Sandbar raises $23M Series A to develop its AI-powered note-taking ring

Sandbar, the startup founded by former Meta employees Mina Fahmi and Kirak Hong, drew considerable attention last year when it introduced its note-taking wearable, the Stream ring. The company has now secured $23 million in a Series A funding round led by Adjacent and Kindred Ventures.

Sandbar’s smart ring is designed primarily for note-taking, putting it in the same general category as products from Plaud or Omi, rather than health-focused wearables like Oura’s rings. The device includes a microphone that is turned off by default, but it can be activated through a flat, touch-sensitive panel located on the top of the ring. Users can press and hold that panel to record notes, interact with an AI assistant through the linked phone app, and access media controls such as play, pause, track skipping, and volume adjustment.

One notable detail is that the microphone appears to be tuned for close-range use, meaning users need to raise their hand toward their faces to record notes.

Fahmi, who previously worked at startups including CTRL-Labs and Magic Leap, said Sandbar has been developing the ring for more than two years. The company emerged from stealth last year after first testing the product with friends and early adopters.

“The response [to the launch] was a lot warmer than we expected, which is really encouraging and meaningful,” Fahmi said. “A lot of people said they could see themselves wearing this.”

Fahmi said the startup is seeing promising engagement from its early user base. The first batch of Stream ring preorders sold out last year, prompting Sandbar to open a second batch to meet demand. He said some users are interacting with the ring more than 50 times a day for tasks such as planning presentations, trips, or meals.

The startup is planning to begin shipping the smart ring this summer. Sandbar said it is currently focused on improving the app experience and expanding what users can do with the notes they record. The company is also working on a web platform, refining its user interface, and reducing model response latency. Over the longer term, Sandbar wants to support agentic workflows that would allow users to take actions directly from their notes.

Fahmi said the company is also working to bring conversational exchanges into the product, noting that many users ask the AI assistant about notes they did not finish recording.

“Something that we think is necessary is a back-and-forth conversation. Unlike a lot of experiences where you say one command and it’s either transcribed or acted upon, like, via a smart speaker, Stream is really good at iterative tasks which begin, maybe in conversation or editing a note, but hopefully expand to multi-turn conversations, where you’re Claude Coding in your terminal. You are clarifying things [via voice],” Fahmi said.

At the moment, Sandbar’s phone app only works with the Stream ring, though the company said it is considering making the app available to people who do not own the device. The app can also be used independently for note-taking when the ring is charging or if it has been misplaced.

Sandbar currently employs 15 people, with team members who have previously worked at companies such as Amazon, Fitbit, Equinox, Google, and Apple. With the new funding, the startup plans to double the size of its software and machine learning teams and also bring in marketing staff.

The market for hardware note-taking devices is becoming increasingly active. Companies such as Plaud are building devices to record notes during meetings, while Pebble plans to ship a lower-cost $75 ring this year. Other startups, such as Taya, are taking a more premium route by designing their products as jewellery to appeal to a broader audience.

Adjacent’s Nico Wittenborn has prior experience investing in voice-centred startups. While at Insight Venture Partners, he backed Blinkist, the company known for summarising full books. He believes Sandbar’s Stream ring has a better form factor than many competing note-taking devices, and that the motion of lifting a hand to record a note communicates an intent for more private use, unlike some other note-taking products that may capture surrounding conversations.

Wittenborn also said he believes some hardware in the category is designed mainly for “tech bros,” while Sandbar’s form factor makes it better suited for wider mainstream adoption.

The startup had previously raised $13 million from True Ventures last November. Sandbar has now raised a total of $36 million to date.