Mailshake vs Instantly: Paid Seats or Unlimited Mailboxes

The short answer: if one person sends from two mailboxes to a list of more than 1,000 people, or your sellers want to phone North American prospects from the same tool, Mailshake fits: its $49 Email Outreach plan caps neither sends nor contacts, and the $99 Sales Engagement plan adds a power dialer. From four mailboxes up, Instantly costs less: two Mailshake seats at 2 x $49 = $98 already pass its $97 Hypergrowth tier, which connects unlimited accounts.

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What Mailshake changes, set against Instantly, is the unit on the invoice. On Mailshake you buy users, and each paid user unlocks a fixed number of sending addresses. On Instantly you buy a volume of emails and contacts, and the mailbox count is yours. Most of what follows comes from that.

What decides it:

1. Mailboxes first, plans second. For example, a list of 4,000 prospects on a three-step sequence is 12,000 emails a month. Over 22 weekdays that is 545.5 a day, and at the 30 campaign emails per account that Instantly's limits article recommends, 545.5 / 30 = 18.2, so 19 mailboxes.
2. Price those mailboxes on each meter. Mailshake's billing article allows two mail accounts per paid user on Email Outreach, so 19 mailboxes means 10 users: 10 x $49 = $490 a month. Instantly's Hypergrowth plan connects all 19 for $97, per its pricing page. With two mailboxes the order flips: one Mailshake user at $49 sends without a monthly cap, while Instantly's $47 Growth plan stops at 5,000 emails and 1,000 uploaded contacts.
3. Start from the stack you already run. If deals live in Salesforce, Pipedrive or HubSpot, Mailshake connects to all three from Email Outreach, per its pricing page. Instantly has its API on every plan and webhooks from Hypergrowth, per its pricing file.
4. Decide now what you will check in week four. Replies and bounces per mailbox, not per campaign. Instantly's readiness article wants a warm-up health score above 90% before launch; keep reading it afterwards, on either tool.

What each one sells you

Where they part ways

One meters people, the other meters volume

Mailshake's pricing FAQ is candid about the seat meter: you may pay for three users with one person on the team, just to connect three mail accounts. So mailbox count drives the bill. On Instantly mailboxes are free to add and the caps sit elsewhere: Growth holds 1,000 uploaded contacts, so a 4,000-person list pushes you to Hypergrowth before you send one extra email, per its pricing page. Team logins have a gate too: the workspace article offers member invites on Hypergrowth and Light Speed only.

The phone

Mailshake's Sales Engagement plan, $99 a month or $85 billed yearly, adds a power dialer, phone scripts, five numbers and unlimited free minutes to North American numbers, per its pricing page. Instantly's pricing lists no calling at all. For a seller in Europe, the free minutes cover only the North American part of the call list.

Getting in, and getting out

Mailshake collects payment upfront, does not refund a cancelled period, and deletes campaign data 30 days after the subscription expires, per its billing article. Instantly deletes a trial account that is never upgraded, per its trial article. Either way, keep your own copy of the list and the sequence.

The bill for three team shapes

Prices in USD on monthly billing, checked on 24 October 2026 on the Mailshake pricing page and the Instantly pricing page. Billed yearly, Mailshake's plans fall to $25, $45 and $85 a month, and Instantly's to $37.6, $77.6 and $286.3.

Try it before either one is paid for

Instantly's trial is a free test that is enough on its own: two mailboxes, 250 leads, 1,000 campaign emails, 100 credits and two inbox placement tests, per its trial article. That checks your DNS, your copy and where the first messages land. Mailshake has no equivalent; the free route there is the live demo and the SHAKEspeare generator.

Mailshake's homepage carries a "Try for free" button, and it opens that generator, not the sender, while the pricing FAQ says there is no free trial. A homepage is written to win the click; the terms live in the FAQ.

One step an AI can take, with a person on it

On Instantly, the AI Reply Agent has a Human-in-the-Loop mode: the agent drafts each answer, and a person edits and approves it before it sends. Autopilot, which skips approval, needs Hypergrowth or above. Every generated reply costs 5 credits, sent or not, so set the agent's monthly credit budget. For example, 200 replies a month is 200 x 5 = 1,000 credits, inside the 1,500 of the $47 Growth Credits plan in the pricing file. Watch the resolution rate, the share of drafts sent unedited, before letting it send alone.

On Mailshake the AI step sits earlier. SHAKEspeare writes a six-email sequence from your homepage and results, and Mailshake's help calls the output first drafts to review. A person rewrites each email before pressing Import to Mailshake.

Choose Mailshake if your job is

• Working a big list slowly from one or two mailboxes, where an uncapped seat beats a contact cap.
• Calling North American prospects from the same screen as your emails.
• Getting a small sales team sending on day one, with CRM sync built in.

Choose Instantly if your job is

• Spreading volume across more than a handful of mailboxes, where paying per user stops adding up.
• Testing setup and copy for 14 days before any money moves.
• Handling a heavy reply load with an agent drafting and a person approving.

FAQ

Why does Mailshake list 10 addresses on one page and 5 on another?

The Sales Engagement card on the pricing page lists 10 addresses per account; the billing article allows five mail accounts per paid user and shows two users connecting ten. Read it as five per user, and confirm with Mailshake before buying for a set mailbox count.

What happens when an Instantly account passes 5,000 emails?

No overage is billed. The pricing file says you move up a tier instead, so from Growth the next step is Hypergrowth at $97 a month.

Can Mailshake send through Outlook or SMTP mailboxes?

Yes, along with Gmail and Google Workspace. Mailshake caps Microsoft and SMTP sending at 1,000 emails a day per mailbox and holds up to 5,000 prospects in one campaign, per its sending limits article.