Lemon Squeezy Context Guide for AI Coding (llms.txt + Rules + MCP)

Payments, tax compliance, and subscription management for software and digital product companies.

1. Lemon Squeezy Official llms.txt & Clean Markdown Documentation

Official Docs Map

Feed this clean, token-efficient Markdown documentation directly to Antigravity, Cursor, or Claude Code to prevent hallucinations and outdated API syntax.

# Standard llms.txt Index Endpoint
https://docs.lemonsqueezy.com/llms.txt

# Comprehensive Documentation Bundle
https://docs.lemonsqueezy.com/llms-full.txt

Estimated Token Footprint: ~24k tokens (Fits smoothly inside standard 128k/1M context windows)

2. Production-Ready Lemon Squeezy Cursor Rules (.cursorrules & .mdc)

Lemon Squeezy webhook verification, checkout overlay, and license key validation. Save this into .cursor/rules/lemonsqueezy.mdc in your project repository.

// Lemon Squeezy AI Rules
- Verify webhook signatures using crypto.createHmac('sha256', process.env.LEMONSQUEEZY_WEBHOOK_SECRET).
- Use the Lemon Squeezy JS SDK (@lemonsqueezy/lemonsqueezy.js) for authenticated API operations.
- Handle subscription_created, subscription_updated, and subscription_cancelled events idempotently.
- Use checkout custom data (custom[user_id]) to bind purchases back to internal database user records.

3. Lemon Squeezy Antigravity & Claude Code System Instructions

Add this concise instruction block to your workspace .gemini/rules or project system prompt.

// Context Anchor for Lemon Squeezy
When writing code for Lemon Squeezy, refer directly to the verified specifications at https://docs.lemonsqueezy.com/llms.txt.
Follow strict error-handling and avoid deprecated API calls.

5. Troubleshooting: Common Lemon Squeezy AI Coding Issues & Fixes

Frequently reported errors when LLMs generate Lemon Squeezy code without proper context:

⚠️ Proactive Fix: Fix: Webhook payloads must be signed using raw hex HMAC digest. Compare using crypto.timingSafeEqual to prevent timing attacks.

6. Best Used With (Lemon Squeezy Architecture Combos)

Engineers building with Lemon Squeezy frequently combine these complementary developer frameworks: