Everything MailSharks
can do

Campaigns from Gmail and Google Sheets

Bulk personalized email (mass email, cold email, mail merge) straight from your Gmail or Google Workspace mailbox. Recipients come from a plain Google Sheet: paste the link, pick the address and name columns. The service reads the sheet, drops duplicates and broken addresses, and shows the recipient count. Sending runs with pauses between messages, a daily cap and resume after a pause. Step by step in how to send a campaign from a Google Sheet.

• Sheet campaigns — send to a list with progress, pause and resume.
• Single messages — to one address without a sheet: reply, follow up, test the layout on yourself.
• Email builder — formatting, lists, images, links; or an existing Gmail draft.
• Pacing and limits — delay between messages and a daily cap to stay under Gmail limits.
• Scheduled auto-start — a campaign starts on its own at a set time, so you can prepare it in advance.
• Follow-ups — if a recipient doesn't reply within 1–3 days, the next email goes out automatically in the same thread; people who replied are excluded. Exactly how cold outreach captures most of its answers.

Personalization and variables

The subject and body support variables like {{name}} — the recipient's name from the sheet. Any column becomes a variable: city, order number, company. An empty cell becomes an empty string and the message still goes out. Personalized greetings raise open rates and cut spam complaints.

Open and click tracking

The service counts opens (open tracking) and link clicks (click tracking) per recipient and per campaign. You see who opened when and which link they clicked — open rate and click stats build in real time.

• False-open filtering — a smart filter drops mail-proxy prefetch (Gmail Image Proxy), anti-spam scanners, Apple Mail Privacy Protection and crawlers, so the open rate is not inflated.
• Per-link breakdown — see which link in the message worked.
• Who and when — tap the opens or clicks number for the list of recipients with the event time.

A/B testing the subject line

The subject line is the only thing a recipient sees before deciding whether to open the message. The service tests it with an A/B test (split test): the second subject goes to exactly half of the list, picked at random, and both halves are measured by the same statistics. The second variant can carry its own body text as well, and then both are tested at once.

• Exactly equal halves — addresses are split when the campaign is created, in pairs: every adjacent pair holds one A and one B. The halves are equal exactly rather than approximately, and a daily limit never turns the first day into a test of one variant.
• Compared by opens, clicks and replies — a metric switch, rates and absolute numbers per variant, and a curve over time.
• Significance check — the service works out whether the gap holds up or could have come out of chance at this number of messages. "B is 40% better" on ten opens is not a conclusion yet, and the screen says so plainly.
• Follow-ups remember the variant — a follow-up arrives as a reply to the message the recipient actually saw, carrying its subject.

A/B testing runs on the Pro plan; opens are tracked on both plans.

MCP server: control from an AI client

MailSharks ships an MCP server (Model Context Protocol): the service connects to Claude, ChatGPT or your own agent, and from there you run campaigns in plain words: "find the client list", "write a message about the discount", "start the campaign", "show who opened". The assistant works with the same sheets, templates and campaigns you see in the app — not a separate workspace and not a copy of your data.

• No keys to copy — you paste the address https://mcp.mailsharks.org, sign in to MailSharks and press "Allow". Nothing to store in a config file.
• Messages never go out on the model's decision — it must first prepare the campaign and show you a summary: how many addresses, what subject, how many days it takes. Sending is a second step, after you agree. That is a rule of the server, not the client's good manners.
• Your list stays yours — recipient addresses reach the model masked, in full only when you ask for it.
• Money is out of reach — paying for the plan, disconnecting Google and deleting the account stay in the app.
• Access is revoked in one tap — the list of connected clients lives in the app under Connected AI clients; a revoked connection stops working immediately.

Step by step on the MailSharks inside your AI page.

Reply inbox

Recipient replies to your campaign land in an inbox inside the app: who replied, to which campaign and what they wrote — without the quoted original. Every new reply triggers a Telegram notification, and you can reply in one tap. Replies to messages sent via the HTTP API are available programmatically too, via GET /v1/replies.

Unsubscribes and suppression lists

Unsubscribing is mandatory and immediate. There is a visible unsubscribe link in the footer and a List-Unsubscribe header for one-click unsubscribe — Gmail and Outlook render their own Unsubscribe button from it, steering the recipient away from the Spam button. People who unsubscribe go onto a suppression list and receive nothing more; the list is tied to the sheet or the account and survives campaign deletion.

Deliverability: SPF, DKIM, DMARC and spam

Whether mail lands in the inbox or in spam comes down to three DNS records. There is a guide on how to set up SPF, DKIM and DMARC from scratch and one on how to send campaigns and stay out of spam. If a domain is already blacklisted — how to get off a blacklist. Built-in tools help you check the setup (below).

Address validation: real vs non-existent

The service tells real addresses from non-existent ones before you send: it checks the format, whether the domain exists and accepts mail (MX records), finds duplicates, and reads addresses from Google Sheets people smart chips. Removing dead addresses lowers your bounce rate — and a low bounce rate is a direct sender-reputation signal and one more layer against landing in spam. More in how to stay out of spam.

Free tools

• SPF record checker — the record, DNS lookup count, extra records and errors.
• DMARC generator — build a valid p=none/quarantine/reject policy with reports.
• Email header analyzer — SPF, DKIM and DMARC checks at once from the raw message.

Gmail limits

How many messages a day you can send from free Gmail and Google Workspace, why the cap is what it is and how to stay under it — see Gmail limits in numbers. The service holds the daily cap for you so the account is not blocked.

HTTP API for developers

All of the above — from your own code. A REST API with an ms_live_… key: send single messages and campaigns, templates by number, connect sheets, statuses and events, read replies (GET /v1/replies). A separate API mailbox with its own daily cap so the integration does not eat your working quota.

Templates and drafts

Messages are saved as templates with formatting, unsubscribe and click tracking — the same for campaigns and single messages, called by a short number. You can pull in an existing Gmail draft.

Telegram bot and mini app

You work from Telegram: a bot and a mini app with screens for campaigns, sheets, templates, statistics and the reply inbox. Sign-in is via Google — the service never sees your password and access is revoked in one click in Google settings. What is requested and why is on the about page.

Pricing: free and Pro

There is a free plan with no card and a paid Pro that lifts the service's daily limits — leaving only Gmail's own quota. You pay to lift limits, not per contact. Full terms and prices on the pricing page.

How it differs and what it replaces

Unlike Mailchimp, mail goes from your own mailbox instead of a shared domain and the list stays in your sheet — compared with Mailchimp and YAMM. MailSharks is a working alternative to transport and outreach services: a Mailgun alternative, a SendGrid alternative and an Instantly alternative for people who have their own Gmail and don't need sending servers.

How to start

Connect Google, paste a Google Sheet link, write a message with a name variable and start sending — the first campaign takes about five minutes and needs no code. Open the app.

Next: campaign from a Google Sheet, how to stay out of spam, pricing and API documentation.

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