Fastmail vs Slack
Compare Fastmail and Slack on features, pricing, and buyer fit using the same researched criteria.
Fastmail
Privacy-focused business email, calendar and contacts with custom domains and shared addresses — Business Basic from $3/user/month annual; adjacent to business communications, not a phone system.
Best for
- • Small teams that want private, independent business email on their own domain
- • Owner-operators who need shared support@ addresses and shared calendars cheaply
- • Buyers who need an email retention archive for legal compliance (Professional)
Starting from $3.00/user/mo
No free plan
VS
Our verdict
No universal winner. Choose based on which criteria matter most for your team.
Fastmail is better for
- ✓ Routing & IVR
Slack is better for
- ✓ CRM / CTI integrations
- ✓ Analytics
- ✓ AI features
Tie
- • Number / country coverage
- • Power dialer
- • WhatsApp Business
Choose Fastmail if: Small teams that want private, independent business email on their own domain
Choose Slack if: Knowledge-worker teams that need channel-based team messaging as the primary collaboration hub
Slack
Channel-based team messaging platform — Free $0, Pro $7.25/user/month annual, Business+ $15, Enterprise+ contact sales; huddles for light video, not a phone system.
Best for
- • Knowledge-worker teams that need channel-based team messaging as the primary collaboration hub
- • Organisations that want a freemium chat workspace with a deep app ecosystem
- • Salesforce-centric companies aligning chat with CRM workflows
Starting from $7.25/user/mo
Free plan available
Fastmail vs Slack pricing
Fastmail researched starting price from $3/mo. Slack researched starting price from $7.25/mo; a free plan is researched. Affiliate economics excluded.
Fastmail
From $3.00/user/mo
Slack
From $7.25/user/mo
Fastmail
Starting from $3.00/user/mo
Free trial available
- Business Basic$3.00/user/mo
- $3/user/month billed annually ($4 monthly; $36 for 12 months). 5 GB for mail, calendar and contacts plus 1 GB file storage, custom business addresses on your domain, 24/7 human support.
- mail storage gb: 5
- file storage gb: 1
- Business StandardPopular$5.00/user/mo
- $5/user/month billed annually ($6 monthly; $60 for 12 months). 50 GB mail plus 10 GB files, shared email addresses like support@, layered shared calendars, shared company address book, offline support, scheduled send and snooze.
- mail storage gb: 50
- file storage gb: 10
- Business Professional$9.00/user/mo
- $9/user/month billed annually ($10 monthly; $108 for 12 months). 100 GB mail plus 50 GB files and an email retention archive for legal compliance.
- mail storage gb: 100
- file storage gb: 50
- Individual$5.00/mo
- $5/month billed annually ($6 monthly; $60 for 12 months) for a single mailbox with premium email, calendar and contacts.
- mail storage gb: 50
- file storage gb: 10
Slack
Starting from $7.25/user/mo
No free trial evidenced
- Free$0.00/user/mo
- $0 — limited message/file history and core channel messaging. Primary evaluation path (no published free trial on paid plans).
- ProPopular$7.25/user/mo
- $7.25/user/month billed annually ($8.75 monthly). Unlimited message history, huddles, canvas and core productivity features for growing teams.
- Business+$15.00/user/mo
- $15/user/month billed annually ($18 monthly). Stronger admin, compliance and AI assistance versus Pro.
- Enterprise+Custom
- Contact sales for Enterprise+ security, compliance and large-org controls.
Estimate your team cost
Monthly estimate from verified per-seat list pricing. Confirm on the vendor site before purchasing.
Fastmail
$45.00/mo
Slack
$108.75/mo
+$63.75/mo — Slack costs more
Verified monthly unit prices · Aug 17, 2026
Prices in USD
Shown per user / month from verified list pricing.
Plans can change
Confirm live vendor rates before purchasing.
Add-ons may apply
Calling, SMS, or usage fees can add cost.
Independence
Affiliate status never changes pricing outcomes.
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