Configuring OAuth for my app

safe — Tue, 21 Jul 2026 05:42:30 GMT

I need some help with configuring OAuth for my app

My sandbox application ID is:

`sandbox-sq0idb-dAG9tgZj7ah-E-RLt1-f9A`

I'm currently testing the OAuth flow in the Sandbox environment, but I'm consistently receiving a 400 Bad Request error, even though I've followed the OAuth documentation step by step.

The authorization URL I'm using is:

https://squareupsandbox.com/oauth2/authorize?client_id=sandbox-sq0idb-dAG9tgZj7ah-E-RLt1-f9A&redirect_uri=http://localhost:8787/api/square/oauth_callback&scope=MERCHANT_PROFILE_READ+PAYMENTS_READ+PAYMENTS_WRITE+CUSTOMERS_READ+CUSTOMERS_WRITE+ORDERS_READ+ORDERS_WRITE+DISPUTES_READ+DISPUTES_WRITE&session=false&state=eyJidXNpbmVzc19pZCI6ImFhM2RhMTRjLWMyN2UtNDM0ZS1hNDRjLTE1ODdkYzYwNWQ1NSIsImNvbm5lY3Rpb25faWQiOm51bGwsInJlZGlyZWN0X3VybCI6Imh0dHA6Ly9sb2NhbGhvc3Q4Nzg3L2FwaS9zcXVhcmUvb2F1dGhfY2FsbGJhY2siLCJzaG9wX25hbWUiOm51bGx9

When I open this URL in the browser, it immediately loads a white page (blank page). In the browser's developer console, I can see that the authorization request returns a 400 response.

I've verified the OAuth configuration based on the documentation, but I'm unable to determine what is causing the request to fail.

Could you please help me identify what might be wrong with my OAuth request or application configuration? If there are any common misconfigurations or additional checks I should perform, I'd really appreciate your guidance.

Thank you!

Re: Configuring OAuth for my app

lennys26 — Tue, 21 Jul 2026 12:11:05 GMT

Hi @safe . The developer end of the product has its own forum. https://developer.squareup.com/forums/

You will probably have better luck asking there