Built for serious email senders
CMass gives Claude everything it needs to write outreach that actually sounds like you — your data, your contacts, and a built-in CRM that keeps the full relationship history behind every deal.
Add to Chrome — FreeEvery list you have, in one click
Paste emails, upload a CSV, or link a Google Sheet directly. CMass auto-detects your email column and maps every other column as a merge tag automatically — {Company}, {Role}, {LinkedIn}, whatever you named it.
- ✓Google Sheets: link any sheet, no download required
- ✓CSV: drag-and-drop with instant column mapping
- ✓Paste: type or paste raw email addresses
- ✓CC and BCC columns: include stakeholders per row
An optional AI assist — off until you want it
Merge tags do the heavy lifting on personalization. If you want a little extra, flip on the optional Claude assist and it adds one tailored line per recipient from your contact data. It's off by default — most campaigns never need it.
- ✓Off by default — turn it on per campaign only when you want it
- ✓Adds one tailored sentence per recipient from your sheet data
- ✓You write the email body; Claude just adds an optional opener
- ✓Included on Pro — no separate Claude account or API key needed
I saw {company} is hiring fast right now.
I'd love to show you how CMass can help…
✦ AI Personalization
Optional — off by default
Unlimited follow-ups — and land in the right thread
Set as many follow-up stages as you need, each with its own timing, subject, and send condition. Choose how each email threads: send a campaign as a reply into your existing conversation with a contact, or give a follow-up a fresh subject while quoting the prior conversation below it.
- ✓Unlimited stages — not capped at 3 like other tools
- ✓Per-stage conditions: no reply, no open, or always
- ✓Send as replies: land in your last conversation with each recipient
- ✓Force conversation below: new subject, prior thread quoted underneath
- ✓Skip weekends option per stage
Automated stages
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 — let me know if…
See who opened, clicked, and replied
Real-time open and click tracking per recipient, per campaign. Drill into which recipients clicked which links, break performance down by recipient domain, and share a live report — all without leaving Gmail. Your own opens are filtered out so the numbers stay honest.
- ✓Per-recipient open and click counts, plus a per-link click breakdown
- ✓By-domain reporting (gmail.com vs outlook.com and more)
- ✓One-click CSV export of every recipient and their activity
- ✓Shareable public report link — live, no login, optionally anonymized
- ✓Tracker Blocker filters the sender's own opens from the totals
Q2 Outreach — May 2026
Sent May 20 · 250 recipients
250
Sent
68%
Opened
16%
Clicked
4
Bounced
Test it, then let the winner send itself
Write two variants — different subject lines, different bodies, or both. CMass sends them to a slice of your list, watches open, click, and reply rates, and after your chosen wait window automatically sends the winning variant to everyone else.
- ✓Variant A vs B — test subject lines, bodies, or both
- ✓Choose the test size; the winner goes to the remaining recipients
- ✓Winner picked by open, click, or reply rate — your call
- ✓Set it to 100% for a pure split test with no auto-send
A/B Test · Q2 Outreach
Testing 50%Quick question about {company}
{first_name} — idea for {company}
Every reply, sorted — and answered faster
When recipients reply, CMass auto-sorts them into Gmail labels and filters out auto-responders so sequences only pause for real people. The Reply Project screen gathers every reply in one place with a sentiment read and a one-click AI draft you send threaded straight back into Gmail.
- ✓Auto-labels replies in your inbox (CMass/Replies, CMass/Bounces)
- ✓Auto-responder detection — out-of-office won't stop your sequence
- ✓Reply Project: all replies on one screen with sentiment
- ✓One-click Claude draft, sent threaded into the original conversation
💬 Replies · 3 to follow up
Keep your sender reputation clean
CMass automatically tracks bounces and unsubscribes so you never email a bad address twice. List-Unsubscribe headers are added to every campaign for one-click unsubscribe in Gmail and Apple Mail.
- ✓Automatic bounce suppression across all campaigns
- ✓One-click unsubscribe (RFC 8058) in every email
- ✓Bounce and unsubscribe lists are per-account and cumulative
- ✓CAN-SPAM and GDPR compliant out of the box
Tracking
Deliverability
12
Bounces blocked
3
Unsubscribes
Add images that just work in every inbox
Upload an image straight from your device and CMass hosts it for you on a fast, permanent URL — no third-party image host, no expiring links, no copy-pasting from Imgur. Prefer to use an image you already host? Paste its URL instead. Either way, hosted images keep your emails light and your open tracking accurate.
- ✓Upload from device — JPEG, PNG, GIF, WebP, or SVG up to 5 MB
- ✓Hosted on CMass's own storage with a permanent public URL
- ✓Or paste a URL from any host you already use
- ✓Built-in sizing guidance so images stay sharp on every screen
Insert Image
Tip: export ~1200px wide for sharp results
Your logo and colors on every email
Set up your brand once — logo, primary and accent colors, font, signature, and footer. Then flip one toggle on any campaign and CMass wraps your plain email in a clean, branded HTML shell that recipients see in their inbox. No designer, no HTML.
- ✓Upload a logo and set primary + accent colors
- ✓Reusable signature and footer with one-click unsubscribe
- ✓Per-campaign toggle — branded when you want it, plain when you don't
- ✓Live preview of exactly how recipients will see it
Logo
Primary
Accent
Font
Footer
Share results with a clean, branded link
Running campaigns for clients? Pick the campaigns, give the report a title, and CMass generates a polished, shareable web page — no spreadsheet exports, no screenshots. Send the link and your client sees live opens, clicks, replies, and a per-campaign breakdown under your brand.
