Best AI Agent Building Platforms in 2025: A Complete Guide
AI agents are transforming how businesses operate, handling everything from customer support and data analysis to content creation and complex workflow automation. As we move through 2025, the technology has matured significantly, with platforms offering increasingly sophisticated capabilities for building and deploying AI agents.
If you're looking to implement AI agents in your business, you've likely encountered challenges like:
- Complex interfaces requiring technical expertise
- Limited pre-built actions and templates
- High costs for deployment and scaling
- Insufficient control over agent behavior
- Integration difficulties with existing tools
This guide will help you navigate the top AI agent building platforms available in 2025, comparing their features, pricing, and ideal use cases.
TLDR
If you only have 30 seconds, here's what you need to know:
- Best Overall: Relay.app offers the most user-friendly experience with powerful built-in capabilities
- Best for Technical Users: Gumloop provides advanced customization and complex workflows
- Best for Personal Tasks: Lindy.ai excels at daily task management and email handling
- Best for Integrations: Zapier offers the most extensive app connectivity
- Best Open Source: n8n provides full customization and self-hosting options
Top 7 AI Agent Building Platforms
1. Relay.app
⭐ G2: 5.0 (60+ reviews) 🏆 Best for: Easy-to-use AI agent building with extensive pre-built capabilities
What Sets It Apart
Relay.app has revolutionized AI agent building by making it accessible to non-technical users while maintaining powerful capabilities. Its visual interface and pre-built actions let anyone create sophisticated AI agents without coding.
Pros
- Incredibly intuitive interface requiring no technical knowledge
- Extensive library of pre-built AI actions and templates
- Powerful human-in-the-loop capabilities for controlled automation
- Built-in AI credits system with no external API requirements
- Visual workflow builder for creating sophisticated agent behaviors
- Seamless integration with major AI models (GPT-4, Claude 3.5 Sonnet, Gemini)
- Smart templates for common agent use cases
- Flexible approval steps for maintaining control
Cons
- Growing but still limited integration library
- Some advanced features restricted to higher tiers
Pricing
- Free Tier: 200 steps and 500 AI credits monthly
- Professional: $9/month
- Team: $59/month
- Enterprise: Custom pricing
2. Gumloop
⭐ G2: Rising platform (limited reviews) 🏆 Best for: Advanced AI agent development with powerful customization
What Sets It Apart
Gumloop excels in providing programming-like functionality in a no-code environment, enabling the creation of highly sophisticated AI agents with complex behaviors.
Pros
- Advanced AI agent customization options
- Extensive pre-built nodes for complex actions
- Programming-like functionality (loops, subflows)
- Flexible AI model integration
- Strong technical capabilities
- Robust error handling
Cons
- Steeper learning curve
- Complex setup process
- Requires technical expertise
Pricing
- Custom pricing based on needs
- Free trial available
3. Lindy.ai
⭐ G2: New platform (limited reviews) 🏆 Best for: Personal task management and email automation
What Sets It Apart
Lindy.ai specializes in creating AI agents that handle daily tasks with a more human-like approach, excelling in email management and calendar scheduling.
Pros
- Natural language interface for task management
- Strong calendar and email capabilities
- Support for over 3,000 integrations
- Built-in AI model switching
- Human-in-the-loop features
- Simple knowledge base integration
Cons
- Limited workflow logic options
- Requires custom prompts for AI actions
- Basic workflow customization
Pricing
- Free Tier: 400 Tasks and 1M character knowledge base
- Pro: $29.99/month
- Enterprise: Custom pricing
4. Zapier
⭐ G2: 4.5 (1,300+ reviews) 🏆 Best for: Integration-focused AI agent deployment
What Sets It Apart
Zapier combines its massive integration library with AI capabilities, making it ideal for connecting AI agents with existing business tools.
Pros
- Over 7,000+ app integrations
- Strong reliability and support
- Recent AI feature additions
- Extensive template library
- Robust testing capabilities
Cons
- Limited native AI capabilities
- Higher pricing for advanced features
- Requires external AI service integration
Pricing
- Free Tier: 100 tasks per month
- Professional: $19.99/month
- Team: $69/month
- Enterprise: Custom pricing
5. n8n
⭐ G2: 4.6 (50+ reviews) 🏆 Best for: Self-hosted AI agent deployment with full control
What Sets It Apart
As an open-source platform, n8n offers unparalleled customization and control over AI agent deployment and data.
Pros
- Open-source platform
- Self-hosting option
- Extensive customization
- Full control over deployment
- Active community
- Strong security features
Cons
- Requires technical expertise
- Complex setup process
- Limited built-in AI features
Pricing
- Free: Self-hosted version
- Starter: €20/month
- Business: Custom pricing
- Enterprise: Custom pricing
6. Relevance.ai
⭐ G2: New platform (limited reviews) 🏆 Best for: Knowledge-intensive AI agents
What Sets It Apart
Relevance.ai specializes in creating AI agents that leverage large knowledge bases and vector search capabilities.
Pros
- Strong vector search capabilities
- Advanced embedding model support
- Good knowledge base integration
- Real-time indexing features
- Comprehensive analytics
Cons
- Complex setup requirements
- Limited pre-built actions
- Higher technical barrier
Pricing
- Custom pricing based on usage
- Free trial available
7. Stack AI
⭐ G2: 4.3 (3 reviews) 🏆 Best for: Enterprise AI agent deployment
What Sets It Apart
Stack AI focuses on enterprise-grade AI agent deployment with strong security and monitoring capabilities.
Pros
- Robust monitoring and analytics
- Strong security features
- Advanced deployment options
- Comprehensive audit logging
- Enterprise-grade controls
Cons
- Complex interface
- Steeper learning curve
- Higher pricing
- Limited templates
Pricing
- Free Tier: 100 runs monthly
- Starter: $139/month
- Team: $699/month
- Enterprise: Custom pricing
Making Your Choice
When selecting an AI agent building platform, consider these key factors:
- Technical Expertise
- Non-technical teams: Choose Relay.app or Lindy.ai
- Technical teams: Consider Gumloop, n8n, or Stack AI
- Use Case
- General automation: Relay.app or Zapier
- Personal task management: Lindy.ai
- Complex workflows: Gumloop or Stack AI
- Knowledge-intensive: Relevance.ai
- Integration Needs
- Maximum integrations: Zapier
- Built-in AI actions: Relay.app
- Custom integrations: n8n or Gumloop
- Deployment Requirements
- Cloud-based: Most platforms
- Self-hosted: n8n
- Enterprise security: Stack AI
- Budget Considerations
- Best value: Relay.app
- Enterprise-grade: Stack AI or Gumloop
- Open-source: n8n
Final Thoughts
The AI agent building landscape has evolved significantly in 2025, with platforms catering to different needs and technical capabilities. Relay.app leads the pack with its combination of ease of use and powerful features, while others excel in specific areas like technical customization (Gumloop) or integration capabilities (Zapier).
For most users, especially those new to AI agent building, Relay.app provides the best balance of capabilities and usability. However, technical teams might prefer Gumloop's advanced features, while enterprises might lean toward Stack AI's security features or n8n's self-hosting capabilities.
Remember to start with a proof of concept on your chosen platform to ensure it meets your specific needs before committing to a full implementation.
