Overview

Rating

10.0 / 10

Rating

Best For

React developers and AI app builders who want shadcn/ui-quality components and emerging agent deployment infrastructure

Best For

Developers deploying long-running AI agents

Product Summary

21st.dev is the largest React component registry for the agentic internet — an open-source, community-driven marketplace of shadcn/ui-based React + Tailwind components, blocks, and hooks. 1.4M developers (200K MAU), pivoting into a full agent deployment SDK.

Product Summary

Vercel for background agents — hosting and deployment platform for long-running AI agents with sandboxed compute, scheduling, and message streaming.

Starting Price

$0Per forever

Starting Price

Contact for pricing

Free Trial

Yes

Free Trial

Yes

Free Version

Yes

Free Version

Website

21st.dev

Website

terminaluse.com

Key features

Core capabilities each platform advertises.

21st.dev

Largest React component registry — shadcn/ui + Tailwind based
Open-source and community-driven — npm-like CLI install
Components, blocks, hooks, and full marketing/app templates
AI Agent Registry pivoting toward full agent deployment SDK
200K monthly actives, 1.4M+ developers using it

Terminal Use

Agent hosting & deployment
Sandboxed compute
Scheduling
Message streaming
Long-running agent support

Strengths and tradeoffs

What each tool does well, and the limitations to keep in mind.

21st.dev

Pros

Largest registry of high-quality, free shadcn/ui components
Smooth React + Next.js integration
Active community contribution model
Strong fit for AI-driven workflows
YC-backed with credible pivot toward agent infrastructure

Cons

Quality varies across community-contributed components
Pricing for the agent SDK side is still unclear
shadcn/ui-only — limited if your stack uses a different UI kit
Newer than incumbent component libraries (MUI, Chakra)

Terminal Use

Pros

Massive M funding provides significant runway compared to competitors in the space
All three founders have directly relevant Palantir experience building agent infrastructure at enterprise scale
Framework-agnostic design with Claude SDK, Codex SDK, and Vercel AI SDK adapters avoids vendor lock-in
Filesystem-as-primitive architecture is a genuinely novel approach solving real stateful agent problems
Strong developer experience with CLI-first design, git-native versioning, and markdown scenario testing

Cons

What people are saying

21st.dev

Esme PatelProduct Hunt

Saves so much time — broad set of high-quality, free components, including 3D. Smooth React and Next.js integration.

Read full review

Terminal Use

Data not available

21st.dev or Terminal Use — which should you choose?

Choose 21st.dev if you wantChoose if you want

Rapid React + Tailwind UI prototyping for AI apps
shadcn/ui component discovery and installation
Marketing site assembly from pre-built blocks
AI-generated dashboards and chart UIs
Future: agent-runtime deployment via 21st SDK

Choose Terminal Use if you wantChoose if you want

Agent deployment
Background agent hosting
Scheduled agent tasks
Production agent infrastructure

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500+Models

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Respan lets you trace LLM and agent calls across any model or framework, A/B test prompts on production traffic, and route requests across 500+ models through one gateway.

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21st.dev vs Terminal Use (2026)

Overview

Key features

Strengths and tradeoffs

What people are saying

21st.dev or Terminal Use — which should you choose?

Compare 21st.dev and Terminal Use on your own traffic

Frequently Asked Questions

Other popular comparisons

21st.dev vs Terminal Use (2026)

Overview

Key features

Strengths and tradeoffs

What people are saying

21st.dev or Terminal Use — which should you choose?

Compare 21st.dev and Terminal Use on your own traffic

Frequently Asked Questions

What is an AI agent framework?

Do I need a framework or can I build agents with raw API calls?

Which agent framework should I choose?

Other popular comparisons