Business email on your domain. One account to thousands. On your infrastructure — or ours.
One email account on your domain for a solo operator. Provision team mailboxes and connect external Gmail or Outlook accounts as you grow. Rules and filters, signatures per account, send-as identities, and out-of-office scheduling for a professional operation. Blocked and safe sender lists enforced at the server. Email tracking. Unlimited accounts, zero per-user fees. Calisto-hosted with guided DNS — or bring your own backend. Full DKIM, SPF, and DMARC authentication.
Inbox. Starred. Snoozed. Sent. Drafts. Archive. Done.
Everything you expect from a modern email client — because you shouldn't have to relearn email. Inbox for new mail. Star what matters. Snooze what doesn't matter yet. Threaded conversations. Rich text compose with attachments and inline images. Full-text search across every account. Keyboard shortcuts for power users. The same muscle memory you already have, in a client that's part of your business platform instead of bolted onto it.
Maintenance schedule Q3
Thread View
Conversations grouped by thread. Expand, collapse, reply inline. The same threading you already know.
Compose
Rich text editor. File attachments. Inline images. CC, BCC. Reply, reply all, forward. Signature auto-insertion per account. Draft auto-save.
Snoozed
Defer an email to tomorrow morning, next Monday, or a custom date and time. It vanishes from your inbox and reappears when you’re ready for it.
Search
Full-text search across all connected accounts. Filter by sender, recipient, date range, attachment presence, read/unread status.
Keyboard Shortcuts
Navigate, archive, reply, forward, compose — all from the keyboard. Shortcut reference card available in-app.
Hosted by Calisto. Or hosted by you. Your email never has to leave your servers.
Two modes. Calisto-hosted: connect your domain, Calisto runs the mail server. Guided DNS setup generates MX, DKIM, SPF, and DMARC records — copy, paste, verify, done in under 10 minutes. Or bring your own backend: point Calisto at your existing mail infrastructure and keep every email on your servers. Your data, your compliance, your control. Either way — unlimited accounts, zero per-user fees, full authentication.
Calisto-Hosted
Calisto runs the mail server. Connect your domain with guided DNS setup. Unlimited personal and role accounts. No seat limits. No per-user charges.
Bring Your Own Backend
Run your company email on your own infrastructure. Calisto provides the client, the integrations, and the platform connection — your servers handle storage and delivery. Your email never touches Calisto's servers.
Unlimited Accounts
Personal accounts (alex@yourbusiness.com) and role accounts (support@, billing@, info@). No seat limits. No per-user charges. Add a new hire in the morning, their email is live before lunch.
Role Accounts
Shared mailboxes for departments. Multiple team members read and respond from the same address. Internal routing determines who sees what.
Sender sidebar with contact record and deal stage. Every platform email from your domain.
Two capabilities that connect email to the rest of the platform. The sender sidebar shows the contact record, deal stage, and conversation history alongside every email. The platform envelope routes every email Calisto sends on your behalf — proposals, campaigns, signatures, forms — through your domain.
Proposals. Campaigns. Signatures. Forms. Every email your clients receive comes from you.
When Calisto Proposals sends a proposal, the email comes from proposals@yourbusiness.com — not from noreply@calisto.com. When Campaigns sends a marketing email, it comes from your domain. When Sign requests a signature, it comes from your domain. When Forms sends a confirmation, it comes from your domain. Your clients always see your name, your domain, your brand. One mail infrastructure powers every outbound email across the entire platform.
Proposals
Proposals sent via email arrive from your domain. Open tracking, view analytics, and follow-up sequences — all from your business email.
Sign
Signature requests sent from your domain. The recipient sees your name, not a third-party e-signature service.
Campaigns
Marketing emails and newsletters sent from your domain with full DKIM authentication. Deliverability built on your domain's reputation.
Forms
Form submission confirmations and notifications from your domain.
Deals
Deal-related emails — follow-ups, quotes, stage notifications — from your domain.
Signatures per account. Rules and filters. Blocked and safe senders. Out of office. Email tracking.
Five configuration surfaces. Signatures with rich text, images, and links per account. Rules and filters with multi-condition matching and automated actions — forwarding, labeling, archiving, deleting. Blocked and safe sender lists enforced at the mail server via Sieve. Scheduled out-of-office auto-reply with date ranges. Email tracking with open and click monitoring.
Signatures per account. Auto-responders that run without you.
Rich text email signatures with formatting, images, and links. Create multiple signatures per account — one for first contact, one for internal, one for mobile. Auto-responders handle vacation replies, after-hours messages, and custom triggers. Set a date range, write the message, forget about it.
Maria Chen
Operations Manager, Resort Alma
+1 (555) 234-5678
resort-alma.com
Signatures
Rich text with logo, phone, title, social links. Multiple signatures per account. Default signature per account type. Switch when composing.
Auto-Responders
Vacation replies with date range. After-hours messages with schedule. Custom triggers for specific conditions. Fires once per sender per activation period — not an infinite reply loop.
Filters. Forwarding rules. Blocked senders. Your inbox, your terms.
Rule-based inbox automation. Filters match by sender, recipient, subject, keywords, or headers — then label, archive, star, move, or delete automatically. Forwarding rules copy or redirect messages to external addresses. Block individual senders or entire domains. Server-level spam filtering catches unwanted mail before it touches your inbox.
Filters
Multi-condition rules with priority ordering and first-match logic. Actions: label, archive, star, mark read, move to folder, delete. Build once, run on every incoming message.
Forwarding Rules
Forward copies (keep original in your inbox) or redirect entirely (bypasses your inbox). Conditional rules based on sender, subject, or keywords.
Blocked Senders
Block email addresses or entire domains. Blocked messages silently discarded — no inbox, no spam folder, gone.
Spam Protection
Server-level filtering before delivery. 30-day spam retention. Train the filter with mark-as-spam and not-spam actions.
DKIM. SPF. DMARC. Three protocols that keep you out of spam.
Email authentication is invisible when it works — and catastrophic when it doesn't. Calisto configures all three protocols during domain setup. DKIM signs every outgoing email cryptographically. SPF tells receiving servers which mail servers are authorized for your domain. DMARC enforces the policy. The guided wizard generates the exact DNS records — copy, paste, verify. No manual key generation. No guessing at syntax.
Domain Authentication
DKIM
Cryptographic signing on every outgoing email. Receiving servers verify the signature to confirm the email wasn’t altered and actually came from your domain.
SPF
DNS record authorizing your mail servers to send on behalf of your domain. Prevents spoofing.
DMARC
Policy that tells receiving servers what to do with emails that fail DKIM or SPF — monitor, quarantine, or reject.
Guided DNS Setup
Calisto generates the exact TXT and CNAME records. Copy, paste into your registrar, hit verify. Under 10 minutes from start to authenticated email.
Inbox. Accounts. Rules. Signatures. Sender sidebar. Platform envelope. Deliverability.
High-Performance Ops. Zero Monthly Overhead.
Get all 15 Core modules at no monthly cost. You only pay 2% of processed revenue.