YC Winter 2025 Engineering, Product and Design Startups

Y Combinator's Winter 2025 batch included 25 Engineering, Product and Design startups. Of these, 25 remain active, 0 have been acquired, and 0 have shut down.

• Onlook (4 people) — Cursor for Designers
• Promptless (5 people) — An AI teammate that automatically updates your customer-facing docs
• Macadamia (2 people) — AI Agents for Complex Engineering Projects
• Corsair (2 people) — Connect your users to their apps
• Subtrace (2 people) — Zero code network tracer
• superglue (4 people) — AI that fixes enterprise glue
• a0.dev (3 people) — We make mobile apps using AI.
• Weave (14 people) — AI to understand engineering work
• Adam (4 people) — AI Powered CAD
• hud (15 people) — Platform for building RL environments and evals
• Confident AI (7 people) — The LLM Eval and Observability Platform for AI Quality
• Exla (2 people) — An SDK to run transformer models anywhere
• Dalus (3 people) — AI-Powered Hardware System Design Software
• Cedar (2 people) — Execute the best sales playbook in industry
• TrainLoop (6 people) — Reasoning Fine-Tuning
• Artifact (3 people) — An Collaborative, AI-native IDE for Hardware Engineers
• A1Zap by A1Base (2 people) — The social network layer for AI apps
• Oki (2 people) — The digital home for your personal memories that grows with you
• Mastra (30 people) — The Javascript framework for building AI agents, from the Gatsby devs
• Delineate (20 people) — Agents for Accelerated Clinical Trial Design
• Truffle AI (2 people) — AWS for AI Agents
• Trim (3 people) — A foundation model for physics.
• Stillwind (4 people) — Autonomous Electrical Engineering
• ReJot (2 people) — We turn complex API integrations into drop‑in full‑stack libraries
• Wildcard — AEO/GEO for E-Commerce and Retail