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 building complex LLM applications who need a comprehensive orchestration framework

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

LangChain is the most widely adopted framework for building LLM-powered applications and AI agents. It provides abstractions for chains, agents, tools, memory, and retrieval that make it easy to compose complex AI systems. LangGraph, its agent orchestration layer, enables building stateful, multi-actor workflows with human-in-the-loop capabilities. LangSmith provides tracing, evaluation, and monitoring. The LangChain ecosystem is the largest in the AI application development space.

Starting Price

$0Per forever

Starting Price

FreePer monthly

Free Trial

Yes

Free Trial

Free Version

Yes

Free Version

Yes

Website

21st.dev

Website

langchain.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

LangChain

LangChain Expression Language (LCEL)
LangGraph for stateful multi-agent workflows
1000+ integrations
LangSmith observability companion
Python and JavaScript SDKs

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)

LangChain

Pros

Largest ecosystem and community in AI application development
Comprehensive abstractions for chains, agents, tools, and memory
LangSmith provides production-grade tracing and evaluation
LangGraph enables complex stateful multi-actor agent workflows
Extensive integrations with LLM providers, vector stores, and tools

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

LangChain

Data not available

21st.dev or LangChain — 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 LangChain if you wantChoose if you want

Building RAG applications
Multi-agent orchestration with LangGraph
Tool-using conversational agents
Document processing pipelines
Complex chain-of-thought workflows

Compare 21st.dev and LangChain on your own traffic

10KFree traces/mo

500+Models

5 minSetup

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.

Try Respan free

21st.dev vs LangChain (2026)

Overview

Key features

Strengths and tradeoffs

What people are saying

21st.dev or LangChain — which should you choose?

Compare 21st.dev and LangChain on your own traffic

Frequently Asked Questions

Other popular comparisons

21st.dev vs LangChain (2026)

Overview

Key features

Strengths and tradeoffs

What people are saying

21st.dev or LangChain — which should you choose?

Compare 21st.dev and LangChain 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