Now Live: Multi-Model Routing via Gemini 2.5 Flash

Generate Production-Ready Pages
From a Prompt

FastApp is a state-of-the-art AI page design and code generator. Transpile natural language specifications into deployment-ready HTML structures, styling, and sections in real time.

FastApp Sandbox v1.0.4
Agent Idle
Describe the page you want to generate:
Try suggestion: "Modern portfolio page for a ma..."
4 AI Providers
Gemini · Claude · GPT · OpenRouter
9 Page Templates
Dashboard · Landing · Pricing · Billing...
Complete Pipeline
Plan → Generate → Validate → Preview
Full Version Control
Track edits and restore versions easily
Pipeline Architecture

A production-grade AI compiler pipeline

FastApp orchestrates five distinct engine layers to guarantee perfect structures, gorgeous layouts, and fast loading.

Engine Stage: Prompt

PromptNatural Language Input

Client input is parsed, structured, and normalized. We extract intent, page structure requests, theme specifications, and framework desires.

Key Processes

LLM Router matching to optimal model provider
Prompt safety screening & theme alignment
Tokens & system parameters injection
[stage_prompt] compiling successfully...100% telemetry healthy
Capabilities

Engineered for developer productivity

FastApp packages robust full-stack developer features into a seamless AI workflow. No compromise on quality or control.

Core Engine

AI Planning Engine

FastApp constructs a layout blueprint first. This JSON representation maps page types, global typography options, color variables, component lists, and databases before code generation.

"pageType": "SaaS Dashboard",
"theme": "Dashboard Dark",
"components": ["Navbar", "MetricGrid", "SSEStream"]

Multi-Model Support

Intelligent router queries Gemini 2.5 Flash, OpenAI GPT-4o, Claude 3.5 Sonnet, or OpenRouter based on generation phase to minimize costs and maximize layout speeds.

Planner complete0.2s
Streaming React markup...1.4s
AST validation layerwaiting
CDN edge deploymentwaiting

Real-Time Streaming

FastApp uses Server-Sent Events (SSE) to stream design logs, component code, AST repair events, and deploy state directly to the client browser.

AI-Powered Iteration

Iterate and edit any section of your generated webpage using natural language instructions. Plan-diffing accurately patches changes without rebuilding everything.

Complete Version History

Every single modification step is versioned and safely recorded in the database. Roll back to any design, theme choice, or layout with a single click.

Edge Published

One-Click Edge Deployment

Immediately push generated layouts to FastApp edge servers. Get a custom public URL configured instantly, with code previews and easy HTML/ZIP downloads.

Curated Template Blueprints

Get running in seconds with standard layout options. FastApp structures beautiful templates matching SaaS platforms, portfolios, AI startups, CRM tools, and analytics.

Centralized Project Workspace

Easily manage all generated projects, deployments, and versions in an organized dashboard workspace. Features simple metadata editing, searching, and deleting.

Templates

Pre-configured layouts, ready to stream

Choose a starting blueprint or start from scratch. FastApp shapes clean modular React markup tailored to your target industry.

Analytics

SaaS Dashboard

Comprehensive operations console with interactive grids, sidebar, usage graphs, and dark mode configuration.

Metrics GridServer-Sent FeedActivity Graph
Landing Page

AI Startup

Stunning product introduction showcase with glowing buttons, typing simulations, bento elements, and CTA pipelines.

Bento Feature GridPricing TableWorkflow Cards
Personal

Portfolio

Clean, minimalist space displaying works, developer skills, timeline history, and custom contact configurations.

Project ShowcaseInteractive CVFeedback Forms
Management

CRM Platform

Clean workspace structure to manage relationships, activities list, filters, and client history events.

Search filtersClient detail viewsInteractive charts
SaaS Application

Analytics Product

Engineering console for displaying performance metrics, billing records, database queries, and response charts.

tRPC-style layoutStripe billing integrationsLive tables
Enterprise

Cybersecurity Platform

High-security themed dashboard displaying incident telemetry, network scans, server status, and security score.

Vulnerability scansStatus signalsLog streams
Design Intelligence

Not just code. Production-ready web assets.

