BuiltWith

Gary Brewer created BuiltWith in Australia. ReadWrite reported its launch on August 13, 2007: users could inspect technologies behind websites, including analytics, publishing systems, advertising, content delivery and servers. The service was intended to help developers, researchers and designers understand the tools used to build websites.⁠[1]

In Brewer’s tenth-anniversary account, demand for lists of technology users led to Trends and Pro and a shift from list-size pricing to monthly subscriptions. Andrew Rogers joined in 2012, followed by product and brand rebuilding; Brewer went full-time in 2013. The retrospective said the business had taken no outside investment as of 2017.⁠[2]

BuiltWith announced its acquisition of the website-technology lookup service UnderTheSite.com. It said the original developer could no longer maintain the service and that BuiltWith would take over and continue providing its functionality. The acquisition expanded its presence in website-technology profiling; the announcement did not disclose a price.⁠[3]

In a personal retrospective, Andrew Rogers distinguished free single-site lookup from paid large datasets and described shaping the product through customer interviews. He said he joined for equity under the co-founder title and later became more of an adviser. He also corrected revenue estimates based on confusing cumulative customers with concurrent subscribers.⁠[4]

BuiltWith announced availability through Crunchbase Marketplace, allowing CrunchbaseCrunchbaseCrunchbase is a private-company data and intelligence platform headquartered in San Francisco. It launched in 2007 as TechCrunch’s startup database, and its own company profile lists Michael Arrington as founder. It passed to AOL with TechCrunch in 2010 and was spun out of AOL/Verizon in 2015 with backing from Emergence Capital, with Jager McConnell as CEO; it has since raised more than $100 million and launched Pro, Enterprise, API and Crunchbase News products. Since 2025 it has focused on using AI to forecast private companies’ funding, growth and exits, delivering its data through MCP, APIs and third-party AI platforms.Open the full entry users to view website-technology information within company profiles. The integration combined technology-use data with a company database; it did not establish that Crunchbase had acquired or owned BuiltWith.⁠[5]

BuiltWith announced historical technology data reaching back to 2000, extending coverage that had previously largely begun in 2011. Those earlier dates reflect backfilled historical records and do not mean that the company or product was founded in 2000.⁠[6]

BuiltWith described access for large language models and AI agents, including a streaming-compatible MCP service, machine-readable documentation and a WHOAMI endpoint. WHOAMI exposes account identity, permissions and quota information to help agents use data services within their authorized scope.⁠[7]

BuiltWith introduced AI Maturity, AI Openness, Agent Readiness and AI Visibility scores, assessing externally visible AI tools, access policies, agent interaction and discoverability. It explained that the scores rely on public website signals: a low score does not establish an absence of internal AI use, and openness is not a security judgment.⁠[8]

BuiltWith introduced Acquired and Funded Websites, organizing company domains associated with acquisitions or funding and showing buyers, amounts, rounds and investors where available. Records also include categories, locations and detection dates. A detection date records when the system found an item and should not automatically be treated as the transaction date.⁠[9]

BuiltWith described Website to VAT and Company Numbers, linking public website content to identifiers such as VAT numbers and Australian ABNs or ACNs, with an associated API. It helps identify legal entities behind domains. The company advises checking official registries for tax or compliance use; extracted results are not government certification.⁠[10]

BuiltWith added confidence values from zero to one and high, medium and low labels to technology detections. Factors include repeated signals, recency, parked sites and replacement technologies. Scores indicate evidence strength rather than a uniformly calibrated accuracy rate; some operational metadata uses a fixed midpoint value.⁠[11]

BuiltWith introduced Primary Business, assigning websites a category representing their main products or services. It described AI-assisted classification using public content, keywords, page titles and descriptions, company names and redirects, rather than inferring an industry solely from a domain-name string.⁠[12]

BuiltWith offers free individual website lookups alongside paid list filtering, market research and data exports. Its FAQ says it indexes the public web to collect technology data. The Domain API provides current and historical website technologies and metadata in formats including JSON, XML, CSV and XLSX, subject to account authorization. Such records describe externally observable technology rather than access to internal corporate systems.⁠[13][14]

As checked in November 2026, Crunchbase’s help page lists BuiltWith as a Data Boost provider for current and former website technologies, technology categories, active counts and monthly changes. Users can combine technology filters with company criteria such as funding. The help page’s 2026 update date reflects documentation maintenance rather than the start of the partnership.⁠[15]

BuiltWith is operated by Australia’s BuiltWith Pty Ltd and is headquartered in Sydney. Its official website lists Gary Brewer and Andrew Rogers as co-founders. The company accepts website-removal requests from domain owners, using a verification file or another ownership-confirmation process. It describes technology profiles as derived from publicly accessible website code.⁠[16][17]