Prosper Investor API Overview

The Prosper Investor APIs allow you to develop an investment client to search for, browse and invest in loan listings, and to view loan and borrower payment dependent note (“Note”) investments. The APIs utilize JSON over HTTPS and follow RESTful practices where each call retrieves a set of resources.

Prosper provides the following Investor APIs:

  • accounts – View Prosper account information, including your current cash balance.
  • listings – Retrieve active loan listings for suitable loans to invest in. Retrieve listings that you have invested in.
  • loans – View your investments in loans.
  • notes – View Notes you own. A Note is issued to you by Prosper and is dependent for payment on payments received by Prosper on a corresponding Borrower loan.
  • orders – Create an order to purchase Notes.
  • payments – View the payment history on a single loan, or a list of loans that you own.

Note: Borrower attributes for co-borrower loans correspond to the Specified Applicant, unless otherwise noted (i.e. combined debt-to-income radio, combined stated monthly income).

Developing your client

When developing your client, you will be developing directly on Prosper’s production environment. All orders that you submit are live and will be executed using your own investment funds.

Throughout the documentation, you will see references to a <prosper_base_address>. This is the base URI to all Prosper resource calls via our APIs.

For most APIs, including our security API for requesting access/refresh tokens, the <prosper_base_address> is
The exception to this is the listings API, where the <prosper_base_address> is

Prosper API Security

Prosper takes the security and integrity of user accounts and personal information seriously. In order for your apps to access Prosper member data or to act on their behalf, the app must be authorized. To ensure data integrity, our APIs use the industry standard OAuth 2.0 protocol for authorization over SSL.

There are two types of client apps you can develop for Prosper investing. Each client type requires a different security flow. These flows are discussed in more detail in Authenticating with OAuth 2.0. However, it is important that you know which client type you have developed when you register your app.

Institutional or Personal investment clients

If you are developing an institutional investment client or a client to invest on your own behalf, the authorization process is fairly direct: You will use your client id/secret and your Prosper account username and password to authorize your client and obtain an access token for making calls to Prosper APIs for account resources.

Third party investment clients

A third party investment client makes Prosper API calls on behalf of a registered Prosper user.

If you are developing a third party investment client, we require that Prosper users grant access to your application through a Prosper login process. When a user wants to grant account access to your client, you will direct to our site for permission. Once access is granted, you will receive an authorization key that uniquely identifies your client and the user when making calls to the Prosper APIs. You will use this authorization key to obtain an access token for making calls to Prosper APIs for account resources.

Note: You must be a registered third party agent (such as a Broker or Registered Investment Advisor) to create a third party investment client. If you are choosing this option, please contact the Prosper capital markets team at [email protected] to apply for this type of Prosper account prior to registering your app. We must set your Prosper account to a third party agent account.

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