Best Open Source Companies in California, United States

Data and AI platform that unifies analytics. Its main site highlights building apps, agents, and AI on your data, with pricing based on pay-as-you-go usage. The platform offers data management, warehousing, engineering, and science capabilities. It facilitates data sharing, governance, and application development. The platform supports business intelligence and database functionalities.

Funding rounds

• Jan 2026Conventional Debt$2B
• Dec 2025Unattributed$5B
• Sep 2025Series K$1B
• Jan 2025Conventional Debt$5.2B

Founders & team

Andy KonwinskiCo-FounderArsalan Tavakoli-ShirajiCo-Founder & SVP of Field EngineeringReynold XinCo-Founder

Investors

Nvidia, Capital One, Andreessen Horowitz, Fidelity Investments, Insight Partners, Tiger Global Management

Tech stack

6SenseAdobe Audience ManagerAmazon AlbAmazon CloudfrontAmazon S3Amazon Ses

Developer of platform for building and managing autonomous agents and workflows. The platform offers tools for developing, deploying, and managing autonomous agents and RAG pipelines. It provides features such as integrations, observability, and the ability to connect to various large language models. The platform supports the creation of AI applications through visual workflows and offers options for publishing and integration with other systems.

Funding rounds

• Mar 2026Seed$30M
• Mar 2025Angel—

Founders & team

John WangCo-Founder

Investors

China Renaissance Capital Investment, HSG, GL Ventures, Bessemer Venture Partners, 5Y Capital, Mizuho Leaguer Investment

Tech stack

Base UiCloudflareCloudflare Browser InsightsCookieyesDiscourseEmber.Js

Developer of open-source platform for building and scaling realtime voice agents. The platform provides APIs and tools for creating applications with voice and video capabilities. It offers infrastructure for managing concurrent calls, turn detection, and integration with telephony systems. The platform supports self-hosting or deployment to a cloud environment.

Funding rounds

• Jan 2026Series C$100M
• Apr 2025Series B$45M
• Mar 2024Series A$22M
• Sep 2022Series A$7.3M

Founders & team

Russell SaCo-Founder & CEODavid ZhaoCo-Founder & CTO

Investors

Altimeter Capital, Redpoint Ventures, Hanabi Capital, Salesforce Ventures, Index Ventures, Boost VC

Tech stack

Apple Icloud MailCloudflareCloudflare Browser InsightsDiscourseEmber.JsGoogle Workspace

Cloud based product analytics tools. Features of the product include user behavior analysis, analyzation of trends, funnels, retention, and cohorts, compatibility, data access, and more. It also provides data retention, supports SSO SAML, exports to data lakes, pricing models, analytics stack, and more.

Funding rounds

• Sep 2025Series E$75M
• Jun 2025Series D$70M
• Jun 2025Series C$10M
• Jun 2021Series B$15M

Founders & team

Tim GlaserCo-Founder & CTOJames HawkinsCo-Founder & CEO

Investors

Google Ventures, Y Combinator, Stripe, Formus Capital, Peak XV Partners, Uncorrelated Ventures

Tech stack

Amazon SesAmazon Web ServicesAmplitudeApple Icloud MailBase UiCloudflare

Developer of a prototype to production connectivity platform for IoT. Its Photon Wi-Fi and the Electron 2G3G cellular are primary prototyping platforms for integrating connectivity into devices. The product is primarily aimed at designers and developers rather than at enterprises.

Funding rounds

• Mar 2025Series C$5M
• Dec 2022Series C$12.2M
• Nov 2021Series C$30M
• Nov 2019Series C$40M

Founders & team

Zach SupallaCo-Founder & CEO

Investors

O'Reilly AlphaTech Ventures, Root Ventures, HAX, Collab Fund, Spark Capital, Qualcomm Ventures

Tech stack

AceAmazon CloudfrontAmazon S3Amazon Web ServicesAmerican ExpressApple Icloud Mail

Cloud based API management and microservices connectivity platform. It operates through RESTful API and is built on NGINX. It inspects and monitors APIs and microservice traffic. It provides ready to deploy plugins and adds functionality to APIs and applications. It also offers the flexibility to run on the cloud of the users choice such as AWS, Azure, Google Cloud. It has clients such as Cisco, GSK, Paypal, etc.

