Notifi is an embedded Shopify app I built and operated solo for five years. It captures
shopper demand on out-of-stock products and turns it into recovered revenue — with
real-time restock emails, full-funnel analytics, and order-level conversion attribution.
M+
Millions
Webhooks Processed
100K+
Restock Emails Sent
5 Years
Live in Production
4.3★
App Store Rating
The Challenge
When a shopper lands on a sold-out product, the sale is usually lost twice over: the customer
leaves, and the merchant never learns there was demand. Out-of-stock pages are one of the
largest silent leaks in e-commerce, and most stores had no way to capture that intent —
let alone prove that recovering it made them money.
Silent Lost Demand
Shoppers hit an out-of-stock variant and left, with no signal captured and no way to win them back.
No Restock Signal
Merchants had no data on which variants shoppers were actually waiting on to inform what to reorder.
Slow, Manual Outreach
Re-engaging interested shoppers meant manual exports and one-off emails — if it happened at all.
Disconnected From Inventory
Generic email tools weren't wired into Shopify's real-time inventory, so alerts couldn't fire the moment stock returned.
Unprovable ROI
Even when alerts went out, merchants couldn't tie a resulting order back to the email that drove it.
The Solution
Notifi is a complete, embedded Shopify SaaS built on Django and Celery. It installs through
Shopify OAuth, injects a signup form onto out-of-stock products, and listens for inventory
webhooks — emailing every waiting shopper the moment their variant is back, then
attributing the resulting orders back to the exact email.
Event-Driven Restock Alerts
HMAC-verified inventory_levels/update webhooks are persisted and handed to Celery, so the HTTP handler returns instantly while emails dispatch asynchronously through Sendinblue.
Shopify Webhook
Inventory update fires when a variant is restocked.
Verify & Persist
HMAC-validated and stored before any work begins.
Celery Queue
Async workers fan out emails to everyone waiting.
Email + Attribution
Tracked links tie the order back to the email.
A restock event flows from Shopify through verified, queued processing into an attributed sale.
Seamless Storefront Capture
A JavaScript ScriptTag injects an email signup form directly onto out-of-stock product pages — no theme edits required from the merchant.
Full-Funnel Analytics
An embedded dashboard tracks the entire journey — page views, leads, sends, clicks, and conversions — plus the variants shoppers are most waiting on.
Order-Level Conversion Attribution
Tracking parameters stamp each lead onto the product link, then Shopify's customer-journey data ties an order back to the exact email — with an email-and-variant fallback — so merchants see real recovered revenue.
Multi-Language & Tiered Billing
Localized email templates served a global merchant base, billed through Shopify's recurring-charges API across Basic, Starter, Pro, and Enterprise plans.
Results
Notifi ran as a real, revenue-generating product for five years, serving thousands of
merchants at over $1,000 in monthly recurring revenue. It processed millions of inventory
webhooks and sent hundreds of thousands of restock emails, earning a 4.3-star App Store
rating — a complete commercial funnel I designed, shipped, and operated end to end as
a solo founder.
Proven at Scale
Millions of webhooks processed and 100K+ emails sent through an async, event-driven pipeline.
Sustained Revenue
$1,000+ MRR across four pricing tiers, billed natively through Shopify.
Thousands of Merchants
A global install base validated the product, reflected in a 4.3-star rating.
Five Years in Production
Stable, low-touch operation over a half-decade lifespan, built and maintained solo.
Demonstrable ROI
Order-level attribution let merchants see exactly how much revenue Notifi recovered for them.
Shipped Pragmatically
Deep Shopify domain knowledge and a bias toward shipping turned a complete idea into a money-making product, fast.
"Customers love getting notified the second their size is back — and I can finally see the sales it brings in."
