Top Tech Startups in San Francisco, CA in 2027

Effective AI is on a mission to transform the future of work by building AI that tackles complex knowledge tasks. Founded by Abhay Mitra (ex-CTO at Nirvana Insurance) and Kunal Singhal (ex-Meta, Grammarly, and Founding Engineer at Wisdom AI), we’re a small, passionate team based in San Francisco that thrives on collaboration, curiosity, and bold problem-solving. Our culture values ownership, continuous learning, and transparency, giving every team member a chance to make a meaningful impact from day one.

The architectures that power modern AI were designed for language, not for science. They were never built to understand DNA, interpret experiments, or learn the rules that govern living systems. Closing this gap represents one of the defining opportunities of our time. Our team has pioneered advances across frontier AI, including the first models trained with one-million-token context windows, and now scaling toward one billion. We focus on innovations on systems and architecture, because building AI for science demands a fundamentally different foundation. As a first application of this technology engine, we are advancing AI for life, the most complex and consequential domain of all. We are the AI team behind Evo and Evo 2, the generative genomics models used to create real gene-editing tools and the first whole genomes designed entirely by AI. That work demonstrated that AI can create biology, not just analyze it. We are now building multimodal models trained directly on the fabric of biology, enabling faster discovery, deeper understanding, and entirely new capabilities. As we push the frontier of scientific world models, we will build systems hand-in-hand to ensure global biological resilience: rapid detection, rapid response, and rapid countermeasures against emerging threats, both natural and synthetic. Our mission is ambitious: to reimagine what AI can do for science, and to build that future.

Callab AI builds AI voice and text agents for enterprise contact centers. We help companies automate customer conversations while keeping the telephony, CRM systems, and workflows they already rely on. Many contact centers run on established on-premises phone systems. Bringing AI to those environments is an infrastructure challenge as much as a modeling challenge. Our SIP-native telephony stack connects directly to systems such as Cisco CUCM, Avaya, and Mitel, so customers can deploy AI agents without replacing their phone infrastructure. Our platform lets teams build agents around their knowledge and business rules, connect them to tools that complete customer tasks, and supervise conversations in real time. When a conversation needs human judgment, a team member can take over with the context preserved. Use cases include customer support, call routing, appointment scheduling, lead qualification, and outbound campaigns. Backed by Y Combinator, We serve customers across three continents and are expanding in the US. Our work spans enterprise software, AI, and the telecom infrastructure that makes reliable customer service possible. We're building the next generation of contact-center automation. Explore our open roles to help bring it to more businesses.

We have been running a bootstrapped startup ActionableAnalytics.Biz for over a decade. We have an IP unit that incubates new ideas and spins of startups. Currently we are trying to get AGACP off from the ground, as multi agent systems is the future to solve agentic problems.

Hallak & Co. is the company behind O.S.C.A.R.™ Proprietary Operational Execution Infrastructure. O.S.C.A.R.™ establishes ownership, accountability, decision structure, KPIs, reporting and leadership cadence across organizations as growth, AI, automation and new ways of working increase operational complexity. Developed from nearly three decades of firsthand business-building and operating experience, O.S.C.A.R.™ is designed to strengthen how organizations execute across teams. Hallak & Co. is expanding O.S.C.A.R.™ through client organizations and a network of experienced Independent Executives, while building the foundation for a future O.S.C.A.R.™ SaaS platform.