Postbox
Long-running power-user email client, retired after its 2024 acquisition by eM Client.
About
Postbox was a desktop email client for Windows and Mac, launched at TechCrunch 50 in 2008 by former Mozilla developers and built on Thunderbird's Gecko engine. It earned a loyal following among power users for fast search, advanced filtering, response templates, a built-in calendar and task manager, and Dropbox/Evernote/Google Drive integrations.
Lifecycle note: on October 22, 2024, Postbox announced it had been acquired by eM Client, and that Postbox would no longer be sold or developed. Support ran until December 22, 2024 (help center through December 22, 2025). Existing copies keep working where the OS allows, and eM Client offered migration discounts. It is included here as a reference entry — do not start new deployments on it.
What it can do
- Fast indexed search and advanced filtering
- Response templates and quick-reply tools
- Built-in calendar, task manager, and contacts
- Dropbox, Evernote, and Google Drive integrations
- Custom themes and layouts
Setup
No longer sold; existing users can keep running it or migrate to eM Client per the vendor's migration guide.
Prerequisites
A previously purchased license; the product is discontinued.
Use cases
Works with
Trust score — 5/10
Scored 5/10 (verified tier, metrics-v1). Evidence: Launched TechCrunch50 2008; Thunderbird/Gecko-based power-user client; Acquired by eM Client Oct 22, 2024; no longer sold or developed; support ended Dec 2024; Included as a reference entry only — do not start new deployments on it. License: Proprietary (discontinued; no longer sold).
How the trust score is built
Full methodology →- Adoption · stars/downloads, log-scaled vs peers
- 4.0/10
- Maintenance · recency, releases, issue load
- 1.0/10
- Openness · license + docs
- 1.0/10
- Manual review · sanity read + red-flag check
- 6.0/10
- · Launched TechCrunch50 2008; Thunderbird/Gecko-based power-user client
- · Acquired by eM Client Oct 22, 2024; no longer sold or developed; support ended Dec 2024
- · Included as a reference entry only — do not start new deployments on it
Sources
Every fact above was checked against these sources. Where a claim comes from the provider and couldn't be independently verified, the text says so.