Lob supports custom letter envelopes for Enterprise edition customers. However at this time, we are not able to support checks or postcards for this feature. To qualify for custom envelopes, we require a minimum envelope order quantity of 10,000 per artwork design.
To get started on custom letter envelopes, here’s a few places to look:
If you’re interested in Lob’s Enterprise edition for access to additional form factors, please reach out to our Sales team or to your current Customer Success Manager.