Types of Ecommerce APIs and How To Integrate Them (2025)

Over the past two decades, APIs have had a powerful impact on ecommerce businesses. Today, merchants are building world-class experiences with best-of-breed technologies and commerce capabilities via API layers. 

This has given development teams a new level of flexibility to build ecommerce websites that meet their brand’s needs today—and can adapt to future demands.

In this article, we’ll explain the ins and outs of an API, including the types of ecommerce APIs on the market today, the benefits of using an ecommerce API, and the most compelling use cases you should consider. 

What is an ecommerce API?

API is an acronym for application programming interface, which Red Hat explains is a set of definitions and protocols for building and integrating application software. Ecommerce APIs are a subset of APIs that facilitate communication and integrations among different ecommerce applications or services without having direct access to the source code. 

For ecommerce platforms in particular, APIs have become a critical part of creating a platform that’s extensible and interoperable. Today, APIs are seen as a must-have, with developers expecting API availability that enables them to use existing functionality without having to rebuild from scratch. 

How do ecommerce APIs work?

Ecommerce APIs, like most APIs, are shared via documentation, accessed via API calls, and secured via access tokens. Shopify, for example, hosts its API documentation publicly—as do companies like Instagram and Spotify.

API documentation is fairly standardized and typically describes how developers should make a connection, send requests, and how data should be transferred. APIs come in a wide variety of formats, but the most common ones for ecommerce are REST (representational state transfer) and GraphQL.

Even though most APIs are shared through documentation, not all API documentation is public. Many companies keep API documentation internal to ensure that only approved developers can access it. 

Other companies focus on exposing APIs so that first and third-party developers can access and build with them freely. Other companies still might keep most of their APIs private, but gate outside access through beta testing programs and exclusive partnerships. 

As a result, APIs are essential to platforms – and to ecommerce platforms in particular—in a way that they aren’t to other kinds of businesses. Similar to when Amazon split itself into a web of small teams connected by separate interfaces, the best platforms built a core service and enabled developers to build new services on top of original functionality—all via API. 

API vs. traditional integrations

File-based integrations like electronic data interchange (EDI) and scheduled file transfers (SFTP) have been used in supply chain management for decades. They are stable, standardized, and are the required language for many big-box and B2B trading partners. 

As buyers' expectations for speed and accuracy changed, modern APIs emerged to keep up with the accelerating pace of commerce. The approaches differ on one key dimension: real-time events versus scheduled batches.

• Modern API integrations, like Shopify’s GraphQL Admin API, are built for immediacy. They use webhooks to react to events, like a new order or an inventory update, the second they happen. Data is exchanged programmatically over secure HTTPS connections, using flexible, platform-specific schemas that can be updated efficiently.
• Traditional integrations operate on a schedule. They exchange data in batches via EDI, using standards like X12 in the US or EDIFACT globally, or through CSV files dropped on an SFTP server. These systems are incredibly robust and standardized across entire industries. Billions of GS1 EANCOM messages are still exchanged annually across retail, healthcare, and logistics. However, their batch-window nature means data freshness is delayed by hours or days.

Modern APIs are designed for high-volume, efficient data transfer. Shopify’s GraphQL Admin API, for example, uses a cost-based rate-limiting model (e.g., 50 points per second with a 1,000-point bucket). Developers can fetch all the data they need in a single call. 

EDI’s strength is its stability. Its standards are slow to change by design. This makes it ideal when coordinating vast supply chains, especially when partners mandate its use for documents like purchase orders (X12 850), advance-ship notices (856), and invoices (810).

The best approach is a hybrid one: 

• Use APIs and Webhooks for internal systems where speed is a competitive advantage. This is the clear path forward for connecting your Shopify store, order management system (OMS), product information management (PIM), and custom apps.
• Keep EDI at the edge of your enterprise, where it remains the required standard for communicating with B2B partners and big-box retailers.

Types of ecommerce APIs

Core commerce APIs

These APIs help developers assemble and form the essential parts of an ecommerce business, such as product catalogs, B2B, and discounts. For example:

• Admin API (GraphQL): This API manages products, orders, inventory, and customers. Shopify now requires that all new public apps use the GraphQL Admin API, as the REST Admin API has been deprecated.
• Storefront API (GraphQL): This API provides the tools to build headless commerce experiences, powering custom websites, mobile apps, and in-store displays. It has no request-count rate limit.
• Webhooks: These enable your systems to react in near-real time to events like new orders or product updates. Shopify requires mandatory webhook topics for apps distributed on the App Store to ensure compliance.

Payment and transaction APIs

Use these to build new payment gateways or alternative payment methods. Your app completes payment sessions using GraphQL mutations after receiving an initial call from Shopify.

Customer data and customer relationship management (CRM) APIs

These APIs, including ones that offer data analysis and customer privacy features, make it easier for companies using the Shopify platform to leverage customer data effectively while following privacy and compliance regulations. 

Inventory management APIs

Inventory management APIs let you query and update stock levels at each location using objects like InventoryLevel. You can make direct quantity adjustments and view stock on a per-location basis. 

