These docs are for v2.1. Click to read the latest docs for v3.
improved

Envelope credits are now included in the Fetch User response

Fetch user now includes details about the envelope credits available in your developer account.

{
    "...": "..."
    "envelope_credits_available": 1760,
    "envelope_credits_consumed": 40,
    "grace_envelope_credits_available": 180,
    "grace_envelope_credits_consumed": 0,
    "...": "..."
}