Fluctum
Real-Time Dynamic Pricing for Medusa
Open source plugin, starter backend, and starter storefront.See more
What is Fluctum?
Fluctum is an open-source dynamic pricing plugin for Medusa stores. It is built for precious metals and any catalog where market prices move constantly. Fluctum ships as three connected components: Medusa plugin, backend starter, and storefront starter. Teams can launch quickly, then customize deeply in TypeScript.
You keep the full Medusa platform benefits: multi-region, multi-currency, promotions, customer management, localized taxes, shipping, and payments. Fluctum adds real-time SSE price updates and checkout price locks validated before order completion.
Medusa-native
Built as a Medusa plugin; drops into any Medusa project seamlessly.
Open source
MIT license, community-first; fork and extend freely to fit your business.
Production-ready
SSE streams, price locking, and checkout validation - all built in and battle-tested.
Make It Your Own
Medusa separates backend from frontend - your storefront can look exactly the way you want.
- Use any framework: Next.js, SvelteKit, Remix, or plain HTML.
- The plugin provides the data and logic; your design team provides the UI.
- Our demo uses Next.js 16 + Tailwind, but you can build a Vue app, React Native mobile app, or even an in-store kiosk interface.
Formula Engine
const final_price =weight ×spot_price ×factor ×fx_rate;
Integrations
Since Fluctum is built on Medusa, you inherit the entire Medusa ecosystem out of the box.
GoldAPI.io / nFusion
Live precious metals spot prices
Stripe / PayPal
Native Medusa payment providers
ShipStation / InPost
Automated fulfillment and shipping
Avalara / TaxJar
Automated tax calculation
Mailchimp / SendGrid
Transactional emails and marketing
Odoo / Base
ERP sync via custom API
Built for real-time commerce
Connect a provider
Plug in GoldAPI.io, your ERP, or a custom feed. Fluctum constantly ingests the latest spot prices.
Prices flow via SSE
Every storefront client receives live spot prices over a single persistent Server-Sent Events connection.
Checkout locks the price
When the buyer proceeds, Fluctum creates locks from the latest spot prices stored in your database for your configured window (for example, 2 or 10 minutes), then validates them at order completion.
Where Fluctum fits
Precious Metals
Gold and silver bullion dealers needing sub-second spot accuracy.
Industrial Metals
Copper, platinum, and palladium wholesale operations.
B2B & ERP-driven
Live catalog pricing synced directly with internal inventory systems.
FX-Sensitive Goods
High-value items that require constant currency conversion adjustments.
Deploy your way
Medusa Cloud
One-click deployment on Medusa's official managed infrastructure. Optimized for scale.
Self-Hosted
Full control on your own AWS, GCP, or bare metal infrastructure.
Want a fast implementation path? Start from ourbackend + storefront starter.
Frequently asked questions
What is Fluctum?
Fluctum is an open-source dynamic pricing plugin for Medusa that streams live spot prices to your storefront over Server-Sent Events and locks the price a customer sees the moment they enter checkout, so it stays valid through order completion.
Is Fluctum free and open source?
Yes. Fluctum is MIT-licensed and published as @u11d/medusa-dynamic-pricing on npm. You can install it, read the source, and self-host it without any license fees.
How does Fluctum keep prices in sync with the market?
A scheduled job fetches ask, bid, and spot prices from a configurable provider (GoldAPI.io, your ERP, or a custom feed) at whatever interval you set, then broadcasts every update to connected storefronts over a single SSE connection.
What happens to the price when a customer checks out?
When a shopper enters checkout, Fluctum locks the price using the latest spot price stored in your database for a configurable window (for example 10 minutes), then validates the lock still exists and hasn't expired before the order completes.
Does Fluctum ever override Medusa's own prices?
No. Fluctum never writes to Medusa's price tables. Final prices are computed on the frontend from the live spot price and each variant's pricing rule, keeping Medusa's core pricing engine untouched.
What industries is Fluctum built for?
Fluctum was built for precious metals dealers (gold, silver) but fits any catalog where prices move constantly - industrial metals, FX-sensitive goods, and B2B catalogs driven by an ERP feed.
How do I deploy Fluctum?
Deploy on Medusa Cloud for one-click managed hosting, or self-host on your own AWS, GCP, or bare-metal infrastructure using the open-source backend and storefront starters.
Every few seconds our spot prices change - won't re-fetching prices for each shopper overload our servers?
No. A single scheduled job fetches spot prices once per interval and broadcasts every update to all connected storefronts over one Server-Sent Events connection, so server load stays flat no matter how many shoppers are browsing.
Could a customer exploit a slow checkout to lock in a price from before the market moved against us?
No. Price locks are created from the latest spot price the moment checkout starts and are re-validated at order completion, so neither the buyer nor the seller can benefit from a stale price slipping through.
We already run Medusa with promotions, multi-currency, and custom tax rules - do we have to rebuild any of that for live pricing?
No. Fluctum is a Medusa plugin, not a replacement backend. It layers real-time pricing and price locks on top of your existing store, so promotions, multi-region, multi-currency, and tax setup keep working exactly as before.
Our storefront isn't built in Next.js - will dynamic pricing lock us into a specific frontend framework?
No. The plugin exposes plain HTTP and SSE endpoints, so any frontend - Next.js, SvelteKit, Vue, React Native, or a custom kiosk UI - can consume live prices the same way our reference storefront does.
Spot prices are quoted in USD but we sell in multiple currencies - how do we avoid manual FX conversion errors?
An optional currency conversion module refreshes FX rates on a schedule and applies them automatically the moment prices are locked, so checkout totals convert consistently without manual spreadsheets.
Ready to ship live pricing?
Get in touch to discuss end-to-end implementation support or reach out at hello@u11d.com.