Development Essentials Overview

The Square Developer platform provides APIs, SDKs, and tools that developers can use to integrate with Square business solutions. Millions of sellers use Square hardware (such as Terminal and Reader) and products (such as Square Point of Sale, Square for Retail, Restaurant POS, and the Seller Dashboard) to run their business.

The developer platform supports independent and partner developers who:

  • Work in-house for a seller.
  • Offer custom applications to Square sellers directly or in the Square App Marketplace.
  • Build custom solutions for businesses as a Square Solutions Partner.

Square APIs provide payment, commerce, customer, staff, and merchant capabilities that can be used as building blocks to support a broad range of business needs and create experiences that help sellers grow their business. The developer platform also provides SDKs, tools, and other resources that help developers to build, test, and monitor their applications.

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Start developing

To build on the Square Developer platform, you need a Square account and an application.

  • A Square account represents an entity (person, business, or organization) that uses Square products or APIs to manage resources. For example, they might process payments, manage orders and inventory, and store customer data. Calls to Square APIs are made within the context of a Square account based on the access token in the request.

    An account enables access to the Developer Dashboard and other developer and seller tools. While testing, you can create resources and process payments in your own account. Later, any application fees that you collect to monetize your application are credited to your account.

  • An application stores configuration settings, such as the default Square API version used for API calls or the application ID and secret used to identify and authenticate your application in the OAuth code flow. You can access and manage settings from the Developer Dashboard.

After creating your account and registering an application, use Square developer resources to explore Square APIs and begin developing. A good place to start is API Explorer, which is an interactive tool that lets you sign in with your Square account, choose an access token, and build and send Square API requests in the Sandbox or production environment.

During development, it's also a good idea to learn about requirements for publishing your application to the App Marketplace. If you need help along the way, contact Developer Support, reach out in the forums, or join our Discord community.

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Developer resources

The following topics describe Square developer resources:

  • Get Started - Shows how to sign up for a Square account, make your first API call in the Square Sandbox, and view logs of your API calls. During the sign-up flow, Square registers an application for your account.
  • Build Basics - General design concepts and patterns that you should understand when using the developer platform.
  • Developer Tools - Detailed documentation about using Square developer tools, such as the Square Sandbox, API Explorer, and API Logs.
  • Square SDKs - Describes the backend platform SDKs for Square APIs that let you code in common programming languages.
  • Sample Applications - A list of sample applications that demonstrate how to call Square APIs, Square SDKs, or client-side payment SDKs and libraries for payment processing and other business use cases.
  • GraphQL - Lets you request exactly the data you need from supported Square graphs (such as orders, payments, catalog, and customers) with faster and more compact data transfers.
  • OAuth API - Used to request and manage permissions from Square sellers that allow an application to access resources in seller accounts.
  • Webhook Subscriptions API - Used to programmatically create and manage an application's webhook subscriptions.
  • Events API - Used to programmatically pull subscriptions.
  • Migrate from Deprecated APIs - An overview of the retirement process for Square APIs and migration guides for specific deprecated APIs.
  • International Development - Key considerations for creating applications for sellers in other countries.


In addition to platform SDKs, Square provides payment processing SDKs for online, in-app, and in-person channels.

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See also