Shopify API integration service – connect inventory, ERP, logistics and LINE

What a Shopify API integration can do

A Shopify API integration uses Shopify's public APIs to exchange product, inventory, order and customer data with other systems automatically. Three tools do most of the work:

• Admin API: create products, update stock, read orders and customers – everything the admin panel does, from code. GraphQL is now the main version
• Webhooks: Shopify notifies your other systems the moment an order is placed or stock changes
• Storefront API: product display and cart features for screens outside the Shopify theme – the basis of a headless setup

Combined, they link your store with inventory software, an ERP, a warehouse system, accounting, LINE or in-store POS in one flow. Start by writing down the single manual task that costs you the most time – that is your first integration candidate.

Existing app or custom app development?

The Shopify App Store has many public apps for inventory sync, shipping and LINE. The first check is whether the system you want to connect already has one.

• A public app is enough when the other side offers an official Shopify connection – common for major inventory, order management and carrier services
• A custom app fits when you run an in-house ERP, have customer-specific prices or billing cycles, or use a product code scheme no app supports
• A mix works when apps cover most of the flow and a small integration script fills the gap

Custom Shopify development is usually built as a private custom app for your store only. Compare monthly app fees against development and maintenance over a few years, together with the hours saved, and the choice becomes much clearer. If your needs are mostly about theme and design, see Shopify customization.

What to settle for each type of connection

Each integration partner brings its own questions. These are the points worth deciding at the design stage:

• Inventory and ERP: which system holds the master stock figure, how often it syncs (instantly or every few minutes), and a mapping of SKUs between systems
• Logistics and warehouse: when shipping orders go out, how tracking numbers return to Shopify to trigger the shipping email, and how cancellations or address changes are handled
• LINE: how a LINE user is matched to a Shopify customer, which events send a message (shipping, abandoned cart), and how consent is collected
• B2B sales: whether customer-specific prices, invoice payment and bulk orders come from Shopify's built-in features, an app or the API

We go deeper in LINE and e-commerce integration and B2B e-commerce. For any connection, a one-page diagram of who owns each piece of data and which way it flows keeps the spec stable later on.

When Shopify headless is worth it

In a headless setup, Shopify keeps handling products, inventory and checkout, while the storefront customers see is built with a separate framework – Shopify's own Hydrogen, or Next.js and similar tools on top of the Storefront API. It makes sense when you:

• Want a brand site, editorial content and the shop in one experience that goes beyond what a theme allows
• Need the same products and stock on several screens, such as a mobile app or in-store displays
• Run multiple languages and regions and want fine control over speed and structure

Headless also raises the initial build cost, many theme apps stop working out of the box, and every update needs a developer. For a small catalog that you edit in-house, a customized theme plus API integrations is almost always enough. Consider headless once you can name concrete things your current theme cannot do.

How the project runs – and common pitfalls

A Shopify API integration usually goes: map the workflow, build a data mapping, test on a development store, switch over, then monitor. Most problems come from the preparation around the code.

• No decision on which system owns stock or prices, so both overwrite each other and the data drifts
• Bulk updates ignore API rate limits and stall during a sale
• Shopify releases a new API version every quarter and retires old ones, and nobody is assigned to keep the integration current
• Failed syncs send no alert, and missed orders go unnoticed for days
• Testing happens on the live store and touches real orders and stock

It helps to have ready: a short description of who does what in your current workflow, the other system's spec or a sample CSV, your product code list and its API terms. Run realistic test orders on a development store before going live.

How UNANOBO handles Shopify integration: a free demo first

Before you commit, UNANOBO builds a free demo of your Shopify store with your own brand and products. After hearing how your operations run, we also show an integration plan: which parts run on apps and which need a custom app. You decide whether to go ahead once both the store and the plan make sense to you.

The process is simple: free demo, feedback, launch, growth. The founder handles design, development and maintenance personally, so the person who knows your integration spec stays your contact throughout. Everything runs by message, in Japanese or English, and the store and app accounts stay in your name.