Company lists · Data refreshed September 2026

Top 11 Open source AI software companies based in San Francisco, United States

RevenueBase identified 38 open source AI software companies headquartered in San Francisco, United States as of September 2026 and tracks 4,649 professional contacts across them, including 213 with verified work emails and 294 with mobile numbers. Across the United States, San Francisco is the largest hub for this category.

This list covers open source AI software companies headquartered in San Francisco, United States, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 13, 2026.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 13, 2026 86% judged on-target in blind review
38Companies
4,649Contacts tracked
213Verified emails
294Mobile numbers
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The 11 largest open source AI software companies based in San Francisco, United States

Ranked by team size
Top 11 of 38 open source AI software companies based in San Francisco, United States, ranked by team size, largest first. Data refreshed Sep 13, 2026. RevenueBase Smart Search rates how each company's information relates to open source AI software companies: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#CompanyRevenueBase Smart SearchHeadquartersEmployeesContacts
1Partial evidenceSan Francisco, United StatesHQ checked Sep 13, 20265,001-10,0004,170 contacts →

Partial evidence

“Join the AI revolution with Remotasks, where experts can shape the future of AI tools.”

Source: RevenueBase Database · checked Sep 13, 2026
2Indirect evidenceSan Francisco, CA, United StatesHQ checked Sep 13, 202611-50126 contacts →

Indirect evidence

Source: RevenueBase Database · checked Sep 13, 2026
3Strong evidenceSan Francisco, CA, United StatesHQ checked Sep 13, 2026501-1,00054 contacts →

Strong evidence

“An open source machine learning framework that accelerates the path from research prototyping to production deployment.”

Source: RevenueBase Database · checked Sep 13, 2026
4Indirect evidenceSan Francisco, CA, United StatesHQ checked Sep 13, 202611-5052 contacts →

Indirect evidence

“Imbue develops tools that help people think, create, and build.”

Source: RevenueBase Database · checked Sep 13, 2026
5Strong evidenceSan Francisco, United StatesHQ checked Sep 13, 202611-5029 contacts →

Strong evidence

“Essential AI is on a mission to make frontier AI more accessible through an open, collaborative platform.”

Source: RevenueBase Database · checked Sep 13, 2026
6Strong evidenceSan Francisco, CA, United StatesHQ checked Sep 13, 202611-5019 contacts →

Strong evidence

“Promptfoo is the leading open-core platform for AI application security, enabling enterprises to identify and remediate vulnerabilities in LLMs, RAG systems, and AI agents before…”

Source: RevenueBase Database · checked Sep 13, 2026
7Strong evidenceSan Francisco, CA, United StatesHQ checked Sep 13, 20261-1019 contacts →

Strong evidence

“Transluce is an independent research lab that builds open, scalable technology for understanding AI systems and steering them in the public interest.”

Source: RevenueBase Database · checked Sep 13, 2026
8Strong evidenceSan Francisco, CA, United StatesHQ checked Sep 13, 20261-1013 contacts →

Strong evidence

“A 100% open-source company on a mission to democratize how the AI community collaborates on models, datasets, and applications so that the AI of AI has more choices than just a…”

Source: RevenueBase Database · checked Sep 13, 2026
9Partial evidenceSan Francisco, CA, United StatesHQ checked Sep 13, 20261-104 contacts →

Partial evidence

“fast.ai is dedicated to making the power of deep learning accessible to all.”

Source: RevenueBase Database · checked Sep 13, 2026
10Indirect evidenceSan Francisco, CA, United StatesHQ checked Sep 13, 20261-103 contacts →

Indirect evidence

“Khoj is an applied artificial intelligence company.”

Source: RevenueBase Database · checked Sep 13, 2026
11Partial evidenceSan Francisco, CA, United StatesHQ checked Sep 13, 20261-102 contacts →

Partial evidence

“We enable AI at scale.”

Source: RevenueBase Database · checked Sep 13, 2026

Showing 11 of 38 open source AI software companies based in San Francisco, United States

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Open source AI software companies based in San Francisco, United States at a glance

As of Sep 13, 2026
4.6%Verified-email coverage
6.3%Mobile-number coverage
122.3Average contacts per company
1-10Median size (employees)
Sep 13, 2026Page data refreshed

Companies by employee count

1-10
23
11-50
12
501-1,000
1
5,001-10,000
2

Freshness & accuracy

How recently the business emails were verified and the company information checked

Email last verified

Median 15.0d

Company record updated

Median 81.0d

How this list was built

Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among open source AI software companies, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.

Source
The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
What qualifies
Companies headquartered in San Francisco, United States whose own description of what they do matches “open source AI software companies”. Matching reads each company's description, not its industry code or its name.
RevenueBase Smart Search
RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names open source AI software companies), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
What we exclude
Companies whose own description does not clearly place them among open source AI software companies, and records with no verified work email. Companies headquartered outside San Francisco are excluded even when they keep an office there.
Match quality
In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
Ranking
Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
Verification
Every listed company carries at least one verified work email, 213 across the full list. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
Refresh
This page's figures were pulled from the company graph on September 13, 2026. Lists refresh periodically as the graph is re-checked.
Corrections
Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.

Frequently asked

What is RevenueBase Smart Search?

RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names open source AI software companies, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.

How many open source AI software companies are there based in San Francisco, United States?

RevenueBase identified 38 open source AI software companies headquartered in San Francisco, United States as of September 2026, matched on each company's own description of what it does rather than its industry code.

What is the largest company on this list?

Remotasks, headquartered in San Francisco, tops this list with the largest team on record.

Which city in the United States has the most open source AI software companies?

San Francisco leads the United States with 27 headquartered companies, followed by New York (9) and Austin (5).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 213 verified decision-maker contacts tracked across these 38 companies.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 13, 2026.

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About this data

RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase Smart Search, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.