Mailroom / vs GMass
Mailroom vs GMass:
the free alternative.
GMass is the market-leading paid bulk-email Chrome extension for Gmail. It works well, has been around since 2015, and offers advanced features like email warm-up, A/B testing, and behavior-triggered follow-ups. It also costs $25–$125 per user per month and locks scheduling, open tracking, and most automation behind paid tiers. Mailroom is the free alternative for the 90% of senders who just need CSV mail merge and personalised sends.
TL;DR
Pick Mailroom if
- 300/day free forever, no credit card
- 300/day on the free tier, not a 50/day teaser
- Scheduling, open tracking and unsubscribe handling at no cost
- No Chrome extension required — works in any browser
Pick GMass if
- Email warm-up service to build Gmail sender reputation from scratch
- Built-in A/B testing on subject lines and body copy
- Behavior-triggered follow-up sequences
- 10+ years of enterprise polish and integrations
Feature-by-feature comparison
GMass is the most popular paid Gmail mail-merge extension, priced at $25–$125/mo per user, with a free tier of limited trial (50 sends/day for 30 days). GMass runs as Chrome extension that sits inside the Gmail web UI.
| Mailroom | GMass | |
|---|---|---|
| Pricing | $0 | $25–$125/mo |
| Free tier | 300/day forever | 30-day trial, 50/day |
| Schedule sends | Yes (free) | Paid only |
| Open tracking | Yes (free) | Yes |
| Click tracking | Coming soon | Yes |
| Unsubscribe + suppression list | Built in (free) | Built in |
| Mail merge tags | Yes | Yes |
| Sends from your Gmail | Yes (via API) | Yes (via extension) |
| Chrome extension required | No | Yes |
| Daily limits respected | Yes (500/2000) | Yes |
| A/B testing | No | Yes (paid) |
| Email warm-up | No | Yes (paid) |
| Auto follow-ups | No | Yes (paid) |
FAQ: switching from GMass
Is Mailroom a true GMass alternative?
For the core use case — sending a personalized bulk email to a CSV list from your Gmail — yes. Mailroom does mail merge, scheduling, open tracking, and unsubscribe handling for free. GMass adds warm-up, A/B testing, and automated follow-ups, which Mailroom does not (yet) replicate. If you only need the basics, Mailroom saves you $25–$125/month.
Does Mailroom affect my Gmail sender reputation?
Both tools send through your own Gmail account, so your reputation stays your own either way. The thing that protects it is emailing people who actually want to hear from you and honouring their unsubscribes — which is why Mailroom requires you to confirm consent before every campaign and enforces a suppression list you cannot override.
Can I migrate from GMass to Mailroom?
Yes — just export your contacts as CSV, sign into Mailroom with the same Gmail account, and upload. Mailroom doesn't import GMass-specific data like A/B test results, but your recipient list and merge fields transfer directly.
Why is Mailroom free when GMass charges $25+/month?
Mailroom is a side project — it runs on Vercel's free tier and a Supabase free tier, and the developer pays the few dollars of overage out of pocket. GMass is a venture-funded business with a 30-person team. The trade-off is honest: GMass has more features and more polish; Mailroom has the core 80% for $0.
Save the $25 and just send the email.
Connect Gmail, upload your CSV, hit send. 300 a day free.
Start with Mailroom