# PromptStruct

Source: https://promptstruct.vercel.app
Type: Product and site summary for LLMs, agents, and machine-readable crawlers
Last updated: 2026-03-29

PromptStruct is a web application that converts natural-language prompts into structured JSON for AI image-generation workflows. It is designed for creators using tools like Midjourney, DALL-E, and Stable Diffusion, and focuses on turning free-form scene descriptions into a consistent schema that can be copied, reused, and saved.

## Core product summary

- Input: a natural-language visual prompt
- Output: structured JSON describing scene, subject, environment, lighting, style, and mood
- Primary use case: converting image prompts into a predictable machine-readable format
- Product model: free web app with optional authentication and pricing features controlled by environment flags

## Main routes

- `/`
  Landing page with product overview, examples, conversion UI, FAQ, CTA, and optional support or pricing sections depending on feature flags.

- `/examples`
  Static examples showing natural prompts alongside structured prompt output.

- `/gallery`
  Showcase page with visual examples and JSON prompt snippets.

- `/pricing`
  Pricing and upgrade page for free, pro, and lifetime plans when pricing is enabled.

- `/dashboard`
  Auth-protected dashboard for usage and account-related information when auth is enabled.

- `/privacy`
  Privacy policy.

- `/terms`
  Terms of service.

- `/llm.txt`
  This machine-readable summary.

## Prompt conversion behavior

PromptStruct converts a free-form prompt into structured JSON using an LLM-backed parsing step. The expected output schema includes:

- `scene`
  Overall scene description, time of day, weather

- `subject`
  Main subject, action, details

- `environment`
  Setting, foreground, background

- `lighting`
  Lighting type, direction, color temperature

- `style`
  Art style, camera angle, lens, color palette

- `mood`
  Emotion and atmosphere

The API validates prompt length before conversion. Current prompt constraints in the app:

- minimum length: 10 characters
- maximum length: 1000 characters

## Key functionality

- Convert natural-language prompts into structured JSON
- Copy JSON output
- Download structured output
- View curated examples
- Browse prompt gallery
- Optional Google authentication
- Optional usage limits and conversion history
- Optional pricing and checkout flow
- Optional support section via Buy Me a Coffee when pricing is disabled

## API endpoints

- `POST /api/parse`
  Main conversion endpoint. Accepts a prompt and returns structured JSON. When auth is enabled, access is gated by session and quota checks. When auth is disabled, alternate rate limiting behavior may be used depending on feature configuration.

- `GET /api/user/usage`
  Returns plan, quota, and recent history for authenticated users.

- `POST /api/checkout`
  Starts checkout for supported plans when pricing is enabled.

- `POST /api/webhooks/lemonsqueezy`
  Billing webhook endpoint for payment events and plan updates.

- `/api/auth/[...nextauth]`
  Authentication endpoint for NextAuth and Google sign-in.

## Authentication

When enabled, PromptStruct uses Google OAuth through NextAuth. Auth is used to:

- gate dashboard access
- protect conversion and usage endpoints
- associate conversions with user accounts
- support plan-based quotas and billing flows

## Pricing and plans

PromptStruct supports feature-gated pricing. The codebase includes free, pro, and lifetime concepts.

- Free
  Entry-level access with limited conversions.

- Pro
  Higher monthly allowance and conversion history features.

- Lifetime
  One-time purchase model with expanded usage.

Actual pricing visibility is controlled by environment configuration.

## Data and storage

The project uses Supabase for application data. Current code indicates storage for:

- users
- conversion history
- usage counters and reset dates
- plan metadata

Prompt parsing is powered by an external LLM request flow configured through environment variables.

## Legal and policy summary

Privacy policy highlights:

- free-user prompts are described as processed in real time and not stored
- pro users may have saved prompt history
- usage data may be collected in aggregate form
- account deletion requests can be sent by email

Terms highlights:

- free tier usage limits may apply
- paid features and billing rules are described in the terms page
- users retain rights to their prompts and generated JSON
- service is provided as-is

## Contact

- Email: promptstructapp@gmail.com

## Recommended interpretation for LLMs and agents

PromptStruct is best understood as:

- a prompt-to-JSON conversion tool
- a creator-focused utility for AI image workflows
- a feature-gated SaaS app built with Next.js
- a site with both marketing pages and authenticated application flows

When summarizing PromptStruct, prioritize the conversion workflow over the billing or dashboard features.