Best eCommerce APIs in 2026: 23 APIs for Developers, by Use Case

Best eCommerce APIs in 2026: 23 APIs for Developers, by Use Case

01Introduction

An eCommerce API is an interface that lets your code read and change store data, or call a store function, over HTTP. Store platform APIs (Shopify, WooCommerce) manage products and orders, and utility APIs handle single jobs such as payments, shipping labels, currency conversion, postcode checks, and invoice PDFs.

This guide lists 23 eCommerce APIs developers use in 2026, grouped by the stage of the order they support: the store platform, customer onboarding, payments, marketplaces, shipping and fulfillment, and tax and invoicing. Each entry says what the API does and what to watch for before you integrate it. Where an API is part of the ApyHub catalog, you'll find a working request example.

Table of contents

1. What is an eCommerce API?
2. Types of eCommerce APIs
3. The 23 best eCommerce APIs at a glance
4. Store platform APIs
5. Customer onboarding APIs
6. Payment APIs
7. Marketplace APIs
8. Shipping and fulfillment APIs
9. Tax and invoicing APIs
10. eCommerce API integration: how it works
11. How to choose the right eCommerce API
12. FAQ

02What Is an eCommerce API?

An eCommerce API is a set of endpoints that exposes store data (products, inventory, customers, orders) or a store capability (payments, shipping rates, tax, validation) to other software. Your storefront, back office, mobile app, or AI agent sends a request and gets structured data back, usually JSON.

Most online stores run on a mix of these. A typical order touches a platform API to create the order, a payment API to charge the card, a validation API to check the address, a shipping API to buy the label, and a document API to send the invoice. Using APIs for each step means your team integrates a capability once instead of building and maintaining it.

03Types of eCommerce APIs

eCommerce APIs fall into six practical groups:

1. Store platform APIs manage the core store: products, variants, inventory, customers, and orders. Examples: Shopify, WooCommerce, BigCommerce.
2. Payment APIs charge customers, handle refunds, and store payment methods securely. Examples: Stripe, PayPal.
3. Marketplace APIs sync listings, stock, and orders with channels such as Amazon, eBay, and Walmart.
4. Shipping and fulfillment APIs compare carrier rates, print labels, validate addresses, and track parcels.
5. Data validation APIs check customer input (emails, postcodes, VAT numbers, bank codes) before it reaches your database.
6. Tax and invoicing APIs calculate sales tax or VAT and generate invoice documents.

From a technical angle, most of these are REST APIs returning JSON. Shopify's Admin API is primarily GraphQL, and some older marketplace integrations still use XML.

04The 23 Best eCommerce APIs at a Glance

05Store Platform APIs

Your store platform is the system of record for products, inventory, and orders. Its API is usually the first integration an eCommerce developer builds.

1. Shopify API

The Shopify API family covers store administration (the Admin API, primarily GraphQL), headless storefronts (the Storefront API), and checkout and app extensions. It's the default choice for building apps, syncing inventory, or connecting a Shopify store to an ERP or warehouse system.

Keep in mind: Shopify applies rate limits based on query cost, and throttled requests can slow a sync without an obvious error. Build in rate-limit handling from day one.

2. WooCommerce REST API

The WooCommerce REST API exposes products, orders, customers, coupons, and reports for stores running on WordPress. It's included with WooCommerce and authenticates with API keys generated in the store admin.

Keep in mind: performance depends on the merchant's hosting, so large syncs can behave very differently from one store to the next.

3. BigCommerce API

The BigCommerce API offers REST and GraphQL endpoints for catalog, orders, carts, and checkout, and it's commonly used for headless builds where the frontend runs separately from the store backend.

Keep in mind: some functionality is split between REST and GraphQL, so you may need both clients in one project.

4. Square eCommerce API

Square's eCommerce APIs combine catalog, inventory, orders, and payments for sellers who also take in-person payments through Square. One inventory count covers the physical shop and the online store.

Keep in mind: it fits best when Square is already the seller's payment and point-of-sale provider.

06Customer Onboarding APIs

Signup is the first data your store collects, and bad data here follows the customer through every later step.