These are also used to manage the fulfillment process, allowing you to route orders to specific warehouses or third party logistics providers (3PLs) and execute tasks like accepting, holding, or completing an order.

Marketing and analytics APIs

These Web Pixel APIs provide a sandboxed, standardized way to handle client-side tracking. They let you subscribe to standard customer events and fire tracking pixels with built-in awareness of the customer's consent choices. You can also use them to pull the data needed for your dashboards and reports. 

Shipping and logistics APIs

These APIs let you control every aspect of shipping. For example, register your carrier service to display real-time shipping rates from providers like FedEx, UPS, or custom services directly at checkout. Or, using Shopify Functions, you can write custom logic to hide, reorder, or rename delivery options at checkout

While each category contains numerous APIs, these examples illustrate the breadth of available features and functionalities. 

Essential ecommerce API use cases

Headless commerce implementations

Developers and merchants leverage Shopify’s full suite of headless development tools to build best-in-class custom experiences in less time and at lower costs. The foundation of Shopify’s headless solution is Storefront API, which gives you access to commerce capabilities critical for creating highly customized and relevant buyer experiences.

Storefront API is device and product-agnostic, which enables developers to build a wide range of unique buyer experiences across web, mobile apps, video games, AR/VR, and voice, and public apps/sales channels. It’s also deployed to the edge and serves all legitimate requests from both private and public clients without rate limits, allowing you to deliver best-in-class experiences to customers wherever they are.

Multichannel selling

To reach customers wherever they are, you can use the Admin API to manage product availability across all your sales channels, whether it's a marketplace, a point-of-sale (POS) system, or your online store.

For partners looking to build new channels, Shopify provides a clear set of requirements for sales channel apps. With Shopify, you can manage all your channels from a single, unified place within the Admin.

Custom checkout experiences

Merchants use Shopify checkout to accept orders and receive payments wherever they sell online. Shopify manages an average of 40,000 checkouts per minute per store and has processed over 5.5 billion orders. Trusted by the largest brands and flash sellers in the world, Shopify’s checkout platform is battle-hardened by our scale and ready for enterprises. 

Developers can build apps using a set of APIs to extend and augment Shopify checkout with new capabilities. 

• Checkout UI extensions: Add custom UI or content to the checkout process and order status page.
• Branding API: Customize the look and feel of checkout.
• Shopify Functions API: Extend or replace key parts of Shopify’s backend with custom logic.
• Web pixel app extensions: Track customer behavior.

Third-party integrations

The main way to sync data between Shopify and other systems is through webhooks, which provide real-time updates for events such as new orders or inventory changes, or via vetted apps from the Shopify App Store.

For merchant-led automation, you can build connectors for Shopify Flow, allowing users to create their own workflows that connect your app with tools like Slack, Google Sheets, or their enterprise resource planning (ERP) system.

B2B commerce automation

Shopify offers several APIs to enable merchants across all industries to manage orders, inventory, and customer data. B2B merchants juggling multiple contacts, locations, and prenegotiated payment terms can use Shopify’s suite of GraphQL APIs designed to help manage these constantly moving targets.

Shopify’s Admin API allows developers to add their own features, customize the Shopify user experience, and support enterprises managing back-office operations at large scale. These APIs are the primary way that your enterprise apps and back-end systems interact, integrate, and manage data related to your Shopify stores. 

An ERP (system, which offers finance, manufacturing, supply chain, sales, and procurement processes, has long been critical to enterprise success. Shopify’s Admin APIs are architected to integrate seamlessly with the most popular ERPs, enabling enterprises to manage complex business operations on Shopify more efficiently.

Business benefits of ecommerce APIs

Using ecommerce APIs provides multiple business benefits, all stemming from extensibility. Extensibility is the capability to build or improve software capabilities at scale, without extensive effort. 

The greatest benefit is that you rarely have to compromise. API-first companies like Stripe and Twilio have succeeded by consistently offering best-in-class features. In many cases, it’s not only more efficient to call on APIs instead of building features from scratch—you get a superior result. 

Key benefits include:

Faster time to market

An API-first strategy significantly accelerates development and deployment cycles. In 2024, data shows that 63% of teams can ship a new API in under a week, up from 47% in 2023, with daily deployments increasing to 8%. 

The same report found that 74% of organizations identified as API-first in 2024, and these leaders were 83% more likely to restore a failed API within an hour. 

Improved scalability

By using APIs, you can focus developers on building and maintaining new features rather than pulling them off existing projects when demand surges. With ecommerce APIs, you can add new components without altering the underlying architecture or redesigning for scalability. 

Enhanced customer experiences

APIs help build personalized experiences that customers (and B2B buyers) now expect. Today, 89% of business leaders say personalization is critical to success. With APIs, possibilities are vast:

1. Create a frictionless checkout using Checkout UI extensions to add a gift message field.
2. Use the Delivery Customization API to show only relevant shipping options based on cart contents or address.
3. For B2B or VIP tiers, APIs enable login-gated catalogs with customer-specific pricing and terms.

Cost efficiency and return on investment (ROI)

APIs have a direct and measurable impact on revenue. In fact, 62% of organizations reported working with revenue-generating APIs in 2024, and for 21% of companies, APIs drive over 75% of their total revenue. While results vary, the financial impact can be significant. 

