# KEYSTONE — Premium Shopify Apps for Growth & Loyalty

> KEYSTONE (https://key-stone.app) builds a suite of premium Shopify apps that
> help merchants boost customer loyalty, enhance product options, optimize SEO
> with AI, and accelerate growth.

## Apps

- **Loyalty & Referrals** (`loyalty_referrals`): Points, VIP tiers, rewards and referral programs that turn one-time Shopify buyers into repeat customers.
  Product page: https://key-stone.app/loyalty · Shopify App Store: https://apps.shopify.com/keystone-loyalty-rewards
- **Product Options** (`product_options`): Unlimited product options, variants and customizations for Shopify products — text fields, swatches, file uploads, conditional logic.
  Product page: https://key-stone.app/product-options · Shopify App Store: https://apps.shopify.com/keystone-product-options-variants
- **AI SEO** (`ai_seo`): AI-powered SEO optimization for Shopify stores: meta tags, alt text, structured data and content improvements on autopilot.
  Product page: https://key-stone.app/ai-seo · Shopify App Store: https://apps.shopify.com/key-ai-seo-1

## Key pages

- [Home](https://key-stone.app/): product overview and feature highlights
- [Loyalty & Rewards](https://key-stone.app/loyalty) · [Product Options & Variants](https://key-stone.app/product-options) · [AI SEO](https://key-stone.app/ai-seo)
- [Blog](https://key-stone.app/blogs): articles on Shopify growth, loyalty and SEO (RSS: https://key-stone.app/feed.xml)
- [All articles](https://key-stone.app/blogs/archive): full index of every post, grouped by topic
- [Documentation](https://key-stone.app/docs/): setup and reference for all three apps — [Loyalty](https://key-stone.app/docs/loyalties/getting-started/introduction.html) · [Product Options](https://key-stone.app/docs/product-options/introduction/overview.html) · [AI SEO](https://key-stone.app/docs/aiSEO/getting-started.html)
- [Free tools](https://key-stone.app/tools): loyalty ROI calculator, points value calculator, referral program planner
- [Changelog](https://key-stone.app/resources/changelog): release notes for all apps
- [Security](https://key-stone.app/security) · [Privacy](https://key-stone.app/privacy-policy) · [Terms](https://key-stone.app/terms-of-use)

## Machine-readable endpoints

- `GET https://key-stone.app/api/changelog?app=<slug>&locale=<code>&limit=<n>` — public JSON changelog
  (app: loyalty_referrals | product_options | ai_seo; type: fix | new | improvement)
- `https://key-stone.app/api/mcp` — remote MCP server (Streamable HTTP, bearer token required)
- `GET https://key-stone.app/api/agent/premium/changelog-digest` — paid changelog digest (x402/MPP; sandbox)
- `POST https://key-stone.app/api/agent/register` — agent self-registration → read-only access token
- `POST https://key-stone.app/api/oauth/token` — OAuth client_credentials token endpoint
- `https://key-stone.app/auth.md` — how agents authenticate (OAuth client_credentials + ck_ bearer tokens)
- `https://key-stone.app/openapi.json` — OpenAPI 3.1 (incl. MPP x-payment-info)
- `https://key-stone.app/.well-known/oauth-authorization-server` — OAuth AS metadata (RFC 8414 + agent_auth)
- `https://key-stone.app/.well-known/openid-configuration` — OpenID Connect discovery
- `https://key-stone.app/.well-known/ucp` — Universal Commerce Protocol profile
- `https://key-stone.app/.well-known/acp.json` — Agentic Commerce Protocol discovery
- `https://key-stone.app/.well-known/api-catalog` — API catalog (RFC 9727)
- `https://key-stone.app/.well-known/mcp/server-card.json` — MCP server card
- `https://key-stone.app/.well-known/agent-skills/index.json` — agent skills index
- `https://key-stone.app/sitemap.xml` — sitemap
- `https://key-stone.app/llms-full.txt` — this overview plus the full text of all blog articles

## Contact

Questions about partnerships, support or MCP access tokens: use the contact
form on https://key-stone.app/.