5. Validate Email DNS API (including disposable emails)

Fake signups and throwaway addresses skew your metrics and waste follow-up effort. The Validate Email DNS API is an email validation API that checks whether an address is valid and deliverable through an MX record lookup. With disposable_checks set to true (the default), it rejects known disposable domains before the MX check runs. Each call costs 25 atoms.

Request:

curl -X POST "https://api.eu.apyhub.com/apyhub/verify-email-validity-and-deliverability" \
  -H "apy-token: $APY_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"email": "[email protected]", "disposable_checks": true}'

Response:

{
  "data": true
}

Keep in mind: the response is a single boolean. If you need a score or a reason for rejection, add a separate lookup.

6. RPACPC Verification APIs

RPACPC offers identity and business verification APIs for India, covering driving licence, voter ID, GST, and PAN checks. Stores and marketplaces selling in India use it for KYC on customers, sellers, or vendors.

Keep in mind: coverage is India-specific.

7. Currencies Dictionary API

International stores need a reliable currency list for price selectors and account settings. The Currencies Dictionary API returns every currency with its ISO 4217 code, English name, symbol, and emoji through one GET request, at 5 atoms per call.

Keep in mind: this is reference data. For exchange rates, use the next API.

07Payment APIs

Checkout is where the sale is won or lost, and international buyers expect to see prices in their own currency.

8. Convert Currency to Multiple Currencies API

The Convert Currency to Multiple Currencies API is a currency converter API that returns rates from one source currency to several targets in a single request. Add an optional date (YYYY-MM-DD) for historical rates; leave it out to get today's rates. Each call costs 5 atoms.

Request:

curl -X POST "https://api.eu.apyhub.com/apyhub/convert-currency-to-multiple-currencies" \
  -H "apy-token: $APY_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "source": "usd",
    "targets": ["eur", "gbp", "jpy"]
  }'

Response (each key is a source-to-target pair):

{
  "usd_eur": 0.9214,
  "usd_gbp": 0.7891,
  "usd_jpy": 161.8731257
}

Keep in mind: the API returns rates, so your code multiplies your price by the rate. A pair returns false when no rate is available, so handle that case at checkout.

9. Stripe API

The Stripe API is one of the most widely used payment APIs. It accepts cards, bank debits, and wallets such as Apple Pay and Google Pay, with SDKs for most languages and a full test mode.

Keep in mind: Stripe covers far more than payments, so scope which products you actually need to keep the integration manageable.

10. PayPal API

The PayPal API accepts payments from PayPal accounts as well as credit and debit cards. PayPal's consumer recognition can help conversion with buyers who prefer not to type in card details.

Keep in mind: most stores run PayPal alongside a card processor, which means maintaining two payment integrations.

08Marketplace APIs

Marketplaces put your products in front of an existing audience. These APIs let you manage those listings from your own systems.

11. eBay API

The eBay API lets sellers list items, manage inventory, set prices, and handle orders from their own platform, and exposes eBay's catalog for product details.

Keep in mind: functionality is spread across several APIs, so expect to integrate more than one for a full listing-to-order flow.

12. Amazon Selling Partner API

The Amazon Selling Partner API (SP-API) gives programmatic access to orders, shipments, inventory, and payments data for Amazon sellers.

Keep in mind: you need to register as a developer and complete Amazon's authorization process before making production calls.

13. Walmart Marketplace API

The Walmart Marketplace API lets approved sellers list products, manage inventory, and process Walmart orders from their own application.

Keep in mind: only approved Walmart Marketplace sellers can use it.

09Shipping and Fulfillment APIs

Delivery is the last impression a customer has of an order. These APIs help packages get labeled correctly and sent to the right address.

14. Generate QR Code API

The Generate QR Code API is a QR code API that creates codes from text, vCards, or Wi-Fi details, with optional logo overlay, colors, and error-correction level. It returns an image file or a pre-signed cloud URL, at 30 atoms per call. Stores use it for tracking links on packing slips, return labels, and product inserts.

Request (QR code with your logo, returned as a file):

bash

curl -X POST "https://api.eu.apyhub.com/apyhub/generate-qr-code/download?output=order-10482" \
  -H "apy-token: $APY_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"content": "https://yourstore.com/track/10482", "logo": "https://yourstore.com/logo.svg"}'

Keep in mind: test the logo size against your printer's resolution, since a large logo reduces how much of the code a scanner can read.

