21st

21st

21st.dev
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About

21st is a developer platform that provides the fastest way to add AI agents directly into applications. The platform offers an SDK that allows developers to define, deploy, and run AI agents with minimal infrastructure setup. Developers can integrate agents using popular frameworks such as Next.js, React, TypeScript, Python, and Node.js. 21st includes built-in features like chat interfaces, session history, tool execution, memory, and real-time streaming responses. The platform also manages backend components such as sandboxed execution environments, authentication, rate limits, and observability. With support for Claude Code and Codex runtimes, developers can build agents that interact with tools, files, and APIs securely. By handling infrastructure and deployment automatically, 21st enables teams to launch production-ready AI agents quickly.

About

Harden AIF is an agent endpoint security platform for AI coding agents. It evaluates supported agent tool calls before execution using the developer’s intent, session context, organisational policy, and the effect of the proposed action. Harden helps protect against destructive commands, unauthorized access, unintended data transfers, secret exposure, privilege misuse, and other unsafe agent actions. Legitimate actions can proceed normally, sensitive data in supported flows can be safely redacted, and actions that fall outside the developer’s intent or authority are blocked before execution. Harden works across popular coding agents and agentic development tools including Claude Code, Codex, Cursor, Antigravity CLI, Kiro, Hermes, and OpenClaw, providing a consistent security layer across the agent ecosystem.

Platforms Supported

Windows
Mac
Linux
Cloud
On-Premises
iPhone
iPad
Android
Chromebook

Platforms Supported

Windows
Mac
Linux
Cloud
On-Premises
iPhone
iPad
Android
Chromebook

Audience

Software developers, startups, and product teams that want a fast and scalable way to build and deploy AI agents inside their applications

Audience

Software engineering teams, security teams, DevSecOps teams, platform engineering teams, AI engineering teams, CISOs, security leaders, and enterprises deploying AI coding agents.

Support

Phone Support
24/7 Live Support
Online

Support

Phone Support
24/7 Live Support
Online

API

Offers API

API

Offers API

Screenshots and Videos

Screenshots and Videos

No images available

Pricing

Free
Free Version
Free Trial

Pricing

No information available.
Free Version
Free Trial

Reviews/Ratings

Overall 0.0 / 5
ease 0.0 / 5
features 0.0 / 5
design 0.0 / 5
support 0.0 / 5

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Reviews/Ratings

Overall 0.0 / 5
ease 0.0 / 5
features 0.0 / 5
design 0.0 / 5
support 0.0 / 5

This software hasn't been reviewed yet. Be the first to provide a review:

Review this Software

Training

Documentation
Webinars
Live Online
In Person

Training

Documentation
Webinars
Live Online
In Person

Company Information

21st.dev
21st.dev/

Company Information

Harden
Founded: 2025
United States
harden.run/

Alternatives

Alternatives

Categories

Categories

Integrations

Antigravity CLI
Claude Code
Cursor
Google Antigravity
Hermes Agent
Kiro
OpenAI Codex
OpenClaw
React
Tailwind CSS
shadcn/ui

Integrations

Antigravity CLI
Claude Code
Cursor
Google Antigravity
Hermes Agent
Kiro
OpenAI Codex
OpenClaw
React
Tailwind CSS
shadcn/ui
Claim 21st and update features and information
Claim 21st and update features and information
Claim Harden and update features and information
Claim Harden and update features and information