Choose a letter mailing service for one letter or regular post

The quick answer

Use a guest letter service for an occasional order. Use an account-based business platform for repeat documents, a bulk tool for address lists, and an API when your software needs to trigger mail.

Personal and occasional letters

For a single letter, focus on the document input, print preview, recipient country, and order total. Guest checkout can remove setup steps. PieterPost is our first pick for this task because it combines writing, uploads, preview, and international sending.

If your task is a document upload to a US recipient, a focused service such as Mail a Letter Online can also fit.

Recurring business documents

For regular invoices, statements, or notices, compare how documents enter the service. A portal may suit a small office. Email submission or an API can fit an existing system. LetterStream, DocuPost, Postal Methods, and Postalocity are business candidates in this directory.

Check account funding, permissions, templates, returned mail, and how documents are separated into individual envelopes. Confirm the postal product, rather than assuming that all business letters receive tracking.

Bulk letters and software-triggered mail

Bulk sending can mean one document sent to many addresses or many distinct documents in one batch. Those are different jobs. Check whether personalization, a recipient list, and individual document matching are supported.

For software-triggered sending, compare APIs from PieterPost, Lob, PostGrid, Click2Mail, and other listed providers. A developer account and test environment can help you validate the flow before live mail. Use the directory’s business, bulk, and API filters to narrow the list.