Listed alphabetically. A tool is ranked by its reviews once it has 3.
| Tool | Reviews | Lowest paid plan | Free plan | Free trial | Public API | Runs on | Main features |
|---|---|---|---|---|---|---|---|
 Click2MailSend mail online, automate with mailing applications, or integrate with APIs. | ReviewsNone yetWrite one for Click2Mail | Lowest paid planNot confirmed | Free planNot confirmed | Free trialNot confirmed | Public APIYes | Runs oniOS, Android, Microsoft Word | Main features
|
 InkitInkit is your single system for signing, generating, and storing documents. | ReviewsNone yetWrite one for Inkit | Lowest paid plan$15per user per month, billed annuallyPersonal, as of November 14, 2026 | Free planYes | Free trialYes | Public APIYes | ||
 LobAutomate and personalize direct mail at scale with a nationwide print network. | ReviewsNone yetWrite one for Lob | Lowest paid plan$260per month plus print and postageStartup, as of November 14, 2026 | Free planYes | Free trial30 days | Public APIYes | ||
 PostalyticsDirect mail automation software. | ReviewsNone yetWrite one for Postalytics | Lowest paid plan$199per month plus per piece pricingMarketer Plan, as of November 14, 2026 | Free planYes | Free trialNot confirmed | Public APIYes | ||
 PostGridA platform and API for automating transactional mail, direct mail and address verification at scale. | ReviewsNone yetWrite one for PostGrid | Lowest paid planSee plans | Free planYes | Free trialNot confirmed | Public APIYes | Runs on | |
 Thanks.ioAutomate handwritten-style postcards, letters and gift cards with AI design, QR tracking and API integrations. | ReviewsNone yetWrite one for Thanks.io | Lowest paid plan$49per monthBusiness, as of November 14, 2026 | Free planYes | Free trialNot confirmed | Public APIYes |
From each tool's own website. “Not confirmed” means we couldn't confirm it there, not that the tool doesn't have it. Each tool's page says when its facts were checked.
How this list is made
A tool is listed here only when we've confirmed on its own website that it has a public API. Tools we couldn't confirm it for are left out, even if they may have it. Vendors can't pay for a place on this list. Add a tool we missed