Fact sheet · Outreach & cold email
Warmbly
Open-source cold email and warmup platform
Warmbly is an open-source platform for cold email that warms mailboxes, sends campaigns, and centralizes replies. Run it on the cloud or self-host.
Overview
Warmbly is an open-source platform for cold email and mailbox warmup. Users connect Google Workspace, Microsoft 365, or SMTP/IMAP accounts, then Warmbly gradually increases sending volume to establish sender reputation. The platform sequences campaigns with A/B testing, gathers all replies in one inbox with automatic labeling, and tracks deliverability across Gmail, Outlook and Yahoo. Every mailbox has per-mailbox safety caps and the platform includes a CRM, integrations, and automations that trigger on replies or events. The entire codebase is available on GitHub under Apache 2.0, and can be self-hosted or run on Warmbly Cloud.
Feature facts
- Mailbox warmup with automatic reputation building
- Campaign sequences with A/B testing
- Unified inbox with reply classification
- Deliverability tracking and inbox placement tests
- Automation workflows with conditional logic
- Per-mailbox safety caps and throttling
Pricing
Pricing model: Freemium
Follow Warmbly: their milestones, new launches and awards come to you by email, once a day by default.
Warmbly specifications
| Section | Outreach & cold email |
|---|---|
| Founded | 2024 |
| Origin | London, United Kingdom |
| Stage | Startup |
| Website | warmbly.com |
| Votes2 | 0 |
Warmbly metrics
| Metric | Value |
|---|---|
| Domain Rating | 26 no change since last check |
| Trust Flow | 0 no change since last check |
| Citation Flow | 28 no change since last check |
| Referring domains | 44 no change since last check |
| External backlinks | 308 no change since last check |
Fact: Ahrefs Domain Rating checked 12 Nov 2026, fact changed 1 Nov 2026. Fact: Majestic checked 1 Nov 2026, fact changed 1 Nov 2026. Link facts from Majestic. Trust Flow, Citation Flow and Topical Trust Flow are trademarks of Majestic-12 Ltd.
Warmbly domain fact sheet
Open the fact sheet
| Domain age | 1 year |
|---|---|
| Registered | |
| Expires | |
| Registrar | Cloudflare, Inc. |
| DNSSEC | Not signed |
Warmbly launch receipt sheet
What we have measured for Warmbly since it went live on SaaS Directory Info on 1 November 2026.
- 26 Domain Rating (Ahrefs) no change since launch
at launch: 26 (1 Nov 2026); latest: 12 Nov 2026 - 0 Trust Flow (Majestic)
first measured 1 Nov 2026 - 44 Referring domains (Majestic)
first measured 1 Nov 2026
Day 10 since launch. Next receipt: day 30, 1 Dec 2026. The figures report a change; they do not say what caused it, and many things can. No figure here is a guess.
Got a launch coming up?
Step-by-step tips for before, during and after your launch, free to read on SaaS Directory Info.
- Prepare
- Launch day
- Launch week
- Next steps
Compare and explore
Frequently looked up
- Q1Do you charge per email sent?
- No. Each plan includes a daily send budget. Unused volume doesn't carry over to the next day.
- Q2Is there really no mailbox limit?
- Mailboxes are unlimited on every paid plan under fair use: one mailbox for every email a day your plan includes. If you need more, you can ask and the team usually answers within a business day.
- Q3Is there a free plan?
- Yes. A hosted workspace starts free with up to 10 mailboxes warming, no credit card and no time limit. Sending, the inbox and the CRM unlock when you pick a plan.
- Q4Can I pay yearly?
- Yes, with 20% off the monthly price.
- Q5What does self-hosting cost?
- Nothing. Warmbly is Apache 2.0 and free to run on your own servers. The only paid part is linking to the warmup pool: free for 10 mailboxes, $15 a month for unlimited.
Leave a review for Warmbly
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Warmbly has a free listing. The owner can unlock the full profile with a paid launch for $5:
- Founder story (locked)
- Milestones (locked)
- Demo video (locked)
- Dofollow website link (locked)
See also
| Product | Origin | DR1 | Votes2 |
|---|---|---|---|
 PromuAI lead generation and cold email outreach platform for B2B teams | Netherlands | 0 | 0 votes. Log in to vote for Promu in the file |
 MailQVCold email that knows when to stop, slow down, follow up, switch inboxes and back off | not stated | 0 | 0 votes. Log in to vote for MailQV in the file |
 SellbirdThe outreach platform for your AI agent | United States | 0 | 0 votes. Log in to vote for Sellbird in the file |
 ProspAI-powered LinkedIn outreach that writes personalized messages and voice notes for each prospect | not stated | 37 | 0 votes. Log in to vote for Prosp in the file |