The Top Marketplace Startups in YC F25
Y Combinator's Fall 2025 batch includes several marketplace startups taking on specialized verticals, from secondhand goods to robotics data. Here are four worth watching.
SellRaze
Sell your stuff in seconds
SellRaze uses AI to turn a photo into a live listing across multiple marketplaces.
Point your camera at anything, and their AI identifies the item, determines its value, selects the best photos, fills in every detail, and lists it across eBay, Poshmark, Mercari, and Facebook Marketplace automatically.
Once an item sells, SellRaze arranges free pickup from your door.
Over 200,000 users have listed more than 500,000 items on the platform, with 2,500+ items added daily.
CEO Jeff was previously a sneaker reseller who built software to automate limited releases, while co-founder Tyler dropped out of Georgia Tech to work on the company.
Miniswap
The marketplace for tabletop games
Miniswap is a marketplace for the $20B tabletop games industry, starting with Warhammer.
In hobbies as complex as Warhammer, finding what you want on general marketplaces is a pain: filters don't work, products are regularly misidentified, and counterfeit items crowd search results. Miniswap solves this with a catalogue of more than 20,000 unique miniatures.
Using AI, the team built a comprehensive catalogue of every miniature released over the past 25 years with data on every detail buyers and sellers care about.
Since launching four weeks ago, 1,000 gamers have signed up and listed over $40k of inventory.
Co-founder Zak was previously CTO of Hear Me, a mental health app serving over 100k users, and dropped out of his PhD in computer science at Cambridge to start Miniswap.
Co-founder Will worked as a strategic advisor to CEOs at Bridgewater Associates and Pfizer, and dropped out of law school at McGill to join him.
Cortex AI
Large-scale real-world data for robotics
Cortex AI builds the world's most diverse and large-scale real-world workplace robot and egocentric dataset, powering frontier labs developing robotics foundation models and general-purpose robots.
They provide three types of data:
egocentric data from real workplaces, robot trajectories collected from manipulators and humanoids in industry settings, and human-in-the-loop rollouts where remote operators recover robots when they fail.
Through the Cortex Marketplace, workplaces get paid to host data-collection and evaluation sessions, while labs access real-world data.
Founder and CEO Lucas Ngoo was previously co-founder and CTO of Carousell, which he scaled to a $1B+ valuation.
Dome
A unified API for prediction markets
Dome is a unified API for prediction markets like Polymarket and Kalshi, allowing users to trade and analyze data across multiple platforms at once.
The platform unifies prediction markets across platforms into a single interface, matching identical markets across multiple platforms.
Over 50 developers are already building on Dome.
CEO Kurush spent over four years as a founding engineer at Alchemy, helping scale the company from 10 to 250 people and a $10B valuation. He and co-founder Kunal worked closely with Polymarket to build custom infrastructure that helped them scale during the 2024 election.