Sabi raises $50 million to build a baseball cap that reads brain signals and turns imagined words into AI prompts

Sabi, a San Francisco startup building a brain-reading baseball cap for talking to AI without typing or speaking, announced on Friday, Oct. 9, 2026, a $50 million seed round led by Khosla Ventures. Accel, Initialized Capital, former OpenAI chief product officer Kevin Weil, DST Global, Collaborative Fund and Ascend also took part. The company plans to show an early prototype at CES 2027.

Every few years someone promises a hat that reads your mind, and every few years the physics of reading brain signals through skull and hair wins the argument. What's different this time is the pitch: Sabi isn't trying to move a cursor for a patient in a lab, it wants to be the keyboard for AI agents, the thing you use when typing a prompt or talking out loud to your phone feels too slow or too public. Khosla's line about not doing a billion brain surgeries is the whole investment thesis in one sentence, and it's a fair shot at the implant crowd. The caveats are big. Everything here, from the power numbers to the dataset size, is the company's own claim; there's no public accuracy figure for imagined speech yet; and the first real demo is a CES booth more than a year away. A $50 million seed buys a lot of hardware iterations. Whether it buys a cap that understands "draft that email" from a thought, and not a sneeze, is the part nobody can grade yet.

On Friday, 9 October 2026, Sabi announced a $50 million seed round led by Khosla Ventures. Accel, Initialized Capital, Kevin Weil — the former chief product officer at OpenAI — DST Global, Collaborative Fund, and Ascend also participated. A seed round is early venture funding, usually a first institutional check. Those names and the dollar figure are on Sabi’s company release, carried on Finanzwire.

Sabi’s first product looks like an ordinary baseball cap. Sensors inside it read neural signals through hair, without gel, surgery, or direct contact with the scalp. Neural signals are the tiny electrical patterns the brain makes when you think. Each sensor measures between one and five millimeters and is built around Sabi’s custom EEG chip. EEG, electroencephalography, is a way of reading brain activity from outside the head. The sensors are designed to capture signals through hair across a gap of up to five millimeters. Those hardware lines are Sabi’s.

In Sabi’s internal benchmarks, its chip was more than 50 times as power-efficient as the Texas Instruments ADS1299, a widely used EEG front end. A front end is the first chip that amplifies the faint signal. That power number is Sabi’s own lab comparison. It is not an outside test.

The signals are processed by Sabi’s Brain Foundation Model, trained on more than 100,000 hours of labeled non-invasive recordings of participants imagining words and doing mental tasks. Non-invasive means nothing was put inside the skull. Sabi says this is the largest disclosed dataset of its kind. Those dataset lines are Sabi’s.

Sabi describes three planned ways to use the cap. Imagined speech to text: words a person thinks on purpose can show up as writing, without being spoken or typed. Thought to prompt: a trained mental command becomes an instruction for an AI assistant. Intent prediction: the system suggests likely keystrokes or on-screen actions for the user to confirm. Those three modes are Sabi’s product plan. They are not a public accuracy score.

The cap connects wirelessly to a phone or computer, like earbuds. Sabi says neural data is encrypted starting at the sensor, and its system is designed to run inference — the model’s live guess — while the data stays encrypted. The company says it is building controls over when the cap records, which apps get commands, and which actions need confirmation. Those privacy lines are Sabi’s.

Sabi was co-founded by chief executive Rahul Chhabra and chief technology officer Atmadeep Banerjee. Banerjee is co-first author of MindEye, a NeurIPS 2023 paper on decoding viewed images from non-invasive brain recordings. NeurIPS is a major AI research conference. The team includes people from Kernel, Apple, Microsoft, Meta, Adobe, and Nike, plus Stanford neuroscientists. Those names are Sabi’s.

Chhabra said: “AI can write, reason and act, yet we still communicate with it by tapping on keyboards and screens. We are building a faster interface that does not require surgery or a laboratory.” Vinod Khosla, founder of Khosla Ventures, said: “You cannot perform a billion brain surgeries to replace a billion keyboards. Every computing era is defined by its interface. Sabi is building one designed for the age of AI.” Both quotations are on Sabi’s release.

Sabi says the money goes to expanding its neural dataset, finishing its custom chip, manufacturing early devices, and hiring. An early prototype will be shown at CES 2027 in Las Vegas. CES is the big January consumer-electronics show. Sabi also runs an early-access waitlist. WIRED covered an earlier beanie version of the product in April 2026. Those timing lines are Sabi’s and WIRED’s.

In plain terms, Sabi said on Friday that it raised a $50 million seed led by Khosla Ventures to build a baseball cap that reads brain signals through hair and turns imagined words into commands for AI. The company cites its own chip-power and dataset numbers. The first public demo is planned for CES 2027. There is no public accuracy figure yet for imagined speech.