Scale AI, Inc. is an American artificial intelligence infrastructure and software company headquartered in San Francisco, California. Originally focused on data annotation, the company also offers reinforcement learning from human feedback (RLHF) services, large language model (LLM) evaluation, and enterprise software suites for building and deploying AI applications. Its work spans commercial clients, government agencies, and research collaborations, positioning it as a key player in the AI supply chain.
The company was founded in 2016 by Alexandr Wang and Lucy Guo through the Y Combinator accelerator program. It has grown from a data labeling startup into a major AI infrastructure provider, with a valuation exceeding $14 billion by 2024. Scale AI operates subsidiaries for outsourced data labeling, runs a research lab for AI safety, and has partnered with major technology firms and defense organizations.
Founding and Early Years (2016–2019)
Scale was founded in 2016 by Alexandr Wang and Lucy Guo, who had previously worked together at Quora. The company was part of the Y Combinator startup accelerator, which provided initial funding and mentorship. Early investors included Dragoneer Investment Group, Tiger Global Management, and Index Ventures. Guo was fired from the company in 2018, leaving Wang as the sole CEO.
In August 2019, Scale received a $100 million investment from Peter Thiel's Founders Fund, pushing the company's valuation above $1 billion and granting it unicorn status. This funding round marked a turning point, enabling Scale to expand its data annotation services to a broader range of industries, including autonomous vehicles, robotics, and e-commerce.
Growth and Expansion (2019–2025)
Scale contracted with the United States Department of Defense in 2020, beginning a series of government partnerships. In May 2021, Michael Kratsios, former Chief Technology Officer of the United States under the Trump administration, joined Scale as managing director and head of strategy. By July 2021, the company reached a valuation of $7 billion following a financing round led by Greenoaks, Dragoneer, and Tiger Global, driven by increased demand for data labeling across industries.
In January 2022, Scale won a $250 million contract to provide American federal agencies with access to its suite of tools. In February 2022, the company developed its Automated Damage Identification Service in response to the Russian invasion of Ukraine, analyzing satellite imagery to measure building damage and geotagging the results for humanitarian groups. In November 2022, Scale was recognized by Time on its Best Inventions of 2022 list, and the company opened an office in St. Louis.
In January 2023, Scale laid off 20% of its workforce, reflecting broader tech industry adjustments. In May 2023, Scale signed a deal with the US Army's XVIII Airborne Corps, becoming the first AI company to deploy its LLM, known as Donovan, on a classified network. In August 2023, Scale became OpenAI's preferred partner for fine-tuning GPT-3.5, and its services were used to create ChatGPT. That same month, Scale's evaluation platform was used at the DEF CON hacking convention for its first generative AI red team event, testing models from various companies.
In December 2023, Scale contributed to Meta's Purple Llama initiative, a security framework for open generative AI models. In February 2024, the Department of Defense selected Scale to test and evaluate its LLMs for military purposes under a one-year contract. In March 2024, Scale reached a valuation of nearly $13 billion after a funding round led by Accel. In May 2024, the company raised an additional $1 billion from investors including Amazon and Meta Platforms, bringing its valuation to $14 billion.
In August 2024, Scale signed an agreement with the US AI Safety Institute, part of the Department of Commerce's National Institute of Standards and Technology, to collaborate on research, testing, and evaluation of AI models. In December 2024, a former employee sued Scale, alleging wage theft and worker misclassification; a second employee filed a similar suit the following month. In January 2025, several contractors sued Scale, alleging psychological harm from exposure to disturbing content.
In January 2025, The Conversation reported that Scale and Meta had previously collaborated to create and sell Defense Llama, an LLM product for military defense purposes. The company also took out a full-page ad in The Washington Post appealing to President Donald Trump to "win the AI war." Later that month, Scale and the Center for AI Safety released Humanity's Last Exam, a benchmark test for AI systems. Scale also assisted in developing the benchmarks EnigmaEval, MultiChallenge, and MASK.
In February 2025, Scale agreed to a five-year partnership with the Qatari government to improve government services using AI tools and training, including predictive analytics, automation, and advanced data analytics. The deal was signed at the Web Qatar 2025 Summit by Mohammed bin Ali bin Mohammed Al Mannai, Qatar's Minister of Communications and Information Technology. Also in February, Scale became a third-party evaluator of AI models for the US AI Safety Institute.
In March 2025, Scale reached a multimillion-dollar deal with the Department of Defense to develop the Thunderforge project, a major step in US military automation. The project aims to use AI to plan and help execute movements of ships, planes, and other assets, speeding up military decisions in both peace and wartime. The contract was awarded by the Defense Innovation Unit to Scale, Anduril Industries, and Microsoft, with initial use intended for USINDOPACOM and EUCOM.
In April 2025, Scale released Scale Evaluation, a platform for testing LLMs against benchmarks to pinpoint weaknesses and flag where additional training data would improve the model.
Additional Investment from Meta (2025)
On June 10, 2025, it was reported that Meta Platforms had agreed to purchase a 49% non-voting stake in Scale AI for $14.8 billion. The company remained a standalone, independent entity from Meta. As part of the deal, former CEO Alexandr Wang took a top position inside Meta and was replaced by Jason Droege, the company's chief strategy officer and former Uber executive.
Scale Labs
In March 2026, Scale launched Scale Labs, a research division focused on advancing AI safety and evaluation. The lab builds on the company's existing Safety, Evaluation and Alignment Lab, which co-created the Humanity's Last Exam benchmark and conducts research on aligning LLMs with human values.
Operations and Services
Scale AI outsources data labeling through its subsidiaries, Remotasks and Outlier. Remotasks focuses on computer vision and autonomous vehicles, while Outlier specializes in annotating data for large language models. The company also operates an LLM Red Team that conducts human adversarial testing to identify vulnerabilities, biases, and safety risks in AI models. This team has worked with OpenAI, Google DeepMind, and national AI Safety Institutes to evaluate systems against complex threats, including cybersecurity vulnerabilities, jailbreaks, and agentic AI behaviors.
Scale's commercial customers have included Google, Microsoft, Meta, General Motors, OpenAI, and Time. The company also works directly with world governments, including the United States on military-related projects and Qatar on social program efficiency.