Funding rounds

• Nov 2024Series E—
• Aug 2024Series D$80M
• Dec 2020Series D$100M
• Dec 2018Series C$43M

Founders & team

Marco PalladinoCo-Founder & CTOAugusto MariettiCEO & President

Investors

Andreessen Horowitz, CRV, Index Ventures, Tiger Global Management, GGV Capital, World Innovation Lab

Tech stack

6SenseAdrollAdroll Cmp SystemAlpine.JsAmazon CloudfrontAmazon S3

Provider of visualization and debugging solutions for robotics. It allows users to use customizable layouts for the arrangement of interactive visualizations and understanding the activities of robots. It provides built-in panels for displaying robots in 3D, plotting message values, publishing messages, displaying messages, tracking, and detecting state transitions.

Funding rounds

• Sep 2025Series B$40M
• Oct 2022Series A$15M
• Jan 2022Seed$3.7M

Founders & team

Roman ShtylmanCo-Founder

Investors

Amplify Partners, Eclipse, Boost VC, Bessemer Venture Partners, Amplify, SkyGate Digital

Tech stack

Apple Icloud MailAstroCloudflareCloudflare Browser InsightsDocusaurusEmotion

Open source based NoSQL database platform for enterprises. It offers a distributed NoSQL database optimized for storage with key-value store architecture for real-time web applications. The platform processes transactions, documents, graphs, and vectors for real time operations and decisioning.

Open source based cloud infrastructure visualization platform. It is a software company that provides a tool for organizations to map their infrastructure, highlighting potential attack paths and weak points that could lead to sensitive data exposure. The platform aims to give security teams visibility and focus on the most critical risks. The platform helps organizations improve their security posture by identifying vulnerabilities and prioritizing remediation efforts.

Funding rounds

• Nov 2025Seed$4.2M
• 2025Seed$500K

Founders & team

Alex ChantavyCo-Founder & CEO

Investors

Y Combinator, FundersClub, Phosphor Capital, Transpose Platform

Tech stack

Amazon Web ServicesApple Icloud MailCart FunctionalityFastlyGithub PagesNext.Js

Provider of open-source software to manage data from devices. The platform enables users to collect and control data for servers, PCs, and laptops. Its offering includes inventory management tools, data collaboration tools, monitoring tools, and deployment tools. Offers a subscription-based pricing model.

Funding rounds

• May 2025Series B$27.9M
• Apr 2022Series A$20M
• Jan 2022Seed$5M

Founders & team

Zach WassermanCo-FounderMike McNeilCEO

Investors

CRV, Ten Eleven Ventures, Open Core Ventures, Moonfire, StoneMill Ventures

Tech stack

AceActivecampaignApple Icloud MailBabelBootstrapChart.Js

Developer of open-source cloud-native Postgres designed to create a cloud-native database service for developers. The company's system separates storage and computes to offer autoscaling, branching, and bottomless storage, as well as offer, features such as reliability, auto-backup, and open-source, enabling SaaS companies to enhance engineering velocity and reduce cost.

Founders & team

Stas KelvichCo-FounderHeikki LinnakangasCo-FounderNikita ShamgunovCEO

Investors

M12, Abstract Ventures, General Catalyst, Menlo Ventures, Notable Capital, Founders Fund

Tech stack

Amazon SesAmazon Web ServicesApple Icloud MailCloudflareGoogle Tag ManagerGoogle Workspace

Provider of SaaS-based open-source format for APIs. It offers a platform to update the SDKs and documentation with API changes. It generates the types and networking logic and presents a postman collection, with successful and unsuccessful requests.