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Sunday (formerly Sunday Robotics) is an American AI robotics company headquartered in [[Mountain View, California]], [[United States]], developing [[humanoid robot]]s for household use. Founded by Stanford PhD roboticists Tony Zhao (CEO) and Cheng Chi (CTO), the company builds the [[MEMO (robot)|Memo]] humanoid robot, a wheeled domestic assistant designed to help with household chores such as laundry folding, table clearing, and beverage preparation. In March 2026, Sunday reached unicorn status with a $1.15 billion valuation following a $165 million Series B funding round.
Sunday was co-founded by Tony Zhao and Cheng Chi, both PhD graduates from [[Stanford University]]'s robotics program. The founders brought deep expertise in imitation learning and robot manipulation, fields critical to teaching robots household tasks from human demonstrations.[1]
The company developed the [[MEMO (robot)|Memo]] humanoid robot as its primary product, choosing a wheeled base rather than bipedal legs for greater balance, lower weight, and reliability in home environments.
In October 2025, Sunday demonstrated Memo's ability to fold piles of socks, handle glassware, and pull a shot of espresso, showcasing the robot's dexterity and task versatility.[2]
On November 19, 2025, Sunday opened applications for the Founding Family Beta program, inviting fifty households to become early adopters of Memo, with the beta launching in late 2026.[3]
In March 2026, Sunday announced it had raised $165 million in Series B funding at a $1.15 billion valuation, reaching unicorn status. The round was aimed at scaling manufacturing and expanding the beta program.[4]
[[MEMO (robot)|Memo]] is Sunday's flagship household humanoid robot.
| Specification | Details |
|---|---|
| Height | 1.7 m (5 ft 7 in) |
| Weight | 77 kg (170 lbs) |
| Horizontal Reach | 0.8 m (2 ft 7 in) |
| Vertical Reach | Up to 2.1 m (6 ft 11 in) |
| Mobility | Wheeled base |
| AI Model | ACT-1 (proprietary) |
| Current Cost (hand-built) | ~$20,000 |
| Target Retail Price | Under $10,000 |
Memo features a rolling base for stability and energy efficiency, with dual arms capable of reaching overhead cabinets and performing floor-level tasks. The robot's design prioritizes practical household functionality over humanoid aesthetics.[1]
As of late 2025, Memo has demonstrated the ability to:
Memo is powered by ACT-1, Sunday's proprietary foundation model built in-house. ACT-1 is trained on demonstration data collected from human operators wearing the Skill Capture Glove, a proprietary data collection device.[2]
The training dataset comprises approximately 10 million chore "episodes" collected from more than 500 homes, representing one of the largest real-world household robotics datasets. This data is used to train the ACT-1 model to generalize across diverse home environments, object types, and task variations.[3]
Sunday's Skill Capture Glove is a wearable data collection device that matches the physical dimensions and capabilities of Memo's hands. "Memory Developers" wear these gloves while performing household tasks, generating paired hand-motion and visual data that is used to train the ACT-1 model. The gloves cost approximately $200 each.[2]
Sunday's approach to robot learning is based on large-scale imitation learning, where the robot learns to replicate human demonstrations rather than being programmed with explicit task instructions. The scale of the data collection effort (10 million episodes from 500+ homes) is designed to capture the enormous variety of household environments and task variations that a domestic robot would encounter.[3]
Sunday's initial go-to-market strategy is a beta program. Starting November 19, 2025, the company accepted applications for fifty households to serve as early adopters, with the beta launching in late 2026. Beta participants will receive hand-built Memo units and provide feedback to improve the robot's capabilities.[3]
Building a single Memo by hand costs approximately $20,000 as of 2025. Sunday has set a target retail price of under $10,000 once the robot is manufactured at scale, positioning it as an accessible consumer product.[3]
| Round | Amount | Valuation | Date |
|---|---|---|---|
| Series B | $165 million | $1.15 billion | March 2026 |