Build apps for the world's most modern jewelry platform.
The K99 App Marketplace lets you ship integrations, animations, storefront blocks, AI tools, and back-office automations to thousands of independent jewelers — inside a sandboxed runtime designed so merchants never have to wonder whether your code is safe.
Security-first sandbox
Every app runs in an isolated iframe with explicit, capability-scoped permissions. Apps can't read merchant secrets, exfiltrate customer data, or touch the parent DOM unless the merchant grants the matching scope.
Real extension surface
Storefront blocks, admin panels, checkout extensions, webhook subscribers, scheduled jobs, and AI tool plugins — all with typed contracts. Build once, ship to every K99 merchant.
Built-in distribution
Listing, billing, trials, and merchant install flow handled by the marketplace. You focus on the product; we handle invoicing, taxes, and payouts.
What you can build
The K99 SDK exposes typed extension points across the platform. Anything inside these surfaces is fair game.
Theme blocks
Drop-in product, collection, and page sections — sandboxed iframes with a typed data API.
Checkout extensions
Add upsells, custom fields, and payment widgets without touching merchant code.
Admin app pages
Full back-office UIs surfaced inside the K99 admin shell, with native nav and theming.
Webhooks & jobs
Subscribe to platform events (orders, customers, inventory) or schedule background work.
AI tool plugins
Register tools that K99AI (Yen) can call on behalf of the merchant — with scoped permissions.
Custom data models
Define your own metaobjects and extend native records with namespaced metafields.
No app on K99 can quietly hurt a merchant's store.
Shopify-style app stores have repeatedly been used as malware vectors — fake reviews, swapped-out scripts, supply-chain injection. We've designed the K99 marketplace from day one to close those holes:
- Sandboxed runtime. App code never executes in the merchant's page context. All UI runs in a cross-origin iframe with a hardened CSP.
- Capability scopes. Apps declare exactly what data and actions they need. Merchants see and approve every scope at install time.
- Signed, immutable bundles. Approved app versions are content-addressed and served from our CDN. Developers can't hot-swap code post-review.
- Mandatory review for every release. Static analysis, dependency scanning, and a human reviewer for any release that requests sensitive scopes (PII, payments, customer email).
- One-click kill switch. K99 can disable any app for any tenant — or globally — in seconds. We log every cross-boundary call for audit.
From idea to install
- 01
Apply
Tell us about your app idea. Approved partners get sandbox credentials and SDK access.
- 02
Build
Develop locally against our test tenant using the K99 CLI and TypeScript SDK.
- 03
Submit
Push your signed bundle. Automated checks + reviewer feedback within 5 business days.
- 04
Earn
Merchants install in one click. We handle billing; you keep 80% of revenue.
The marketplace launches in 2026.
Early-access partners get featured placement, dedicated migration help, and a higher revenue share for their first 12 months.