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Polymorph

Polymorph is a YC Winter 2026 (W26) company. Based in San Francisco, CA, USA. Team of 3.

Website (opens in a new tab)

About Polymorph

GPAgent's own fund-neutral profile, written from public information. Updated Oct 4, 2026.

Summary

Polymorph builds personalization infrastructure for consumer and self-serve B2B apps, letting developers integrate AI-driven personalization into user experiences and notifications without building it from scratch. The work it replaces, tailoring content and outreach to individual users at scale, has historically required years of effort and dedicated teams at companies like Facebook and Google. Polymorph packages that capability as developer-ready infrastructure.

Go-to-market

Developer teams at consumer and self-serve apps adopt Polymorph directly, integrating it into their products to drive higher conversion and user retention.

From the Y Combinator listing

How Polymorph describes itself in Y Combinator's public directory.

Personalization infra that improves retention, LTV, and CAC

Polymorph is personalization infra that lets developers use AI to personalize their apps, improving conversion, LTV, and CAC for consumer and self-serve apps. This infra is used to personalize user experiences and notifications, which takes whole orgs years to build at companies like Facebook, TikTok, and Google. They already support over 3.5M users across our customers, with some seeing 3.6x increases in conversion rates after using Polymorph. Users are unique and special, make them feel like it~ The team has extensive experience in the space, having been in senior engineering leadership at Meta Ads, building out large-scale ML infrastructure at Scale AI, and iterating quickly and securely at startups like Gusto, Opal, and Nira.

Facts

Batch
YC Winter 2026 (W26)
Industry
B2B / B2B
Location
San Francisco, CA, USA
Team size
3
Status
Active
Stage
Early
Website
usepolymorph.com (opens in a new tab)

Founders (3)

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