The companies in Sunnyvale are primarily mid-sized to large firms in software development, IT services, and cybersecurity. Notable examples include Synopsys Inc, which provides silicon and systems design solutions, and LinkedIn, a global professional networking platform. Fortinet specializes in computer and network security, while Juniper Networks develops intelligent networking products. Xoriant is a digital engineering firm, and Proofpoint focuses on cybersecurity and compliance solutions.
A common pattern among these companies is their focus on technology infrastructure and digital solutions. Many were founded in the 1990s and early 2000s, indicating a mature technology hub. The presence of companies like Applied Intuition, which supplies vehicle software, and Clover, offering point-of-sale solutions, shows a diverse application of software development across various sectors.
| # | Company | Employees | |||
|---|---|---|---|---|---|
| 1 |
Synopsys Incsynopsys.com
It provides comprehensive silicon and systems design solutions, partnering with customers to enhance R&D capabilities and drive innovation across industries. |
27,809 | |||
| 2 |
LinkedIncareers.linkedin.com
It connects professionals globally, offering services like Talent Solutions, Marketing Solutions, Sales Solutions, and Premium Subscriptions for productivity and success. |
23,635 | |||
| 3 |
Fortinetfortinet.com
Fortinet enables trust in the digital world by protecting people, devices, and data for enterprises, service providers, and government organizations |
16,304 | |||
| 4 |
Juniper Networksjuniper.net
Develops intelligent, agile, and secure networking products and solutions serving global service providers, enterprises, and government organizations worldwide. |
9,059 | |||
| 5 |
Xoriantxoriant.com
Xoriant is a global digital engineering firm that turns imaginative visions into realities, accelerating business outcomes with innovative technology solutions |
5,220 | |||
| 6 |
Proofpointproofpoint.com
A company specializing in cybersecurity and compliance solutions, protecting people across email, web, cloud, and social media channels effectively |
5,200 | |||
| 7 |
Cepheidcepheid.com
Healthcare company pioneering molecular diagnostics with automated systems and tests for a wide range of infections, diseases, and oncology, delivering actionable results Partnered with industry leader for expertise and solutions |
4,675 | |||
| 8 | 2,417 | ||||
| 9 |
Good Powered by BlackBerryblackberry.com
Provider of secure mobile solutions including device management, collaboration apps, and analytics for enterprises and governments worldwide. |
2,065 | |||
| 10 |
Finisar Corporationcoherent.com
Follow us at the provided link for updates and information about our rebranding as Coherent Corp Exciting changes ahead! |
1,709 | |||
| 11 |
Cloverclover.com
Innovative point of sale solutions for small & medium businesses, enhancing customer interactions and creating a seamless commerce operating system Join our team in Sunnyvale, CA! |
1,685 | |||
| 12 |
Applied Intuitionappliedintuition.com
Vehicle software supplier accelerating safe and intelligent machines globally through simulation and validation platforms for automotive, trucking, and construction industries Headquarters in CA |
1,593 | |||
| 13 |
Upworkupwork.com
A global platform connecting businesses with independent talent, unlocking potential through trust-driven collaboration across a wide range of skills |
1,487 | |||
| 14 |
Intermedia Intelligent Communicationsintermedia.com
Cloud communications company providing integrated solutions for voice, video, chat, contact center, email, security, and more, with a focus on exceptional customer service and partner support |
1,381 | |||
| 15 |
Plug and Playplugandplaytechcenter.com
global platform connecting startups, corporations, investors across multiple industries to foster innovation, investment, and collaboration worldwide. |
1,311 | |||
Want more companies than this list?This page shows the largest ones only. Connect to Tamtam to see every company that matches, filter by size, industry or growth, and reach their decision-makers. | |||||
| 16 |
Fujitsu Americasfujitsu.com
Leading provider of IT services and solutions globally, specializing in consulting, systems integration, managed services, cloud services, and server technologies, with a focus on sustainability and innovation |
1,173 | |||
| 17 |
Spansion is Cypress Semiconductorinfineon.com
A leading semiconductor company offering high-performance solutions for embedded systems in automotive, industrial, networking, consumer, and mobile devices worldwide |
1,097 | |||
| 18 |
Illumioillumio.com