Generic AI code outputs often suffer from invalid styles, layout gaps, and poor accessibility structure. FastApp embeds strict design system blueprints and a self-healing compiler to validate output.

Semantic Blueprinting

Constructs clean HTML5 structures. Utilizes appropriate semantic landmarks (main, header, footer, section) instead of simple nested divs.

Design Tokens Enforcement

Locks typography, responsive columns, component scaling, and palette rules matching tailwind variables to prevent styling collisions.

Accessibility Guardrails

Validates contrast guidelines, aria labeling, accessibility standards, and markup hierarchies automatically on every compilation step.

Self-Healing AST Parser

AST validations check syntax sanity. Invalid structures or layout gaps are detected and auto-repaired in real time.

Validator Analytics Console

AST.validator.telemetry_layer

98%
Quality Score
0
HTML Errors
100%
WCAG Compliance

Validation Checklist

Tailwind Theme Token Consistency
PASS
Semantic landmarks hierarchy check
PASS
Contrast ratios & accessibility checks
PASS
AST structural repair verification
RESOLVED
Execution: 42msObserved by FastApp Validator Agent
Architecture Stack

Powered by a modern full-stack AI toolchain

FastApp is built with state-of-the-art frameworks to deliver blistering deployment speeds, type-safety, and deep generative capabilities.

Frontend & Routing

Next.js

App Router layouts, SSE compilation streaming, and server side security context rendering.

Language

TypeScript

Robust full-stack type safety ensuring consistent structures across planner, generator, and client.

Database Layer

Drizzle ORM

Type-safe database relations and migrations, avoiding complex SQL overheads.

Storage Engine

Neon PostgreSQL

Serverless relational data layer hosting client project details, user permissions, and deployment state.

Primary LLM Router

Gemini

Google Gemini 2.5 Flash acts as the primary layout blueprint planning and code compilation orchestrator.

Inference Engines

OpenAI & Anthropic

Secondary compilation pipelines query models like GPT-4o or Claude 3.5 Sonnet to handle complex logic requests.

Inference Router

OpenRouter

Acts as a unified fallback layer to guarantee uninterrupted generation service levels.

Engineering Overview

Architected for scale and stability

FastApp follows the Domain-Driven Design (DDD) model, separating compiler concerns from standard user management layers.

fastapp-core/src/lib/pipeline.ts
import { PlannerService, GeneratorService } from "./services";
import { ASTValidator } from "./validator";
// -------------------------------------------------------------
export async function compilePage(prompt: string) {
// Stage 1: Construct JSON Blueprint
const blueprint = await PlannerService.createBlueprint(prompt);
PlannerSchema.parse(blueprint);

// Stage 2: SSE Stream HTML Markup & CSS
const codeStream = await GeneratorService.streamCode(blueprint);

// Stage 3: Self-healing AST Repair Verification
const cleanCode = ASTValidator.healHTML(codeStream);

// Stage 4: Instant Preview Registration
return await PreviewService.registerPreview(cleanCode);
}
TypeScript 5.4Clean Architecture Codebase

Planner-First Abstraction

Zod Schema

Before writing any code, the user's prompt is routed to the planning layer. FastApp creates structured layouts, schema boundaries, and dependencies inside a Zod schema blueprint.

SSE Streaming Generator Layer

SSE Stream

FastApp feeds the planning blueprint to the code generation engine. Client applications receive live HTML markup streamed token-by-token via Server-Sent Events (SSE).

Validator AST Post-Processor

AST Parser

An AST-based repair engine reviews the raw output. If missing tailwind brackets, unclosed tags, or broken structures are found, the validator corrects them automatically.

Repository Storage Pattern

Clean Architecture

Decouples the database engine (Drizzle/PostgreSQL) from model endpoints. Everything is wrapped under consistent interfaces to allow seamless unit tests and fallbacks.

Turn ideas into production-ready pages

Start building gorgeous layout assets today. The free tier contains credits for planning, generation validation, and instant edge preview URLs.

No credit card requiredFree tier availableOpen source on GitHubMulti-model AI