21st Agents SDK
The 21st Agents SDK is a software development kit designed to simplify the process of adding AI agents to web applications.
Our verdict
Who it's for
The fastest way to integrate AI agents with built-in UI and essential features into your applications.
Pros
- +Accelerates AI agent integration
- +Provides essential features out-of-the-box
- +Compatible with popular web technologies
- +Handles complex aspects like memory and tool use
Key features
- ✓Built-in UI for AI agents
- ✓Chat history management
- ✓Spend limits for AI usage
- ✓Tool execution capabilities
- ✓Memory for contextual conversations
- ✓Observability features
Pricing
| Plan | Price | Billing | Notes |
|---|---|---|---|
| Builder | $6 | month | $6/month billed yearly; Unlimited copies, MCP installs, icons; No monthly AI credits |
| Builder + AI | $15 | month | $15/month billed yearly; 500, 1,000, or 2,000 AI credits/month; Multi-model sketch, code mode |
| Team | $7.5 | month · per seat | $7.50 per seat/month billed yearly; 2–50 seats; Optional AI credits per seat |
| Extra AI credits | $5 | month | +100 for $5; Rolls over; Builder + AI and Team + AI |
Integrations
Slack