Email campaigns + built-in CRM
inside your Gmail
Send personalized campaigns to your whole list — and as replies come in, CMass automatically builds a contact intelligence layer on every person. Campaign history, engagement signals, AI talking points. No separate CRM. No new app. Just Gmail.
No credit card required · Works with Gmail & Google Workspace
- Follow up on Series A close
- Reference the product tour
- Intro CMass analytics to sales team
→ Auto Follow-up
Following up
Just wanted to resurface this…
Last touch
Don't want to be a bother, but…
Closing the loop
Closing this out on my end…
📅 Schedule
- Follow up on Series A close
- Reference the product tour
- Intro CMass analytics to sales team
→ Auto Follow-up
Following up
Just wanted to resurface this…
Last touch
Don't want to be a bother, but…
Closing the loop
Closing this out on my end…
📅 Schedule
What Claude knows about every contact
Campaign history
✦ LiveWhich campaign reached them, when, and how they responded
Contact data
✦ LiveEvery column from your import — company, role, custom fields
Engagement signals
✦ LiveOpens, clicks, replies, relationship score, sentiment
Thread history
Coming soonFull conversation context from every past exchange
Meeting history
Coming soonDates, duration, attendees, and what was discussed
Shared docs & decks
Coming soonProposals, one-pagers, and pitches you've sent
Claude doesn't write lines — it reasons about people
Most tools treat AI as a copywriting shortcut. CMass uses Claude as a relationship reasoning engine. It reads everything it knows about a contact — company, role, campaign history, engagement data, conversation threads — and composes a message that reflects the full picture of that relationship.
No Claude account needed
CMass has its own Anthropic API integration. Claude is built into every plan — you don't need to sign up for Claude.ai or manage any API keys.
Your campaign stats, one tab away
No external dashboards. No new tabs. The Stats tab lives right inside the CMass panel — flip to it while you're building your next campaign or after you send.
- 📤Total sent, open rate, click rate, and reply rate per campaign
- 👁️Full breakdown: opens, clicks, replies, bounces, and unsubscribes
- 🔄Live data — refresh any time to see the latest numbers
- 📋Expand any campaign row to see the detailed per-metric counts
Q2 SaaS Outreach
May 20, 2026
312
Sent
68%
Opens
19%
Clicks
8%
Replies
May Newsletter
May 12, 2026
487
Sent
44%
Opens
11%
Clicks
3%
Replies
Partner Intro Blast
May 5, 2026
95
Sent
71%
Opens
24%
Clicks
13%
Replies
Unlimited follow-up stages, on your conditions
Set as many follow-up stages as you need — each with its own timing, subject, and condition. Only email people who didn't open, didn't reply, or send to everyone. CMass handles the sequencing automatically.
- 🔁Unlimited stages — not capped at 3 like other tools
- ⚙️Per-stage conditions: no reply, no open, or always
- 📅Schedule sends with a daily limit and weekend skip
- 🧵Threaded replies stay in the same Gmail conversation
→ Auto Follow-up
Following up
Just wanted to resurface this…
Last touch
Don't want to be a bother, but…
Closing the loop
Closing this out on my end…
📅 Schedule
- Follow up on their Series A close
- Reference the product tour from last call
- Introduce CMass analytics to their sales team
Like a CRM — built into your Gmail
When someone replies to your campaign, the sidebar transforms into a full contact intelligence layer. See exactly where they came from, how they engaged, and what to say next — without opening a separate CRM.
- 🎯Campaign origin — which campaign brought them in, and when
- 📈Engagement stats — opened 3×, clicked, replied, relationship score
- 💬AI talking points — Claude suggests what to say based on your history
- ✍️One-click AI draft — generate a follow-up that knows the full story
Your campaigns convert prospects. CMass converts replies into relationships — tracking every touchpoint so you always know exactly where things stand.
Outreach that knows the whole story
Imagine emailing someone you met last week. Before you type a word, CMass already knows the meeting date, who attended, what was discussed, and the proposal deck you shared. Claude reads all of it and writes the follow-up.
What CMass will know before you send
Met with Sarah Chen on May 14th — 42 min call, 3 attendees
Sarah and Tom from Acme attended. Their VP was invited but didn't show
You shared the Q2 Outbound Playbook deck during the meeting
Sarah replied to your intro email 3 days before the call
Follow-up was promised within 5 business days — you're on day 4
✦ Claude writes
"Hi Sarah, great speaking with you and Tom last week — hope the VP got caught up on our conversation. Following up on the playbook I shared, particularly the section on automated sequences that we talked about..."
100% Built with Claude. This is where CMass is headed — start using what's live today.
Add to Chrome — FreeEverything you need inside Gmail
The complete outreach platform — import, personalize, sequence, send, and analyze — without leaving your inbox.
Google Sheets & CSV Import
Link any Google Sheet or upload a CSV. Every column becomes a merge tag — {Company}, {Role}, {LinkedIn} — auto-mapped, no setup required.
Unlimited Follow-up Stages
Build multi-stage sequences with per-stage conditions. Send only to non-openers, non-repliers, or everyone — on your exact schedule.
Hosted Image Upload
Drop an image straight from your device — CMass hosts it on a fast, permanent URL and inserts it into your email. No third-party image host, no expiring links, no broken pictures.