Leading ransomware, breach containment; redefining cyberattack containment, operational resilience; AI security graph identifies, contains threats across hybrid multi-cloud environments; stopping attack spread. |
916 | |||
| 19 |
Mellanox Technologies
A leading supplier of high-performance InfiniBand and Ethernet interconnect solutions for servers and storage, accelerating application run time and maximizing business results |
840 | |||
| 20 |
eGain Corporationegain.com
AI-powered knowledge management platform enhancing customer experience and reducing service costs for Fortune 500 clients and government agencies. |
782 | |||
| 21 |
Crestacresta.com
It enhances contact center performance using generative AI for real-time insights, coaching, and tracking agent interactions to improve efficiency. |
727 | |||
| 22 |
Jumio Corporationjumio.com
Provides AI-powered identity intelligence, anchored in biometric authentication and automation, to establish and maintain trust for organizations and fight fraud. |
613 | |||
| 23 |
R.S. Hughes Co., Inc.rshughes.com
Dynamic distributor of industrial supplies, with extensive inventory of products from leading manufacturers Specializing in sales and service solutions for manufacturing companies |
555 | |||
| 24 |
Indium Software - Independent Software Testing Companyindiumsoft.com
Global Independent Software Testing Services Company with a focus on multiple domains, offering on-demand QA services, specialized testing, and innovative frameworks for accelerated testing |
523 | |||
| 25 |
HackerEarthhackerearth.com
Developer assessment software helping companies accurately measure developer skills, improve engineering hires, reduce recruiter screening time, and engage developers in hackathons and coding challenges |
512 | |||
| 26 |
SMARTesmarte.pro
It provides a B2B sales intelligence platform that integrates with sales tools, offering contact insights and enhancing sales workflows for teams. |
473 | |||
| 27 |
ThinkSys Incthinksys.com
An award-winning technology company providing software development, QA, and IT services worldwide, with a focus on customer satisfaction and quality solutions |
453 | |||
| 28 |
Crazy Maple Studiocrazymaplestudios.com
A Bay Area start-up offering mobile gaming, reading, and streaming experiences Users can enjoy interactive stories, write romance, and watch HD content |
414 | |||
| 29 |
Surabhisurabhillc.com
A multifaceted company specializing in healthcare revenue cycle management, medical equipment distribution, and BPO support services with a focus on quality and efficiency |
377 | |||
| 30 |
HCL Unicahcl-software.com
Marketing software for digital transformation, empowering organizations with enterprise marketing solutions for valuable customer relationships and measurable business outcomes |
360 | |||
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How this list is built
Every company on this list has a Tamtam company profile. The industry is the one the company gives on LinkedIn; categories such as SaaS or fintech are classified by Tamtam's AI from the company's website and LinkedIn page; and the headquarters city must match the company's own address. Companies are ranked by the number of employees on LinkedIn, and the list is refreshed every night. Classifications can be wrong, so treat the list as a starting point rather than an official ranking. Last updated Nov 12, 2026.
More company lists in Sunnyvale
- The largest companies in Sunnyvale 165
- SaaS companies in Sunnyvale 42
- Software Development companies in Sunnyvale 41
- AI companies in Sunnyvale 31
- Companies with in-house R&D in Sunnyvale 30
The same list elsewhere in United States
- Multinational companies in the United States 16,197
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- Multinational companies in New York State 2,216
- Multinational companies in Texas 1,418
- Multinational companies in Florida 897
- Multinational companies in Illinois 831
- Multinational companies in Massachusetts 637
- Multinational companies in New Jersey 624
- Multinational companies in Georgia 521
- Multinational companies in Pennsylvania 472
- Multinational companies in Michigan 468
- Multinational companies in Alabama 418
- Multinational companies in Virginia 396
- Multinational companies in Ohio 390
- Multinational companies in North Carolina 358
- Multinational companies in Washington State 288
- Multinational companies in Colorado 228
- Multinational companies in New York 1,836
- Multinational companies in San Francisco 446
- Multinational companies in Houston 402
- Multinational companies in Chicago 366
- Multinational companies in Miami 289
- Multinational companies in Atlanta 252
- Multinational companies in Boston 241