For example, a May 2025 Forrester TEI study commissioned by Microsoft found that its API-management platform delivered a modeled 315% ROI over three years for a composite organization.

Shopify Functions and ecommerce APIs

Shopify Functions is a newer platform that lets developers extend or replace key parts of Shopify’s back-end logic with custom functions, enabling unique commerce experiences. 

Functions provide a set of APIs for customizing Shopify’s back end to build everything from checkout-validation rules to product bundles that display right in the checkout:

• Delivery Customization API: Rename, reorder, and sort the delivery options available to buyers during checkout.
• Order Discount API: Create a new type of discount that's applied to all merchandise in the cart.
• Product Discount API: Create a new type of discount that's applied to a particular product or product variant in the cart.
• Payment Customization API: Rename, reorder, and sort the payment methods available to buyers during checkout.

One of the key benefits is that enterprises don’t need to worry about managing their own servers for these custom functions, since Shopify handles management and scaling.

Ecommerce API implementation considerations

API security and authentication

For security, always use OAuth and request only the necessary permissions. Platforms often hide sensitive customer data, so your app needs a plan for when it cannot access this information and must adhere to strict privacy rules. Before processing a webhook, always verify the HMAC signature in the header to ensure the request is legitimate and secure.

Rate-limiting and performance

To keep your app from breaking, you must respect the platform's API rate limits. Determine whether the limit is based on a calculated query cost or a simple request count, and adjust your calls accordingly. For big jobs, like importing thousands of products, use asynchronous bulk operation APIs. Finally, make your webhook handlers idempotent, meaning they can safely run multiple times, since a failed webhook is often re-sent.

Documentation and developer experience

Good developer tools help you build faster. Pay attention to your platform’s API-versioning schedule and plan for regular updates so your app doesn't break when old versions are retired. Follow the platform's lead on technology, like a switch from REST to GraphQL. Use all the tools provided, such as command-line interfaces (CLIs) and API explorers, to build and test more quickly.

Integration complexity management

To keep your integration simple, use modern design patterns. Use webhooks for real-time events instead of constantly polling for updates. Move heavy tasks to asynchronous jobs so they don’t slow down your app. Design your integration to align with the platform's core logic for features such as orders and fulfillment, and incorporate API upgrades into your regular roadmap.

Choosing the right ecommerce API solution

Unified APIs vs. individual integrations

A unified API is like a universal remote for your integrations. You build one connection that works with many different providers at once, such as a multi-carrier shipping API. The main benefit is speed—you get broad coverage fast and only have to maintain one connection. The downside is that you might miss out on advanced features from a specific provider, as the unified API may not support everything.

• Choose a unified API when you need to connect to many services quickly, such as when comparing shipping rates across multiple carriers.
• Choose individual integrations when you need the specific, advanced features of one provider and have the resources to build a custom connection.

Shopify's API ecosystem

Shopify is built with a modular approach, making it easy for merchants to set up their stores and developers to extend the platform with apps and custom solutions using APIs. 

Shopify offers plug-and-play features that merchants can use to customize their stores, improve the shopping experience, and amplify their marketing efforts. Much of this work is powered by APIs.

Shopify provides all the API endpoints you need to integrate both new and existing first-party and third-party systems so that you can extend the functionality of Shopify’s core commerce platform. For enterprises, four key APIs include Admin APIs, Functions APIs, Storefront Edge APIs, and B2B APIs.

Evaluation criteria for API platforms

When choosing a platform, look for these key features:

• Security and Auth: It should use modern security, like OAuth, and have clear rules for protecting customer data. Make sure it has critical compliances like PCI DSS Level 1 for payment processing.
• Rate limits and throughput: Understand the rate limits, whether they are based on a query cost or a simple request count. The platform should also offer bulk operations for heavy data jobs.
• Webhooks reliability: Check if the platform automatically retries failed webhooks. Your code should be idempotent, so it can handle these retries without creating duplicate data.
• Versioning and deprecation: A predictable versioning schedule is best, giving you time to update before old versions are retired.
• Developer experience: Good documentation, SDKs, a CLI, and API explorers like GraphiQL are essential. They help your team build faster and with fewer errors.
• Operational visibility: The platform should have a public status page to show uptime and provide clear communication during outages.

Making commerce better for everyone requires everyone’s input

Shopify’s mission is to make commerce better for everyone. Commerce is complex and full of edge cases, and because it never stops evolving, that complexity can never be captured and solved in a single solution.

Shopify provides an extensible platform for our products and services that face merchants and partners, enabling them to swiftly and easily customize Shopify features to their needs. The platform also offers developer-facing APIs that enable third-party developers to solve unique problems via code. By offering this level of extensibility, even the most complex organizations can use Shopify to build fast, reliable apps, supported by the programming languages and frameworks their engineering teams already know and use. 

The goal is to develop solutions for the core problems that many commerce companies face and address the common patterns that challenge companies across the industry. Beyond this core, it’s impossible to solve every challenge or use case. Shopify provides an extensible platform for third-party developers so that everyone can contribute to the mission of making commerce better for all.