In-Panel Campaign Stats
A dedicated Stats tab lives right inside the CMass panel. See opens, clicks, replies, bounces, and unsubscribes for every campaign — without leaving Gmail.
Bounce & Unsubscribe Suppression
Bad addresses and unsubscribes are automatically blocked from all future campaigns. Your sender reputation stays clean without any manual work.
Lives in Your Gmail
Every email lands in your Sent folder. Replies hit your inbox. No separate portal, no third-party dashboard — CMass sits inside Gmail as a panel.
Built-in CRM with PipelinesComing soon
Track deals in visual pipelines right inside Gmail. Records hold contacts, linked email threads, tasks, and notes — and CMass auto-links the right email to the right record by matching who's on the thread. Free on every plan, including Free — for everyone, forever.
Follow-up RemindersComing soon
Give any task a date and time and CMass reminds you when it's due — a desktop alert, an icon badge counting what's due today, and a cross-record Follow-ups list grouped by urgency.
Up and Running in 5 Minutes
Install the extension, connect your Google account, import your list, and send. No complicated onboarding — just Gmail with Claude inside.
Up and running in 5 minutes
No complicated setup. No new inbox. Just Gmail — with Claude inside.
Install CMass
Add the Chrome extension — it embeds directly into Gmail as a side panel. No new app, no new inbox to manage.
Import your list
Paste emails, upload a CSV, or link a Google Sheet. Every column becomes a data point CMass and Claude can reason about.
Personalize and send
Write your email once and drop in merge tags like {first_name} and {company}. Want an extra touch? Claude can optionally add a personalized line — off by default, on when you want it.
Relationships, not just replies
Sends land in your Sent folder. Replies build contact intelligence in your sidebar. Every engagement deepens the picture CMass holds on that relationship.
Loved by senders
"I sent a campaign and got 22 replies. CMass already knew each person's history, scored the relationship, and had talking points ready. I didn't open a CRM once."
Sarah K.
Head of Growth, Fintech startup
"I sent a campaign to 90 people and 12 replied. CMass showed me exactly which campaign each person came from and suggested talking points for every follow-up. It's basically my CRM now."
Marcus T.
Founder, B2B SaaS
"The Stats tab is what sealed it. I can check how a campaign is performing without ever leaving Gmail or opening a new tab."
Priya N.
Sales Lead, Agency
✦ Relationship intelligence for Gmail
Your inbox. Your CRM. Your Claude.
Free plan includes 50 emails/day, Sheets & CSV import, AI-composed campaigns, automated follow-up sequences, in-panel analytics, and contact intelligence. No credit card needed.
Frequently asked questions
Does CMass work with my existing Gmail account?↓
Yes. CMass connects to your Gmail via the official Google API. You keep your domain, your inbox, and your sender reputation.
How is CMass different from GMass?↓
GMass is a mail-merge tool. CMass is a relationship intelligence platform. The difference: CMass builds a full contact intelligence layer on every person who engages — campaign origin, engagement history, relationship score, conversation topics, AI-suggested talking points. Claude doesn't just fill in a name; it reasons about the entire context of each relationship and composes accordingly.
Do I need a Claude or Anthropic account?↓
No. CMass has its own Anthropic API integration — Claude is built into every plan, free and paid. You don't need a Claude.ai subscription, an Anthropic account, or any API keys.
What does "powered by Claude" actually mean?↓
Claude is Anthropic's AI model — the same one behind Claude.ai. In CMass, Claude acts as a relationship reasoning engine. It reads everything known about a contact — their data from your import, campaign history, engagement signals, conversation threads — and composes messages that reflect that full context. As your history with each contact grows, so does what Claude knows before it writes.
Where do I see my campaign analytics?↓
Right inside the CMass panel — no new tabs, no external dashboard. Click the 📊 Stats tab while composing or after a campaign sends to see opens, clicks, replies, bounces, and unsubscribes per campaign.
How does the CRM feature work?↓
CMass includes a lightweight CRM inside the Gmail sidebar. Build visual pipelines, add records for each deal, and move them through your own stages. Each record holds contacts, linked email threads, tasks, and notes — and CMass auto-links the right email to the right record by matching who's on the thread (no AI reading your mail). Add a due date to any task and you get a desktop reminder, an icon badge counting what's due today, and a cross-record Follow-ups view. Separately, when a recipient replies, a contact intelligence card surfaces their history, relationship score, and talking points. No external CRM needed — it all lives in Gmail.
Is there a free plan?↓
Yes. The free plan includes 50 emails per day, Google Sheets & CSV import, merge tags, an optional Claude AI assist, and in-panel analytics. No credit card required.
Why is there a daily sending limit? Can I send more?↓
The daily sending ceiling is set by Google, not CMass. Free Gmail accounts can send up to 500 emails per day; Google Workspace accounts can send up to 2,000 per day. CMass plan limits are designed to stay within what Google allows. If you need a higher ceiling, upgrading to Google Workspace is the path — it moves you from 500 to 2,000 emails per day and pairs naturally with the CMass Team plan.
Is CMass CAN-SPAM and GDPR compliant?↓
Yes. Every campaign includes a one-click unsubscribe link. CMass automatically suppresses unsubscribes and bounces from all future sends.