Full-Time

Research Engineer

AI Safety & Alignment

Updated on 9/3/2026

Character.AI

Character.AI

201-500 employees

Platform to create AI virtual characters

Compensation Overview

$225k - $400k/yr

Redwood City, CA, USA

Hybrid

Three days on-site per week required.

PhD

Category
AI & Machine Learning (1)
Required Skills
LLM
Graphics Processing Unit (GPU)
Kubernetes
Machine Learning
Data Engineering
A/B Testing
Docker
Reinforcement Learning

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Requirements
  • A PhD or equivalent experience in a relevant field such as Computer Science or a related discipline.
  • Ability to write clear and clean production-facing and training code.
  • Experience working with GPUs for training, serving, and debugging.
  • Experience with data pipelines and data infrastructure.
  • Strong understanding of modern machine learning techniques, particularly transformers and reinforcement learning, with a focus on their safety implications.
  • Commitment to the responsible development of AI and solving complex safety challenges.
Responsibilities
  • Develop and implement novel evaluation methodologies and metrics to assess the safety and alignment of large language models.
  • Research and develop techniques for model alignment, value learning, and interpretability.
  • Conduct adversarial testing to proactively uncover potential vulnerabilities and failure modes in models.
  • Analyze and mitigate biases, toxicity, and other harmful behaviors in large language models through reinforcement learning from human feedback and fine-tuning.
  • Collaborate with engineering and product teams to translate safety research into practical, scalable solutions and best practices.
  • Stay current with advances in AI safety research and contribute to the academic community through publications and presentations.
Desired Qualifications
  • Experience with product experimentation and A/B testing.
  • Experience training large models in a distributed setting.
  • Familiarity with machine learning deployment and orchestration using Kubernetes, Docker, and cloud platforms.
  • Experience with explainable AI and interpretability techniques.
  • Research experience in AI safety, alignment, ethics, or a related area.
  • Knowledge of the broader societal and ethical implications of AI, including policy and governance.
  • Publications in relevant academic journals or machine learning conferences.

Character AI builds an AI platform that lets users create and manage virtual characters with distinct personalities for use in games and business applications. The platform enables NPCs and virtual customer service representatives to interact with people in realistic, engaging ways. It works by providing tools to design character personalities, manage their behavior, and deploy them across digital environments, typically via a subscription or licensing model that gives ongoing access and updates. What sets Character AI apart is its focus on both entertainment (gaming) and practical service use, offering a scalable, multi-domain solution with a steady revenue stream rather than a single-market product. The company's goal is to broaden digital interactions by making character-driven experiences more natural and personalized, driving engagement and value for developers and businesses in the growing AI market.

Company Size

201-500

Company Stage

Acquired

Total Funding

$150M

Headquarters

Menlo Park, California

Founded

2021

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Simplify Jobs

Simplify's Take

What believers are saying

  • c.ai Series launched July 2026, opening a new monetizable entertainment format.
  • Age-gated safety changes reduce legal exposure after January 2026 settlement discussions.
  • Character.AI+ pricing and microdramas create multiple paid surfaces beyond free chat.

What critics are saying

  • Kentucky sued in January 2026, alleging teen harm, self-harm, and unsafe recommendations.
  • Google's 2024 licensing deal faces DOJ antitrust scrutiny, threatening commercial flexibility.
  • Under-18 chat bans and model retirements in 2025-2026 alienate core power users fast.

What makes Character.AI unique

  • Character.AI turns every character into persistent IP, not disposable chat sessions.
  • July 2026 c.ai Series adds post-episode character chat, merging entertainment and companionship.
  • Users spent over 950 minutes monthly in 2026, showing unusually sticky engagement.

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Benefits

Flexible Work Hours

Growth & Insights and Company News

Headcount

6 month growth

0%

1 year growth

-4%

2 year growth

-3%
TechCrunch
Jul 9th, 2026
Character.ai launches AI microdramas with interactive twist: users can chat with characters

Character.ai is launching AI-generated microdramas with an interactive twist. Users over 18 can chat with characters from the shows, ask questions, and explore alternative storylines. The company is debuting three series: romance drama "Last Summer," horror show "The Nighttime Game," and survival thriller "Eden Fall." All were created using AI production tools. Character.ai plans to eventually allow users to create their own series. The startup is also testing c.ai FM for audio series and c.ai Reads for fiction creation. This marks Character.ai's latest entertainment-focused feature. In April, it launched Lorebook for world-building and Books, which lets users insert themselves into classic literature. According to Sensor Tower, users spend over 950 minutes monthly on Character.ai.