- ✓One shareable link — opens in any browser, no login for clients
- ✓Headline metrics plus a per-campaign and top-links breakdown
- ✓Carries your Brand Kit logo and colors automatically
- ✓One-click PDF download (Pro) — no print dialog, ready to attach
- ✓Optional per-recipient activity · revoke or expire links anytime
Report title
Client name
Include campaigns
Shareable link
One shared pool of contacts — and the history behind them
On the Team plan, everyone works from the same contact pool. It's not just a shared list — every seat sees the relationship history, scores, and campaign touchpoints contributed by any teammate. If a colleague already emailed a prospect, you know before you reach out. Invite up to 5 seats by email, and a team dashboard rolls up everyone's results.
- ✓Up to 5 seats — owner invites teammates by email, they join in one click
- ✓Shared contact pool with shared relationship history & scores
- ✓Team-wide unsubscribe & bounce suppression — one opt-out protects everyone
- ✓Team analytics — every member's campaigns in a single dashboard
- ✓2,000 emails/day, pairing naturally with Google Workspace
Acme Sales
Jordan Lee
jordan@acme.com
Sarah Kim
sarah@acme.com
Marcus Tran
marcus@acme.com
priya@acme.com
Invitation pending
4,120
Sent
61%
Open
14%
Reply
A lightweight CRM, right inside Gmail
Track deals and relationships without leaving your inbox. Build pipelines, drop contacts into records, and move them through your own stages. CMass deterministically links the right email thread to the right record by matching participants — no AI reading your mail, just a clean match on who's on the thread.
- ✓Visual pipelines with custom stages — Lead, Negotiation, Won, your call
- ✓Records hold contacts, linked email threads, tasks, and notes in one place
- ✓Auto-link: CMass suggests the record an open email belongs to and links it in one click
- ✓Reuses your existing contacts and team — shared across every seat on the Team plan
- ✓No new tab, no data export — it lives in the same Gmail sidebar
- ✓Free on every plan — including Free, for everyone, forever. No upgrade required.
✨ This email matches a record
events@hilton.com is a contact on “The Hilton.”
🔗 Link emailevents@hilton.com
ops@northwind.io
Never let a follow-up slip again
Add a follow-up to any record with a date and time, and CMass reminds you when it's due — a desktop notification plus a badge on the Chrome icon counting what's due today. A cross-record Follow-ups view rolls up everything you owe, grouped by Overdue, Today, and This week.
- ✓Date & time picker on every task — set it and forget it
- ✓Desktop notification fires exactly when a follow-up is due
- ✓Icon badge counts follow-ups due today, from any tab
- ✓Follow-ups view groups every open task across all records by urgency
Overdue
It will be after 3pm…
The Hilton · Jun 1, 10:56 PM
Today
Send revised proposal
Acme Corp · 4:00 PM
Confirm venue booking
Globex LLC · 6:30 PM
This week
Call next week
The Hilton · Thu 11:00 AM
🔔 The CMass icon shows a badge with how many follow-ups are due today.
Roadmap
Where CMass is headed
Email is just the surface. The real relationship lives in your meetings, the decks you shared, the follow-ups you promised, and the people who showed up. We're connecting all of it to Claude.
Google Calendar
Coming soonMeeting history per contact — date, duration, agenda, and whether it actually happened.
Meeting attendees
Coming soonWho was invited, who showed up, who didn't. Claude uses this to reference the right people.
Shared decks & docs
Coming soonLink a Google Drive folder. CMass knows what proposals and pitches you've shared with each contact.
Full email thread context
In progressClaude reads your email history per recipient. Coming: full thread summarization across campaigns.
Meeting notes & transcripts
PlannedConnect your recorder or notes app. Claude reads what was discussed, not just that a call happened.
External CRM sync
PlannedThe built-in CRM is live today. Next: two-way sync with Salesforce, HubSpot, and Notion so CMass records flow to the tools your team already uses.
Start with what's live today. Everything above adds to the same Claude context — no workflow change required.
CMass vs GMass
Same Gmail foundation. More power where it matters.
| Feature | CMass | GMass |
|---|---|---|
| Google Sheets mail merge | ✅ | ✅ |
| Unlimited follow-up stages | ✅ | ❌ |
| AI personalization per recipient | ✅ | ❌ |
| Arbitrary column merge tags | ✅ | ✅ |
| Bounce suppression | ✅ | ✅ |
| One-click unsubscribe (RFC 8058) | ✅ | ✅ |
| Open / click tracking | ✅ | ✅ |
| Send as replies to a prior thread | ✅ | ✅ |
| A/B testing with auto-winner | ✅ | ✅ |
| Per-link click breakdown | ✅ | ✅ |
| Domain-level reporting | ✅ | ✅ |
| CSV / data export | ✅ | ✅ |
| Auto-label replies in Gmail | ✅ | ✅ |
| Batch reply screen with AI drafts | ✅ | ❌ |
| Per-reply sentiment | ✅ | ❌ |
| Hosted image upload | ✅ | ✅ |
| Per-stage send conditions | ✅ | ❌ |
| Skip weekends per stage | ✅ | ❌ |
| CC / BCC per recipient from sheet | ✅ | ✅ |
| Branded HTML email wrapper (logo + colors) | ✅ | ❌ |
| Shareable client report links | ✅ | ❌ |
| One-click PDF export of reports | ✅ | ❌ |
| Shared team relationship history | ✅ | ❌ |
| Built-in CRM pipelines inside Gmail | ✅ | ❌ |
| Auto-link emails to CRM records | ✅ | ❌ |
| Follow-up reminders with desktop alerts | ✅ | ❌ |