strong emphasis on backend systems development.
Bachelor's, Master's, or PhD degree in Computer Science, Engineering, or a related technical field.
Proven track record of designing, building, and operating complex, large-scale, and highly available distributed systems.
Expertise in one or more backend programming languages such as Python, Go, Java, or C++.
Hands-on experience in applying machine learning techniques to solve real-world problems, specifically with demonstrable experience in addressing integrity, trust, or safety challenges.
Solid understanding of the machine learning lifecycle, including data gathering and cleaning, feature engineering, model selection, training, validation, A/B testing, deployment, and operational monitoring.
Exceptional problem-solving abilities, with a knack for tackling ambiguous and technically challenging problems.
Proven ability to work in a fast-paced development environment and deliver timely results.
Strong communication, interpersonal, and leadership skills, with the ability to articulate complex technical concepts to diverse audiences.
You will be a great fit if:
You care deeply about Trust & Safety and see it as a value-add to the business
Prior experience in a dedicated Trust & Safety, Integrity, or Risk engineering team.
Contributions to open-source projects or publications in relevant fields.
Experience leading large, cross-cutting technical projects.
About Character.AI
Character.AI empowers people to connect, learn and tell stories through interactive entertainment. Over 20 million people visit Character.AI every month, using our technology to supercharge their creativity and imagination. Our platform lets users engage with tens of millions of characters, enjoy unlimited conversations, and embark on infinite adventures.
In just two years, we achieved unicorn status and were honored as Google Play's AI App of the Year—a testament to our innovative technology and visionary approach.
Join us and be a part of establishing this new entertainment paradigm while shaping the future of Consumer AI!
At Character, we value diversity and welcome applicants from all backgrounds. As an equal opportunity employer, we firmly uphold a non-discrimination policy based on race, religion, national origin, gender, sexual orientation, age, veteran status, or disability. Your unique perspectives are vital to our success.
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