Fast Mode

Fast mode is a lightning-quick version of Replit Agent optimized for targeted changes. Get visual tweaks, bug fixes, and reasonable-sized features in 10-60 seconds instead of waiting minutes. Perfect for rapid iteration and pair programming.

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What is Fast Mode?

Fast mode is a specialized Agent experience designed for speed and precision. While the full Agent excels at creating comprehensive applications and implementing complex features, Fast mode focuses on quick, scoped changes that don’t require extensive planning or testing. Think of Fast mode as your pair programming partner for those moments when you need focused changes within your existing app. It’s built to keep you in flow without having to step away from your computer while waiting for longer builds to complete. Fast mode is primarily accessed via the lightning bolt (⚡) icon in the Agent prompt box, and can also be toggled through the Autonomy level control in Agent Tools.

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When to Use Fast Mode

Fast mode is ideal for:

• Visual tweaks: Adjusting colors, spacing, fonts, or layout elements
• Reasonable-sized features: Adding search bars, creating loading states, building form validation, or adding sorting functionality
• Quick fixes: Correcting typos, fixing broken links, or addressing minor bugs
• Rapid iteration: Making a series of focused changes while actively developing
• Scoped updates: When you know exactly what you want changed and don’t need extensive planning

Fast mode may not be suitable for:

• Creating new apps: Fast mode only works within existing apps—use full Agent to start from scratch
• Complex features: Multi-file changes that require architectural decisions
• Large-scale refactoring: Restructuring code across multiple components
• New integrations: Adding third-party APIs or services
• Database schema changes: Modifying data structures or relationships

For these larger tasks, use the full Agent experience which includes comprehensive planning, testing, and validation.

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Features

Fast mode delivers a streamlined development experience with the following capabilities:

• Lightning-fast execution: Complete most changes in 10-60 seconds
• Targeted modifications: Makes only the changes you request without expanding scope
• Cost-effective development: Significantly cheaper than full Agent builds (free during promotional period)
• Real-time pair programming: Stay at your computer and keep building without long waits
• Predictable results: Focused changes mean fewer surprises and more control

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How to Use Fast Mode

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Primary Access: Lightning Bolt Button

The quickest way to toggle Fast mode is using the lightning bolt (⚡) icon in the Agent prompt box:

1. Open Agent in your Replit App
2. Click the ⚡ icon in the prompt box to enable Fast mode
3. Make your request—keep it focused and specific
4. Toggle off when you need full Agent for complex tasks

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Alternative Access: Agent Tools

You can also access Fast mode from Agent Tools: Open the Agent Tools panel and select Fast from the options. Fast mode and Autonomous mode are two distinct approaches: choose Fast when you want quick results while staying at your computer, or Autonomous when you prefer more reliable, longer builds and can step away for a few minutes or more.

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Example Prompts

Good for Fast mode:

• “Change the submit button text from ‘Send’ to ‘Submit Application’”
• “Increase the padding in the card component to 24px”
• “Add email validation to the signup form”
• “Make the sidebar background color darker”
• “Add a search bar to filter the product list”
• “Create a loading spinner when data is fetching”

Use full Agent for:

• “Build a new todo app from scratch”
• “Redesign the entire user dashboard”
• “Add user authentication with Replit Auth”
• “Integrate Stripe payment processing”
• “Add a Linear connector”

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How Fast Mode Works

Fast mode uses a streamlined version of Agent’s AI technology that’s optimized for speed and scoped changes:

1. Focused analysis: Fast mode analyzes only the relevant files for your specific request
2. Direct implementation: Makes changes immediately without extensive planning phases
3. Streamlined execution: Skips comprehensive testing and architecture review for faster results
4. Quick validation: Performs basic checks to ensure changes don’t break existing functionality

This approach allows Fast mode to deliver results up to 5x faster for scoped requests while maintaining quality for the types of focused, well-defined changes it’s designed to handle.

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What’s Different in Fast Mode

To achieve faster speeds, Fast mode disables certain features: Disabled in Fast mode:

• Autonomy levels: Fast mode and Autonomous mode are mutually exclusive—choose Fast for speed or Autonomous for reliability
• App Testing: No automated browser testing
• Architect: No architectural analysis
• High Power models: Uses faster, more efficient models

Still available:

• Web search: Access real-time information
• Other Agent tools: File operations, code editing, image generation, and more

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Pricing

During the promotional period, you’ll see “Free” displayed in your Agent usage summary: After the promotional period ends, Fast mode will offer significant cost savings compared to full Agent builds, with effort-based pricing that charges less for focused, scoped requests.

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Use Cases

Visual iteration: Quickly try different colors, spacing, and layouts while actively designing Reasonable-sized features: Add scoped functionality like search filters, form validation, or loading states Bug fixes: Polish details rapidly before launch

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Comparison: Fast Mode vs. Full Agent

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Tips for Success

• Use Fast mode for iteration and full Agent for new features
• Keep requests specific for the fastest results
• Switch modes when needed: If your change requires multiple files or complex logic, toggle off Fast mode
• Review changes immediately while context is fresh

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Frequently Asked Questions

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Next Steps

Ready to experience faster development with Fast mode?

1. Try Fast mode now: Open any Replit App and enable Fast mode to make your first quick change
2. Learn effective prompting: Review the vibe coding guide for tips on working with AI
3. Explore Agent capabilities: Learn about full Agent mode for building comprehensive features
4. Understand pricing: Review AI billing to understand costs after the promotional period

Start building faster today with Fast mode—completely free for a limited time!