After you successfully create a Sandbox account, Dwolla will systematically create a Dwolla Balance and a bank funding source for you. 

The bank name is called the “Superhero Savings Bank” and the Dwolla Balance will have $5,000 in test funds. You can initiate transfers to or from these funding sources.

To add another bank in the Sandbox, you will need to make a request to the API.

POST https://api-sandbox.dwolla.com/funding-sources
Content-Type: application/vnd.dwolla.v1.hal+json
Accept: application/vnd.dwolla.v1.hal+json
Authorization: Bearer pBA9fVDBEyYZCEsLf/wKehyh1RTpzjUj5KzIRfDi0wKTii7DqY
{
    "routingNumber": "222222226",
    "accountNumber": "123456789",
    "bankAccountType": "checking",
    "name": "My Dwolla Master Account Bank"
}

...

HTTP/1.1 201 Created
Location: https://api-sandbox.dwolla.com/funding-sources/04173e17-6398-4d36-a167-9d98c4b1f1c3

We do not have functionality to add a bank to a Dwolla Master Account in the Sandbox dashboard at this time. 

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