Yahoo Finance
Jan 13th, 2026
DigitalOcean's AMD-powered cloud platform doubles inference performance for Character.ai, cuts costs 50%

DigitalOcean has announced that its Inference Cloud Platform, powered by AMD Instinct GPUs, is delivering double the production inference throughput for Character.ai, which handles over one billion queries daily. The platform also reduced Character.ai's cost per token by 50% whilst maintaining strict latency requirements. The performance gains resulted from close collaboration between DigitalOcean, Character.ai and AMD to optimise AMD Instinct MI300X and MI325X GPUs specifically for inference workloads. DigitalOcean's platform integrates hardware-aware scheduling and optimised inference runtimes, working with AMD's ROCm software stack and AITER framework. Character.ai's David Brinker said DigitalOcean delivered reliable performance that "unlocked higher sustained throughput and improved economics". The collaboration demonstrates DigitalOcean's strategy of focusing on production outcomes rather than simply GPU availability.

VentureBeat
Jun 12th, 2025
Cloud Collapse: Replit And Llamaindex Knocked Offline By Google Cloud Identity Outage

Join the event trusted by enterprise leaders for nearly two decades. VB Transform brings together the people building real enterprise AI strategy. Learn moreDays after OpenAI and Google Cloud announced a partnership to support the growing use of generative AI platforms, much of the AI-powered web and tools went down due to an outage of the leading cloud providers.Google Cloud Service Platform (GCP) and some Cloudflare services began experiencing issues around 10:00 a.m. PT today, affecting several AI development tools and data storage services, including ChatGPT and Claude, as well as a variety of other AI platforms.We are aware of a service disruption to some Google Cloud services and we are working hard to get you back up and running ASAP.Please view our status dashboard for the latest updates: https://t.co/sT6UxoRK4R — Google Cloud (@googlecloud) June 12, 2025A GCP spokesperson confirmed the outage to VentureBeat, urging users to check its public status dashboard.GCP said affected services include API Gateway, Agent Assist, Cloud Data Fusion, Contact Center AI Platform, Google App Engine, Google BigQuery, Google Cloud Storage, Identity Platform, Speech-to-Text, Text-to-Speech and Vertex AI Search, among other tools. Google’s mobile development platform, Firebase, also went down.VentureBeat staffers had trouble accessing Google Meet, but other Google services on Workspace remained online.A Cloudflare spokesperson told VentureBeat only “a limited number of services at Cloudflare use Google Cloud and were impacted. We expect them to come back shortly

Yahoo Finance
May 23rd, 2025
Us Doj Probing Google Over Character.Ai Deal

The US Justice Department (DOJ) is examining whether Alphabet’s Google violated antitrust regulations through a deal involving the AI technology of Character.AI, a well-known chatbot developer, Bloomberg reported. Regulators are assessing whether the tech giant crafted the agreement to avoid formal merger oversight, sources familiar with the investigation told the publication. In the arrangement made in 2024, Character.AI’s founders returned to Google, and the company obtained a non-exclusive license to utilise the startup’s technology. The raised concerns among regulators about large tech companies suppressing emerging competitors. Google is “always happy to answer any questions from regulators,” Peter Schottenfels, a company spokesperson in an emailed statement to the publication said. “We’re excited that talent from Character.AI has joined the company, but we have no ownership stake and they remain a separate company.” The Justice Department can investigate whether the deal itself undermines competition, even if it did not require formal review, the report said

PYMNTS
May 22nd, 2025
Google’S Character.Ai Deal Reportedly Draws Antitrust Attention

The Department of Justice is reportedly probing whether a Google artificial intelligence (AI) deal violates antitrust law. At issue is Google’s agreement with chatbot maker Character.AI to use that company’s AI technology, Bloomberg News reported Thursday (May 22), citing sources familiar with the matter. According to those sources, regulators recently informed Google they are investigating whether the company designed that agreement to avoid government merger scrutiny