Can I trial either one free?

Only GMass, and it is the easiest trial in this catalog — no card, no signup form. Mailshake states plainly that payment is collected up front and offers no trial.

Which includes email warmup?

Mailshake, unlimited on every plan alongside unlimited verification and contact uploads. We found no documented warmup feature for GMass, though treat that as a gap in our verification rather than proof it lacks one.

Mailshake only. Its Sales Engagement plan bundles phone numbers, a power dialer and unlimited North American dialer minutes. GMass is email inside Gmail and nothing else.

GMass on annual billing at $20/mo against Mailshake's $25/mo billed yearly. On monthly billing they are close — $29.95 against $29 — so the annual terms are what separate them.

GMass vs Mailshake

Both of these are aimed at small teams rather than high-volume operations, and both cap out well below the unlimited-mailbox platforms. The interesting difference is what each adds beyond email: Mailshake bundles a power dialer, GMass bundles nothing but removes the platform entirely. One asks you to learn a tool, the other asks you to stay in Gmail.

GMass

Mail merge and cold email inside Gmail, as a Chrome extension.

4.2From $29.95/mo

Visit GMass

Mailshake

Email plus a built-in power dialer, aimed at small teams doing multi-touch outbound.

4.1From $29/mo

Visit Mailshake

Feature	GMass	Mailshake
Rating	4.2	4.1
Starting price	$29.95/momonthly billing; $20/mo billed annually ($249/yr)	$29/momonthly billing; $25/mo billed yearly
Free trial	Yes	No
Runs inside	Gmail / Google Workspace	—
Delivery	Chrome extension	—
Individual plans	$29.95 / $39.95 / $59.95 monthly	—
Annual discount	$20/mo billed yearly (Standard)	—
Team plans	5 → 100 users, priced per seat	—
Email accounts	—	1 (Starter) / 2 ($49) / 10 ($99)
Warmup included	—	Unlimited, all plans
Monthly emails	—	1,500 (Starter), unlimited above
Dialer	—	Sales Engagement plan
Email verification	—	Unlimited

Hands-on field test

In progress

We plan to run identical 200-contact campaigns from freshly warmed mailboxes on each platform (same copy, same sending window, same domains) and measure inbox-placement rate via seed tests, plus bounce and reply rates. Until that runs we quote no deliverability figures.

The verdict

Mailshake is the better fit if calling is part of your process — its Sales Engagement tier includes a power dialer with unlimited North American minutes, and unlimited warmup and verification come on every plan. GMass is cheaper on annual billing and vastly easier to evaluate, since Mailshake collects payment up front and offers no trial at all. Neither is built for scale: Mailshake caps mailboxes tightly, GMass ties you to one Google account.

Choose GMass if you want to start today from Gmail with no card, no signup and no new interface. Choose Mailshake if your outbound mixes email and phone, and you want warmup and verification included without watching a credit balance.

Visit GMass Visit Mailshake

GMass vs Mailshake: FAQs

Can I trial either one free?: Only GMass, and it is the easiest trial in this catalog — no card, no signup form. Mailshake states plainly that payment is collected up front and offers no trial.
Which includes email warmup?: Mailshake, unlimited on every plan alongside unlimited verification and contact uploads. We found no documented warmup feature for GMass, though treat that as a gap in our verification rather than proof it lacks one.
What about calling?: Mailshake only. Its Sales Engagement plan bundles phone numbers, a power dialer and unlimited North American dialer minutes. GMass is email inside Gmail and nothing else.
Which is cheaper?: GMass on annual billing at $20/mo against Mailshake's $25/mo billed yearly. On monthly billing they are close — $29.95 against $29 — so the annual terms are what separate them.

Comparing more than two?

Put GMass, Mailshake and up to two others side by side on price, mailboxes, warmup and trials.

Open the comparison table →