I have integrated with Zoho's Oauth flow, have a valid access token and using the right scope to obtain deals data from the records api in v3:
headers: {
Authorization: `Zoho-oauthtoken ${zohoCredential.accessToken}`,
'Content-Type': 'application/json',
scope: 'ZohoCRM.modules.deals.ALL,ZohoCRM.settings.fields.ALL'
}
})