Character.AI

Software Engineer, Applied ML (Discovery, Recommendation & Search)

Character.AI3 months ago
Location

Redwood City, CA

Type

Full Time

Salary

USD 200,000 – 300,000

Level

Senior

Role

ML Engineer

Posted

Dec 18, 2025

Full TimeSenior

The role

Summary

Character.AI is seeking a highly skilled Software Engineer specializing in Applied Machine Learning to enhance their discovery, recommendation, and search systems. The ideal candidate will develop and optimize ML backend infrastructure, working cross-functionally to support the company's innovative AI-powered consumer application.

What you'll do

ML Infrastructure Development: Design and implement applied ML models and infrastructure for discovery surfaces
System Optimization: Optimize existing ML backend systems for recommendation, ranking, and search
Cross-Functional Collaboration: Work with product, data science, and data platform teams to develop innovative AI solutions
Pipeline Management: Develop and maintain end-to-end ML data pipelines and model training infrastructure
Performance Engineering: Ensure high-performance and scalability of ML services and model deployments

What we look for

Technical

Programming LanguagesExpertise in modern typed languages for high-performance service development
Machine LearningStrong understanding of ML frameworks and model optimization techniques
Cloud TechnologiesProficient in cloud infrastructure and distributed computing

Education

Computer Science DegreeB.A.S. in Computer Science or equivalent practical experience

Experience

Industry ExperienceMinimum 5+ years of professional software engineering experience
ML Product DevelopmentExperience shipping intelligent features from conception to production

Skills

Required skills

Cloud InfrastructureExperience with cloud environments (GCP, AWS, or Azure)
ML FrameworksProficiency in PyTorch or TensorFlow
Service DevelopmentBuilding performant services in modern typed languages
Web ServicesExperience with RESTful and gRPC-based web services
CI/CDConfiguring and maintaining continuous integration and deployment pipelines

Nice to have

AI/ML SystemsExperience with production AI/ML systems and services
GPU/TPU OptimizationOptimizing GPU and TPU deployments
Feature StorageWorking with vector databases and feature storage systems
End-to-End ML PipelinesDesigning and implementing full data ingestion to model training pipelines

Compensation & benefits

Salary

USD 200,000 – 300,000 (annual)

Stock options

Available

Benefits

Innovative Work Environment

Opportunity to work at a unicorn AI startup reshaping entertainment

Impact Potential

Chance to make significant contributions from the first week

Diverse and Inclusive Workplace

Commitment to diversity and equal opportunity

Interview process

  1. 1
    Initial Screening — Review of resume and initial qualifications
  2. 2
    Technical Interview — In-depth assessment of ML and software engineering skills
  3. 3
    System Design Round — Evaluation of architectural and infrastructure design capabilities
  4. 4
    Final Interview — Discussion of team fit and long-term potential
Apply for this position

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Character.AI

Character.AI

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Character.AI is an artificial intelligence company that provides a platform for users to create and interact with customizable AI characters. These characters can simulate conversations with a wide range of personalities, from fictional figures to historical persons and original creations. The company's mission is to make advanced conversational AI accessible and engaging for everyone, fostering creativity and exploration through its innovative technology. It operates within the burgeoning market of AI-driven entertainment and interactive digital experiences, offering a unique blend of user-generated content and sophisticated AI models.

Menlo Park, USAFounded 2022character.ai

Tech Stack

Languages
PythonTyped Languages
Frameworks
PyTorchTensorFlow
Databases
Vector Databases
Tools
CI/CDCloud Platforms
Other
gRPCRESTful Services
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On this page

Software Engineer, Applied ML (Discovery, Recommendation & Search) at Character.AI | Scale Engineer