Lemon Slice
Category: Foundation Models / LLMs
A generative AI platform building real-time, interactive video foundation models that enable developers to create expressive, talking AI avatars for web and mobile applications. Lemon Slice was founded in 2024. The company is led by Lina Colucci. Based in San Francisco, United States. Team size: 3-10. Total funding raised: $16.0M. Latest round: Seed Round ($10.5M, Dec 2025). Key investors include ["Matrix Partners","Y Combinator","The Chainsmokers","Emmett Shear","Arash Ferdowsi"].
- Founded
- 2024
- Headquarters
- San Francisco, United States
- Team size
- 3-10
- Total funding
- $16.0M
Value proposition
Delivers hyper-realistic AI avatars with sub-second latency (real-time interaction), solving the 'uncanny valley' problem through proprietary models that handle emotional expressiveness and non-verbal cues better than existing solutions.
Products and solutions
["Real-time Interactive Avatar SDK (Web/Mobile)","Video Foundation Model API","Custom Character Generation Engine","Script-to-Video Generation Tool"]
Unique value
Leverages a proprietary 'synthetic data' pipeline (derived from the team's previous startup, Infinity AI) to train video models on massive datasets of perfectly labeled human motion and expression, bypassing the limits of real-world data collection.
Target customer
Developers, Enterprise (Customer Support, Sales), EdTech platforms, and Digital Creators
Industries served
["Generative AI / Synthetic Media","Customer Experience (CX) & Support","Digital Entertainment & Gaming","Education Technology (EdTech)"]
Technology advantage
Achieves 25fps+ rendering directly in-browser with ultra-low latency, enabling natural 'interruptible' conversations. Uses general-purpose diffusion models generating pixels frame-by-frame.
How they differentiate
Real-time, sub-second latency video generation (25fps in-browser) optimized for interruptible, two-way conversation rather than static linear video.
Main competitors
["HeyGen","Synthesia","Tavus","D-ID"]
Key partnerships
["Deepgram","Y Combinator","Matrix Partners","Daily","ElevenLabs"]
Notable customers
["Daily","ElevenLabs"]
Major milestones
["Raised $5M Seed as Infinity AI in Dec 2022","Graduated Y Combinator W24 Batch in Apr 2024","Rebranded to Lemon Slice and launched Real-time SDK in 2025","Raised $10.5M Seed led by Matrix Partners in Dec 2025"]
Growth metrics
110+ customers with 20% WoW growth (reported during YC W24); Real-time rendering at 25fps.
Market positioning
Real-time interactive video infrastructure for developers (API/SDK focus)
Geographic focus
North America, Global
Patents and IP
Proprietary 'Video Foundation Models' and synthetic data generation pipelines
About Lina Colucci
Co-founder of Infinity AI (synthetic data) and Edge Analytics (data science consulting). PhD in Medical Engineering and Medical Physics from Harvard-MIT Health Sciences and Technology. Expert in machine learning and generative video.
Official website: https://lemonslice.com