Scale AI, Inc. is an American artificial intelligence infrastructure and software company headquartered in San Francisco, California. Originally focused on data annotation, the company expanded to offer reinforcement learning from human feedback (RLHF) services, large language model (LLM) evaluation, and enterprise software suites for building and deploying AI applications. In June 2025, Meta Platforms invested $14.8 billion to acquire a 49% non-voting stake in the company, marking one of the largest private investments in AI infrastructure at the time.
The company's research arm, the Safety, Evaluation and Alignment Lab, focuses on evaluating and aligning LLMs, and co-created the benchmark Humanity's Last Exam. Scale AI outsources data labeling through subsidiaries Remotasks, which focuses on Computer vision and autonomous vehicles, and Outlier, which focuses on annotating data for LLMs. The company also operates an LLM Red Team that conducts human adversarial testing to identify vulnerabilities, biases, and safety risks in AI models, working with organizations such as OpenAI, Google DeepMind, and national AI Safety Institutes.
Founding and Early Years (2016-2019)
Scale was founded in 2016 by Alexandr Wang and Lucy Guo through Y Combinator. The pair had previously worked together at Quora. Initial investors included Dragoneer Investment Group, Tiger Global Management, and Index Ventures. Guo was fired from the company in 2018.
In August 2019, after Peter Thiel's Founders Fund made a $100 million investment, Scale's valuation exceeded $1 billion, granting it unicorn status. The company's early focus on data annotation positioned it to benefit from the growing demand for training data in machine learning and deep learning applications.
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 as managing director and head of strategy. By July 2021, Scale reached a valuation of $7 billion after 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 give American federal agencies 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 reports for humanitarian groups. In November 2022, Time recognized Scale 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 amid broader tech industry cutbacks. In May 2023, the company 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 to fine-tune GPT-3.5, with its services used to create ChatGPT. That same month, Scale's evaluation platform was used at DEF CON for the 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 developing 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 Accel led another funding round. In May 2024, Scale raised an additional $1 billion with new investors including Amazon and Meta, bringing its valuation to $14 billion.
Government and Safety Collaborations
In August 2024, Scale signed an agreement with the US AI Safety Institute, controlled by the Department of Commerce's National Institute of Standards and Technology, to collaborate on research, testing, and evaluation of AI models. In February 2025, Scale became a third-party evaluator of AI models for the institute.
In January 2025, The Conversation reported that Scale and Meta had previously teamed up to create and sell Defense Llama, an LLM product with military-style 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 through AI-based 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, the Qatari Minister of Communications and Information Technology.
In March 2025, Scale reached a multimillion-dollar deal with the Department of Defense to develop the Thunderforge project, described as a "major step in U.S. 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 peace and wartime. The contract, awarded by the Defense Innovation Unit to Scale, Anduril Industries, and Microsoft, is intended for initial use with USINDOPACOM and EUCOM.
Legal Challenges and Workforce Issues
In December 2024, a former employee sued Scale, alleging wage theft and worker misclassification. The following month, a second employee filed a similar suit. In January 2025, several contractors sued Scale alleging psychological harm from exposure to disturbing content. These legal challenges highlighted ongoing tensions in the data annotation industry, where workers often face difficult conditions.
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, Scale's chief strategy officer and former Uber executive.
The investment reflected Meta's broader strategy to secure AI infrastructure and data capabilities amid intense competition in generative AI. Meta had previously invested in Scale's May 2024 funding round and collaborated on projects like Defense Llama. The deal gave Meta significant economic exposure to Scale's data annotation and evaluation services without voting control, preserving Scale's operational independence.
Scale Labs and Recent Developments
In March 2026, the company launched Scale Labs, an initiative focused on advancing AI research and development. The launch came amid growing interest in agentic AI and the agentic coding boom, areas where Scale's evaluation and safety expertise are increasingly relevant.
Scale's customers in the commercial sector 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. As of 2025, Scale remained a central player in the AI infrastructure ecosystem, bridging data annotation, model evaluation, and safety testing for both commercial and governmental clients.
Impact and Significance
The Meta investment underscored the strategic importance of data infrastructure in the AI industry. Scale's position at the intersection of data labeling, RLHF, and model evaluation made it a critical partner for major AI developers. The company's work with national AI Safety Institutes and military projects also positioned it as a key player in AI governance and security discussions.
Scale's evolution from a data annotation startup to a comprehensive AI infrastructure provider reflected broader industry trends toward specialized services supporting large language models and transformer architectures. The company's partnerships with OpenAI, Google DeepMind, and Meta demonstrated its central role in the AI ecosystem, while its government contracts highlighted the growing intersection of AI and national security.