
Arthur
Founded Year
2018Stage
Series B | AliveTotal Raised
$60.3MValuation
$0000Last Raised
$42M | 3 yrs agoMosaic Score The Mosaic Score is an algorithm that measures the overall financial health and market potential of private companies.
+83 points in the past 30 days
About Arthur
Arthur focuses on artificial intelligence (AI) performance monitoring and management within the machine learning operations (MLOps) sector. It offers solutions for deploying, monitoring, and optimizing machine learning models, ensuring scalability, security, and compliance for enterprise use. Its products include tools for evaluating large language models (LLMs), providing a firewall for LLMs, and enhancing AI model observability. It was founded in 2018 and is based in New York, New York.
Loading...
Arthur's Product Videos
ESPs containing Arthur
The ESP matrix leverages data and analyst insight to identify and rank leading companies in a given technology landscape.
The AI security market provides specialized solutions designed to protect machine learning models, algorithms, and AI applications from AI-specific threats including adversarial attacks, data poisoning, model evasion, backdoor injections, prompt injection, and model theft. These vendors offer products spanning the entire AI lifecycle, including secure model development frameworks, runtime protecti…
Arthur named as Challenger among 15 other companies, including Chainguard, Lakera, and Patronus AI.
Arthur's Products & Differentiators
Model Monitoring & Performance Metrics
Arthur is the only AI performance solution that supports model types including multi-class and regressions, allowing you to measure and optimize all model types in one place. Through hotspots, you can drive actionable insights by automatically finding segments of the population where your model is underperforming; help you find unknown unknowns. Give team members across MLOps and data science the ability to segment the data your model sees in real time to understand model performance, data drift, and feature importance.
Loading...
Research containing Arthur
Get data-driven expert analysis from the CB Insights Intelligence Unit.
CB Insights Intelligence Analysts have mentioned Arthur in 4 CB Insights research briefs, most recently on Nov 7, 2024.

Oct 13, 2023
The open-source AI development market map
Sep 29, 2023
The machine learning operations (MLOps) market mapExpert Collections containing Arthur
Expert Collections are analyst-curated lists that highlight the companies you need to know in the most important technology spaces.
Arthur is included in 5 Expert Collections, including HR Tech.
HR Tech
6,137 items
The HR tech collection includes software vendors that enable companies to develop, hire, manage, and pay their workforces. Focus areas include benefits, compensation, engagement, EORs & PEOs, HRIS & HRMS, learning & development, payroll, talent acquisition, and talent management.
AI 100 (All Winners 2018-2025)
200 items
The winners of the 4th annual CB Insights AI 100.
Cybersecurity
11,029 items
These companies protect organizations from digital threats.
Generative AI
2,841 items
Companies working on generative AI applications and infrastructure.
Artificial Intelligence
10,402 items
Arthur Patents
Arthur has filed 2 patents.
The 3 most popular patent topics include:
- classification algorithms
- machine learning
- artificial neural networks

