5 minute read
November 30, 2022


Use Marqeta’s Core API to launch and manage your company’s payment card program.

The Core API is RESTful, so it uses HTTP methods (POST, PUT, GET) to perform functions on objects. For example, to create a new user object, you send a POST request to the /users endpoint. Some requests include data in their message body, for example to define the attributes of the object being created or updated, and the Core API requires that this data be in JSON format.

For more on reporting, see About Reporting.

Ready to start building? The Core API Quick Start includes a hands-on tutorial that helps you create the basic Marqeta platform resources.

Understanding API objects

The Core API includes objects on which you can call methods that result in, for example, issuing payment cards and customizing card behavior.

Some important Core API objects include:

  • card – represents a payment card (physical or virtual) for conducting transactions.

  • user – represents a person who uses a payment card.

  • gpaorder – used to load funds into an account.

  • fundingsource – represents the source from which a gpaorder object draws funds.

The Summary of Resources shows how the fundamental API objects interrelate.

Accessing the sandbox environment

The Marqeta platform provides a sandbox environment where you can explore the capabilities of the Core API. There are two types of sandbox environments available:

  • Public sandbox: A single-user environment where you can begin building your program. Public sandbox users are typically potential customers who are evaluating Marqeta as a partner in their application.

  • Private sandbox: A multi-user environment where you can integrate your application with the Marqeta platform. Marqeta customers use the private sandbox and its connected microservices to validate their application’s integration, as well as ongoing API changes.

All funds and transactions are simulated in both types of sandbox environments. The sandbox may give you access to features not available in production environments, depending on your integration.

The base URL for the public sandbox environment is:


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This is a private testing and development environment. For more information about exploring the public sandbox, see Core API Quick Start.

Listing endpoints

Retrieve a list of the available API endpoints by sending a GET request to the /swagger.json endpoint. For example:


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The response lists the endpoints you are authorized to access based on the credentials you provide in your request.

Using interactive widgets

Marqeta’s developer documentation includes interactive widgets that you can use to explore and test the Core API directly from your browser. After logging in to your account, you can use these interactive widgets:

  • Some pages include inline widgets for submitting API requests to specific endpoints. For example, Core API Quick Start provides a step-by-step tutorial for configuring a card and simulating a transaction with the Core API.

  • The API Explorer shows all available endpoints and operations in the Core API, grouped by object.

To use an interactive widget:

  • Log in or sign up for an account.

  • Go to a page with the interactive widget that you want to use.

  • Select the widget to expand it.

  • Select the Send request tab. The parameters and the example value in the Request Body field become editable.

  • Enter the desired parameters and request body details, and select Send request. The widget submits a request to the sandbox environment associated with your account and shows the cURL and the response.

OpenAPI UI widgets

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Accessing production environments

Each Marqeta customer who enters into an agreement to receive Marqeta’s services will access the API and operate within an individually tailored production environment called a program.

To access the API in production, use the unique base URL for your program. Be sure to update any tests or code samples with the correct base URL. For example:


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