Give Your Sim Studio Agent an Email with Lumbox

Originally published at lumbox.co

Sim Studio's pitch is speed: build a working agent by dragging blocks instead of writing loops. It works — until your agent needs to sign up for anything. Visual builders are great at orchestrating steps but they can't see past the verification wall without an email primitive.

The Lumbox block

Sim Studio exposes HTTP blocks for any REST API. Lumbox becomes three blocks:

• Create inbox → POST https://api.lumbox.co/v1/inboxes → output: inbox_id, address
• Wait for OTP → GET https://api.lumbox.co/v1/inboxes/{id}/otp?timeout=120 → output: otp
• Send email → POST https://api.lumbox.co/v1/inboxes/{id}/send

A complete signup flow in blocks

• Create inbox block at the top of the flow
• Feed address into the Browser automation block that submits the signup form
• After form submission, call Wait for OTP with the inbox_id
• Pipe the returned otp into the next browser block to complete verification

Why this beats shared Gmail in a visual tool

Sim Studio flows are often deployed in parallel — multiple concurrent executions of the same template. Shared Gmail means multiple OTPs collide in one inbox. Lumbox gives each execution its own inbox automatically, with zero collision risk. lumbox.co — grab a key, paste it in Sim Studio, ship.