# A Shopify app designed and shipped end to end

> I built a complete Shopify app, from installation on a store through to its visual integration into the theme.

- Source canonique : [https://allaux.fr/en/realisations/application-shopify-complete](https://allaux.fr/en/realisations/application-shopify-complete)
- Langue : EN
- Dernière mise à jour : 2026-09-30

## The context

A Shopify app isn't just a piece of code running somewhere: it needs to install cleanly on a store, authenticate securely, react to store events in real time, and be able to integrate visually into the theme without the merchant touching any code. That's the full scope I built: an app that can be installed on any eligible Shopify store, not a prototype limited to a single use case.

The goal was to cover the entire technical chain Shopify expects from a distributable app, meeting its security and performance requirements.

## What I did

1. **OAuth authentication** — Set up Shopify's own installation and authorisation OAuth flow, with access-token management for each installed store.
2. **Receiving signed webhooks** — Listened for events sent by Shopify (order created, product updated, app uninstalled), with systematic signature verification to reject any forged request.
3. **Theme extension** — Built a block that plugs directly into the Shopify theme editor, letting the merchant position the feature without writing any code.
4. **Managing the app lifecycle** — Handled uninstallation, Shopify plan changes and recurring billing, so the app stays consistent throughout its whole usage lifetime.

## Outcome

> The app is functional from installation through to uninstallation, with a visual theme integration designed to be configured by a merchant with no technical skills.

## FAQ

### Why does webhook signature verification matter?

Without it, nothing guarantees that a received request actually comes from Shopify rather than a third party trying to trigger an unauthorised action on the app.

### Does the theme extension require technical skill from the merchant?

No, that's precisely the point: once the app is installed, the block is added to the theme from Shopify's visual editor, without writing any code.

### What happens if Shopify changes its APIs?

Shopify regularly releases new API versions with a transition period; the app needs to be tracked and adapted to that pace to stay compatible.

### Can this app be installed on several stores at once?

Yes, the OAuth architecture I built handles multiple installed stores simultaneously by design, each with its own access and its own data.