Send real, printed letters by post across Europe. Requires a free account; quote before sending.
Free
One server, in email. Send real, printed letters by post across Europe. Requires a free account; quote before sending.
Send real, printed letters by post across Europe. Requires a free account; quote before sending.
The rest either hold an API key issued by the publisher or ask for nothing.
Listed without a verification tick. Read the listing before installing.