[kaugesaar]

This... I would gladly take the time to setup a filter that forwards all the receipts to the site.

[kiallmacinnes]

Sadly, companies seem to actively avoid this kind of integration, with the notable exception of Trip It. I suspect the thought of setting up an maintaining and inbound mail server seems harder than handcrafting integrations for every provider?

[eCa]

Just use Mailgun[1] and you get incoming mail POSTed to your server for free.

I think Sendgrid[2] offers the same too?

[1] http://www.mailgun.com/

[2] https://sendgrid.com/

[cbhl]

TripIt probably has the email forwarding for business users that have to deal with corporate policies restricting scanning of email.

But even then, TripIt also provides constant email scanning if you're too lazy to forward things to them.