Cold email outreach that runs on your server, not someone else's.
SubsiMail is a self-hosted sequencing tool. Your prospect list, your templates, and your connected inboxes live in your own database — we can't read them, can't sell them, and can't lock you out. No per-seat pricing. No content review. No account bans.
Your list is yours. We can't see it — by design.
Every hosted outreach tool asks you to upload your prospect list to their servers. Then they get acquired, leak a database, or quietly train on your data. SubsiMail runs entirely on your machine. The only network call it ever makes to us is a license check — your key and a random install ID. Nothing else. Not your contacts, not your emails, not your reply data.
No third party holds your prospects
Your contacts sit in a SQLite file on your server. We have no copy, no access, and no way to hand it to anyone.
Your inbox stays your inbox
You connect Gmail, Outlook, or SMTP directly. Mail flows through your account — no shared relay reading your outbound.
You're the data controller
For GDPR, CCPA and similar law, the contact data never leaves your control. No vendor DPA to chase.
No lock-in, ever
Cancel your license and the app keeps your data intact. Export contacts to CSV any time. It's your database.
Write what you want. Send to whoever you want.
Hosted platforms review your templates and block anything that looks "too promotional," and they ban whole industries outright. SubsiMail never inspects your content and has no prohibited-industry list. Your sending limits are the ones your own email provider sets — nothing more.
Industries commonly rejected by hosted outreach tools — all fine here. You're responsible for sending lawfully; we don't get a veto.
Why self-host
Your own sender reputation
You send through your own connected inbox — no shared IP pool, so your deliverability never suffers for another tenant's spam.
Predictable, flat cost
You pay per connected inbox, not per seat and not per contact. Add your whole team without the bill moving.
No external uptime dependency
Your sequences don't pause because a SaaS provider had an outage. It's your server, your uptime.
Runs anywhere
One container on Docker, Linux, or Windows. A $5/month VPS handles most teams.
One tenant: you
No shared sending pool, no noisy-neighbor throttling, no landing on a blocklist because of someone else's campaign.
Upgrade on your schedule
New versions are a docker compose pull. No forced migrations, no feature you depend on getting deprecated out from under you.
See the product
Same core workflow as the hosted tools you already know.
Everything a cold-email tool needs
Multi-step sequences
Threaded follow-ups that land as one conversation, not disconnected emails.
Connect your own inboxes
Gmail, Outlook, or plain SMTP/IMAP — bring your own connection, no shared sending infrastructure.
Open & click tracking
Per-contact event history, dashboard drill-down, no black-box analytics.
Reply detection
Sequences stop automatically the moment a contact replies.
Contact lists & custom fields
CSV / Excel import, segment by list, merge-tag anything you track.
Sending limits & safety
Daily caps and randomized send intervals per account, built in.
Suppression lists
Global unsubscribe and do-not-contact handling across every campaign.
Webhooks & roles
Fire events to Zapier, Make, n8n or your CRM. Unlimited team members with prebuilt roles.
Full REST API
Every action in the UI has a JSON endpoint. Drive campaigns, contacts and lists from n8n, a cron job or your own backend — authenticate with a personal API key.
Per-resource sharing
Everything's team-visible by default, or scope a campaign, contact or template to just the people who should see it — enforced everywhere, UI and API.
Audit trail & archiving
Every change records who, when and from where. Nothing is ever hard-deleted — archive or soft-delete, restore later.
Sending calendar
Per-campaign send windows and time-zone-aware scheduling, so mail goes out in business hours.
SubsiMail vs. a hosted outreach tool
| SubsiMail | Hosted SaaS | |
|---|---|---|
| Where your prospect list lives | Your server only | Their servers |
| Can the vendor read your emails | No | Yes |
| Content / template review | None | Automated + manual |
| Prohibited industries | None | Long list |
| Account can be suspended | No | Yes, at their discretion |
| Pricing model | Flat, per connected inbox | Per seat + per contact |
| If you stop paying | App keeps your data, export any time | Data held hostage / deleted |
| Sending IP | Your own inbox | Shared pool |
Deploy in 3 steps
Sign up
Free forever for your first connected inbox. Grab your license key.
Deploy
docker compose up on your own server. One container, one command.
Connect & send
Connect an inbox, write your sequence, enroll a list, go.
Not technical? We'll set it up for you.
One-time $50 and we deploy SubsiMail on your server, connect your first inbox, and hand it over running. After that there's nothing to maintain but docker compose pull.
Runs on your stack
Same build everywhere — one self-contained binary, or the Docker image.
Docker
One image, docker compose up. The recommended way to run and update.
Linux
Single static binary, x86-64 and ARM. No runtime to install, no dependencies.
Download for Linux Linux setup guideWindows
Standalone .exe. Double-click to run, or install as a service.
Pricing
Pay for connected inboxes, not seats. Every plan includes every feature.
Enterprise
Large organizations
Custom
51+ connected inboxes
- Unlimited team members, always — you only pay per connected inbox, never per seat
- Unlimited sends and contacts on every plan, including Free
- Prebuilt roles (Super Admin, Admin, Manager, View Only) included on every plan
- Webhook delivery and a full REST API on every plan — wire SubsiMail into n8n, Zapier, Make, your CRM, or your own code
No risk: cancel any time and the app keeps running on your server with all your data. Paid plans come with a 14-day refund — if it's not for you, email us and we'll return it, no questions.
FAQ
What does self-hosted mean for my data?
SubsiMail runs entirely on your own server. The only thing that ever leaves it is a periodic license check — your license key and a random install ID. We never see your emails, contacts, campaigns, or reply data. There is no "our copy" of anything.
Does self-hosting hurt my deliverability?
No — and this is a common misunderstanding. SubsiMail doesn't send from your server's IP. It relays through your connected Gmail, Outlook, or SMTP account, so recipients see that provider's reputation, exactly like a hosted tool relaying through the same account. What still matters is your own sending discipline: a warmed domain, sane daily caps (built in), and a clean list. SubsiMail handles pacing and reply-stop; domain warmup is on you.
I'm not technical. Can I still run this?
Yes. If you can copy-paste one command you can run it — the Docker guide walks through it. If you'd rather not, pay a one-time $50 and we'll deploy it on your server and hand it over running. After that, updates are a single docker compose pull.
What server do I need?
Anything that runs Docker. A $5/month VPS is enough for most teams. One container, one small database file.
What happens if I cancel, or if SubsiMail the company disappears?
The app is on your server, so it keeps running. Your data stays intact and you can export contacts to CSV any time. A lapsed license limits new sending, not access to what you already have — and because you host it, no one can switch it off remotely.
Is cold email legal?
B2B outreach is legal in most places when you follow the local rules — accurate headers, a real physical address, and a working opt-out (CAN-SPAM in the US; GDPR/PECR add consent and legitimate-interest requirements in the EU/UK). SubsiMail gives you suppression lists and unsubscribe handling; staying compliant is your responsibility, not ours to police.
Do you offer a hosted version?
Not today — self-hosting is the whole point of the product. If running your own server is a dealbreaker, the $50 setup service is the middle ground.
How is this different from Mailshake or Instantly?
Same core workflow — sequences, follow-ups, tracking, reply detection. The difference is ownership: they're hosted SaaS that store and read your outbound mail, price per seat, review your content, and can suspend you. SubsiMail is software you run, with none of that.