15. Generate Barcode API

The Generate Barcode API is a barcode API that produces Code128 barcodes from a text string, as a download or a pre-signed URL. Code128 suits internal SKUs, warehouse bins, and shipping labels.

Keep in mind: retail products usually need EAN-13 or UPC-A. For those, the catalog also has the Generate Simple Barcode API from Dosvak, which supports Code128, EAN-13, EAN-8, ISBN-13, and UPC-A.

16. ShipStation API (formerly ShipEngine)

ShipEngine is being renamed ShipStation API. It connects to more than 200 carriers so stores can compare rates, print labels, and track shipments. Documentation now lives at docs.shipstation.com.

Keep in mind: with the rebrand in progress, older guides and SDKs still use the ShipEngine name.

17. EasyPost API

The EasyPost API is a shipping API that gives one integration for carrier rates, label purchase, tracking, and address verification across multiple carriers.

Keep in mind: compare its carrier coverage for your shipping regions with ShipStation's before choosing.

18 and 19. Validate UK Postcodes API and Validate Indian Postcodes API

A mistyped postcode can send a parcel to the wrong depot and delay delivery by days. ApyHub has a postcode validator for each market:

• The Validate UK Postcodes API checks whether a UK postcode exists.
• The Validate Indian Postcodes API checks whether an Indian PIN code exists.

Both take a postcode string, ignore spaces when matching, return a boolean, and cost 10 atoms per call.

UK request:

bash

curl -X POST "https://api.eu.apyhub.com/apyhub/validate-uk-postcode" \
  -H "apy-token: $APY_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"postcode": "SW1A 1AA"}'

India request:

bash

curl -X POST "https://api.eu.apyhub.com/apyhub/validate-indian-postcode" \
  -H "apy-token: $APY_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"postcode": "110001"}'

Response (same shape for both):

json

{
  "data": true
}

If you ship with FedEx, the FedEx Postal Code Validation API validates postal codes across countries and returns service commitments with location details.

Keep in mind: these validators confirm that a postcode exists. To check the full address, pair them with the next API.

20. Address Validation & Location Lookup API

The Address Validation & Location Lookup API from Quadlem is an address validation API that accepts address input as query parameters or a JSON body and returns a structured validation response. It's available through the same ApyHub subscription as the postcode validators.

Keep in mind: run it at checkout, before the order is confirmed, so the customer can correct the address while still on the page.

10Tax and Invoicing APIs

Tax rules and invoice requirements vary by country, and mistakes here surface during audits.

21. Validate IFSC API

For stores operating in India, payouts and refunds need correct bank details. The Validate IFSC API checks an IFSC code and returns the bank name, branch, address, city, state, and phone. It returns false when a code is not found or has been deleted, so you can stop a payout before it fails.

Keep in mind: IFSC is India-only. For European bank details, use the Validate IBAN API or the Validate SWIFT/BIC API.

22. Validate EU VAT API

B2B stores selling in the EU need valid VAT numbers to apply the right tax treatment. The Validate EU VAT API checks a VAT number and returns a boolean. If you also need the registered company name and address, use the VAT Company Lookup API, and for bulk checks, the Validate EU VAT Batch API handles up to 10 numbers per request.

Keep in mind: validation confirms the number is registered. Your tax logic still decides how to treat the order.

23. TaxJar

TaxJar, now part of Stripe, is a tax API and platform that automates US sales tax calculation and compliance, including preparing and filing returns.

Keep in mind: TaxJar focuses on US sales tax. EU sales also need VAT handling, which is where the previous entry helps.

Bonus: Convert HTML Content to PDF API (invoice generation)

Most stores already have invoice templates in HTML. The Convert HTML Content to PDF API works as an invoice generator API: send an HTML string and get back a PDF as a download or a signed link you can email to the customer, at 50 atoms per call. If your invoice lives at a URL or in a file, use the Convert HTML to PDF API instead.

Keep in mind: the API renders what you send. Line items, tax totals, and legal fields still come from your own invoice logic.

