Warmbly
Self-hosted cold email platform with multi-step campaigns, mailbox warmup, a unified inbox and a built-in CRM.
Campaigns, warmup pool, shared inbox and CRM on your own Docker host
Warmbly runs cold email campaigns from mailboxes you already own and warms them so they keep reaching the inbox. It suits teams that want an Instantly or Smartlead style tool on their own servers.
What it is
It sends multi-step sequences with per-mailbox caps and spacing, tracks opens, clicks and replies in one dashboard, and keeps a warmup pool of monitored mailboxes. A control plane (API, Postgres, Redis, event bus) assigns work to Go workers that send through each mailbox's own provider.
Who it's for
It suits agencies and sales teams comfortable running Docker who want no per-mailbox fees. It does not suit anyone who wants a hosted service with managed deliverability, or who cannot manage their own domains and DNS.
Key features
Multi-step campaigns
Sequences with per-mailbox caps and spacing between sends.
Warmup pool
Mailboxes warm each other from a pool of monitored accounts, not throwaway ones.
Unified inbox
Every mailbox and reply appears in one place.
Built-in CRM
Contacts, pipelines, deals, tasks and meetings sit beside the campaigns.
Reply playbooks
Visual automations with AI steps handle replies.
Deliverability tracking
Bounces, complaints, suppression and inbox placement are recorded.
Up and running in 3 steps
Our honest verdict
What's great
- Workers send through each mailbox's own provider (Gmail, Microsoft or SMTP), so throughput grows by adding workers.
- Apache-2.0 licence, so you can run and modify it commercially.
- One install script starts the whole stack with no AWS, GCP, Stripe or Kafka account.
- Includes HubSpot, Slack and Zapier integrations plus a REST API and webhooks.
Where it falls short
- You run Postgres, Redis, the API and workers yourself and handle backups and upgrades.
- Deliverability depends on your own domains, DNS and sending habits; software does not fix a poor sender reputation.
- Young project; its README tells you to read the first-run guide before self-hosting because seeded dev accounts can claim an instance.
Pricing & license
Free under Apache-2.0 when you host it yourself. A managed cloud version exists; see warmbly.com for its current plans.
Open remote AI-training roles
767 open remote AI-training roles, updated November 14, 2026; most pay $20–$175 an hour. Zekai lists them free; the application goes to the employer’s platform.
Alternatives
These reviewed AI tools do the same job instantly — from our scored directory.
Use it, or have us set it up
FAQ
Does Warmbly need a cloud account?
No. The README says it runs with no AWS, GCP, Stripe or Kafka account, using local open-source components.
Is there a hosted version?
Yes. The project also offers a managed cloud service; self-hosting with Docker Compose is free of per-mailbox fees.
Which mailboxes can it send from?
Gmail, Microsoft and SMTP mailboxes you already own.
