Swimlanes.io is a free webapp for making sequence diagrams. You simply edit the text on the left and the diagram is updated in real time. You can download your sequence diagrams as images or distribute with a link.
title: ADR 001: Payment mechanism for credential issuance Issuer -> Holder: Credential Offer (+ payment_request) Holder -> Ledger: payment transaction (with payment_request id in memo) Ledger -> Holder: payment transaction response (with transaction_hash) Holder -> Issuer: Credential Request (+ payment_receipt) Issuer -> Ledger: Get payment transaction by hash Ledger -> Issuer: Payment transaction Issuer -> Issuer: Check `memo` field from received transaction Issuer -> Holder: Credential Holder -> Issuer: Accept