Letter Sender vs PostalMuse
Both services print, stamp, and mail letters and postcards you create online, with no subscription and no minimum. PostalMuse also offers an API for sending from AI agents. Letter Sender is built around sending from your phone, with scheduled sends and a directory of elected officials' mailing addresses.
Which service fits your job?
Choose PostalMuse for API sending and very long letters
PostalMuse has a draft-first API, and a funded account with spending limits lets an agent handle repeat sends. It charges $0.20 for each extra black-and-white letter page, against $0.25 at Letter Sender, so very long letters can cost less there. Larger volumes are quoted individually.
Choose Letter Sender for postcards, scheduling, and certified mail
Write a letter or make a photo postcard on your phone. We print and mail it through USPS. You can schedule a send up to 60 days ahead, add USPS Certified Mail, and find an elected official's mailing address in the app. PostalMuse lists no scheduling, Certified Mail, or international mail.
Price comparison in USD
| Mail piece | Letter Sender | PostalMuse |
|---|---|---|
| One-page black-and-white US letter | $1.99 | $2.49 |
| One-page color US letter | $2.19 | $2.99 |
| Full-color 4 × 6 US postcard | $1.49 | $1.99 |
| Full-color 6 × 9 US postcard | $1.79 | $2.99 |
| Each extra black-and-white letter page | $0.25 | $0.20 |
Both prices include printing and USPS First-Class postage. A five-page black-and-white letter is $2.99 at Letter Sender and $3.29 at PostalMuse, and any black-and-white letter of up to six pages costs less at Letter Sender. For a letter over six physical sheets, PostalMuse adds $3.49 and Letter Sender adds $2.50. Check both checkout totals for your exact mailing. Prices checked November 2026.
A practical way to decide
If you want to send from an AI agent, or you mail very long letters, look at PostalMuse. If you want a photo postcard or a short letter for less, want to schedule it ahead, need certified mail, or want to write to a public official, Letter Sender may fit. Sending five or more pieces in one Letter Sender checkout gets 10% off.
Preview a letter with Letter SenderSources
Competitor details come from its published pages and can change. This comparison is independent; Letter Sender is not affiliated with PostalMuse.