11eCommerce API Integration: How It Works

An eCommerce API integration follows the same pattern whichever APIs you pick:

1. Map the order flow. List each step from signup to delivery and mark which ones an API will handle: account creation, address entry, payment, label creation, invoice.
2. Get credentials and test access. Create an account with each provider, generate an API key or OAuth credentials, and use the sandbox or playground to make your first calls.
3. Validate input before it's stored. Call email, postcode, address, and VAT validation at the moment the customer submits the form, so they can correct mistakes immediately.
4. Connect the system of record. Sync products, inventory, and orders between your store platform and any marketplaces or warehouse systems. Use webhooks where the platform offers them instead of polling.
5. Handle failures deliberately. Plan for rate limits, timeouts, and upstream errors. Retry transient errors with backoff, and stop retrying when the error is about credentials or balance.
6. Monitor cost and usage. Track calls per API against your plan limits, especially before seasonal peaks.

Every separate provider adds a key, a dashboard, a bill, and a renewal date. Grouping the utility APIs (validation, conversion, document generation) under one account reduces that overhead. With ApyHub, one API key and one subscription cover all the ApyHub entries in this list, with usage drawn from a shared pool of atoms. The same endpoints are also callable by AI agents through ApyHub's MCP server.

Browse the eCommerce APIs →

ApyHub doesn't replace your store platform, payment processor, or marketplace integrations. Shopify, Stripe, PayPal, and the marketplace APIs above remain the right tools for those jobs.

12How to Choose the Right eCommerce API

1. Scale under peak load. Check the rate limits and how the API behaves during traffic spikes such as sales events. An API that rejects requests at the limit forces you to build retry logic.
2. Security practices. The API should use encrypted connections and secure authentication, and the provider should state how it handles and retains customer data.
3. Integration effort. Look for request and response examples, SDKs for your stack, and a sandbox or playground to test calls before writing code.
4. Documentation and support. Documentation should be current, and there should be a clear way to reach the provider when something breaks in production.
5. Regulatory fit. Confirm the API supports the rules that apply to your store, such as PCI DSS for payment processing and GDPR for customer data in Europe.
6. Total vendor count. Count how many separate providers your store will depend on, and the cost of each, before committing.

13Conclusion

The best eCommerce API for your store depends on where you sell, how you ship, and which regulations apply to you. Start with your platform and payment APIs, since every order runs through them, then add validation, shipping, and invoicing APIs as you expand into new markets. Using APIs for these jobs keeps your team focused on the parts of the store that make it different.

Try ApyHub for free →

Built an API that eCommerce teams would use? You can publish it on ApyHub as a provider.

14FAQ

What is an eCommerce API? An eCommerce API is a set of HTTP endpoints that lets software read or change store data, such as products and orders, or call store functions, such as payments and shipping. Most return JSON.

What are the main types of eCommerce APIs? The main types are store platform, payment, marketplace, shipping and fulfillment, data validation, and tax and invoicing APIs. Most stores use several at once.

Is the Shopify API free? Shopify doesn't charge a separate fee for API access; you use it through a Shopify store or a development store created from a Shopify Partner account. Costs come from your Shopify plan and any paid apps or services you connect.

What is eCommerce API integration? It's the process of connecting your store to external APIs so tasks such as payments, address checks, shipping labels, and invoices run automatically. It usually involves getting credentials, testing in a sandbox, adding validation at checkout, and handling rate limits and errors.

Which API should I use to block disposable email signups? Use an email validation API with a disposable-domain check. ApyHub's Validate Email DNS API rejects known disposable domains by default, then verifies the domain's MX records.

Can I validate both UK and Indian postcodes with one account? Yes. ApyHub has a Validate UK Postcodes API and a Validate Indian Postcodes API, both under one subscription. Each takes a postcode string and returns true or false.

How do I show product prices in several currencies? Call the Convert Currency to Multiple Currencies API with one source currency and a list of target currencies, then multiply your base price by each returned rate. Pass a date for historical rates.

What is the best shipping API for an online store? ShipStation API (formerly ShipEngine) and EasyPost both give multi-carrier rates, labels, and tracking through one integration. Compare their carrier coverage in the regions you ship to.

How can I generate invoices automatically? Build the invoice as an HTML template, fill it with the order data, and send it to an HTML to PDF API. ApyHub's Convert HTML Content to PDF API returns a PDF file or a signed link to share with the customer.

Do I need a separate subscription for each ApyHub API? No. One ApyHub subscription covers the whole catalog, and usage from any API draws from the same atom balance.