Application Date | Grant Date | Title | Related Topics | Status |
---|---|---|---|---|
12/9/2020 | 3/5/2024 | Machine learning, Numerical climate and weather models, Climate modeling, Data management, Classification algorithms | Grant |
Application Date | 12/9/2020 |
---|---|
Grant Date | 3/5/2024 |
Title | |
Related Topics | Machine learning, Numerical climate and weather models, Climate modeling, Data management, Classification algorithms |
Status | Grant |
Latest Arthur News
Apr 1, 2025
Experiment. Scale. AI is evolving fast—but making it work at scale remains a challenge. Today, Arthur is launching the Arthur Engine, the first open-source, real-time AI evaluation engine designed to help teams monitor, debug, and improve Generative AI and traditional ML models. No black-box monitoring. No third-party dependencies. No data privacy risks. All for free. Why Real-Time AI Evaluation Matters in 2025 As AI adoption grows, so do its risks. Without real-time evaluation, organizations face: Data leaks— 8.5% of employee prompts contain sensitive data (Harmonic Security). Model degradation— AI models drift over time without ongoing monitoring. Debugging nightmares – Slow iteration cycles lead to poor model performance. The Arthur Engine solves these challenges by providing instant visibility, real-time guardrails, and on-the-fly model optimization—right inside your own environment. “AI is moving fast, and we need to ensure it moves in the right direction. Open-sourcing the Arthur Engine puts powerful AI evaluation tools into the hands of developers, researchers, and builders worldwide.” — Ashley Nader, Lead AI PM at Arthur What Makes Arthur Engine Different? Unlike traditional AI monitoring tools, Arthur Engine runs locally—preserving data sovereignty and eliminating compliance risks. Real-Time AI Evaluation – Instantly detect failures before they impact production. Active Guardrails – Intervene in real-time to prevent hallucinations and bad outputs. Customizable Metrics – Tailor evaluations to your specific AI use case. Privacy-Preserving & Secure – Keep all data inside your infrastructure. Works Across All Models – Supports GPT, Claude, Gemini, open weights models, and traditional ML. “By open-sourcing Arthur Engine, we’re making AI trust and safety accessible to all developers—allowing them to safeguard AI systems with fully customizable, high-performance monitoring tools.” — Cherie Xu, Technical Lead, Machine Learning at Arthur AI Evaluation, Built for the Future The Arthur Engine is part of Arthur’s broader AI performance monitoring suite, designed to help organizations: Validate AI outputs in real time Detect performance shifts before they become problems Ensure regulatory compliance and explainability This open-source release marks a new standard in AI transparency, security, and performance monitoring. Explore Arthur Engine on GitHub Join the waitlist for the new Arthur Platform AI is reshaping the world—let’s make sure it performs the way it should. PR Newswire PR Newswire empowers communicators to identify and engage with key influencers, craft and distribute meaningful stories, and measure the financial impact of their efforts. Cision is a leading global provider of earned media software and services to public relations and marketing communications professionals. previous post
Arthur Frequently Asked Questions (FAQ)
When was Arthur founded?
Arthur was founded in 2018.
Where is Arthur's headquarters?
Arthur's headquarters is located at 140 Crosby Street, New York.
What is Arthur's latest funding round?
Arthur's latest funding round is Series B.
How much did Arthur raise?
Arthur raised a total of $60.3M.
Who are the investors of Arthur?
Investors of Arthur include Acrew Capital, BAM Elevate, Ashley Mayer, Theresia Gouw, Greycroft and 10 more.
Who are Arthur's competitors?
Competitors of Arthur include Predibase, NannyML, 2021.AI, Arize, WhyLabs and 7 more.
What products does Arthur offer?
Arthur's products include Model Monitoring & Performance Metrics and 3 more.
Who are Arthur's customers?
Customers of Arthur include Humana.
Loading...
Compare Arthur to Competitors

Fiddler focuses on artificial intelligence (AI) observability and responsible AI governance in the technology sector. The company provides services such as monitoring, explainable AI, and analytics to support the performance and integrity of machine learning models and large language models. Fiddler serves sectors that need AI governance and risk management, including government and financial services. It was founded in 2018 and is based in Palo Alto, California.

Arize provides tools for AI observability and LLM evaluation within the machine learning and artificial intelligence sectors. The company offers a platform for monitoring, diagnosing, and improving the performance of AI models and applications in production. Arize's tools are based on open-source standards and can integrate with existing AI infrastructure. It was founded in 2020 and is based in Mill Valley, California.

2021.AI focuses on the development and governance of artificial intelligence platforms in the enterprise AI sector. The company's key offering is the GRACE AI Platform, which centralizes AI operations and facilitates management and governance. 2021.AI serves sectors including legal, finance, software and tech, manufacturing, life sciences, transportation, and the public sector. It was founded in 2016 and is based in Copenhagen, Denmark.

Comet focuses on machine learning and operates in the technology sector. The company offers a platform that integrates with existing infrastructure and tools to manage, visualize, and optimize machine learning models. It includes tracking code, hyperparameters, metrics, and more for training runs, as well as monitoring the performance of models in production. It was founded in 2017 and is based in New York, New York.
Gantry focuses on providing observability, analytics, and evaluation tools for AI-powered products within the machine learning industry. The company offers services that enable users to capture and analyze AI product data, monitor model performance, and improve models using user feedback. Gantry's solutions cater to AI-first companies seeking to enhance their machine learning systems with data analysis and performance monitoring capabilities. It was founded in 2020 and is based in San Francisco, California.
Censius is a company focused on AI observability, operating within the artificial intelligence and machine learning industry. The company offers a platform that provides automated monitoring, analysis, and explanation of AI models, enabling businesses to optimize their AI performance and reliability. Its services primarily cater to the needs of machine learning engineers, data scientists, and business stakeholders. It was founded in 2020 and is based in Austin, Texas.
Loading...