ToolsCompaniesAbout
Company

21st

21st provides a community library of interface components and AI tools for drafting and reviewing application designs. Its products serve developers building and refining user interfaces.

Linked from 21st.dev · checked 30 Oct

Visit 21st.dev
Status
Active
Checked 30 Oct 2026
Y Combinator
Winter 2026
Batch W26
Based in
Unknown
Founded
Unknown
Not confirmed yet
Tools listed
2

Tools from 21st

  • 21st Design Bug Bot

    Review pull requests for UI design issues and suggested fixes

    Coding · Install · Checked

    Five free reviews; then paid AI creditsAfter five successful reviews, use a Builder + AI subscription from $15/month equivalent billed annually. Reviews consume shared AI credits; each repository caps usage at 2,000 credits per month.
  • 21st AI

    Generate and compare several UI component designs from a prompt

    Coding · Sign up · Checked

    From $15/month, billed annuallyBuilder + AI starts at $15/month equivalent on annual billing. Plans include 500, 1,000 or 2,000 monthly credits; 100-credit top-ups cost $5.

From @21st_dev

Recent important posts · launches

Open on X
  • Launch

    21st Wallpapers: free 4K wallpapers for iPhone and Mac

    “Introducing 21st Wallpapers: free 4K wallpapers for your iPhone and Mac Made from 300+ shaders, all built in React Link below ↓”

    @21st_dev · Oct 25View

History

Free account

See 21st’s history

Renames, moves, pivots and launches, dated and sourced. Free with an account.

Momentum

Free account

See 21st’s momentum

Launch traction, hiring and release activity, tracked over time. Free with an account.

Where this comes from

Company website
Product, pricing and policy pages
YC directory mirror
Batch and company name
Social accounts
Accounts the company links, and its posts on X
Human review
Checked by a person
knowledge_base
manual_review

Company facts stay “unknown” until a source confirms them.