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Average Ratings 0 Ratings

Total
ease
features
design
support

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Write a Review

Description

Stop missing out on deals during the crucial two-hour gap between when a lead replies and when you respond. ColdStack consolidates all cold email replies from platforms like Instantly, Smartlead, and EmailBison into one dedicated Slack channel, allowing your team to view and take action without delay. Each response generates an instant notification complete with comprehensive engagement details, including who opened the email, the timing, and the frequency of views. Your team can efficiently reply within Slack, while ColdStack ensures that all interactions are synchronized bidirectionally with your original platform, eliminating the hassle of switching between various dashboards, Gmail, and Slack. Designed specifically for cold email agencies and sales teams that operate within Slack, ColdStack also offers mobile compatibility through Slack's app for seamless communication on the go. This integration enhances your workflow and maximizes your response rate, ensuring that no opportunity slips through the cracks.

Description

SubsiMail is a platform for self-hosted cold email sequencing, allowing users to manage prospect lists, templates, connected inboxes, and all campaign-related data directly within their own database rather than relying on a third-party SaaS solution. Designed as an alternative to platforms like Instantly, Smartlead, lemlist, and Apollo, it offers flat pricing based on connected inboxes instead of per-seat charges, ensuring complete ownership and export of data without any content review processes or external access to contacts and campaigns. The application operates seamlessly as a single Docker container on any $5 VPS, enabling users to connect to Gmail, Outlook, or any SMTP/IMAP inbox, create multi-step email sequences that incorporate merge fields and reply detection, manage user roles (admin, manager, view-only) while maintaining a comprehensive audit trail, and utilize integration through a REST API secured by personal API keys. Furthermore, the initial connected mailbox comes with a perpetually free option, making it an attractive choice for individuals and businesses alike. This unique setup empowers users with greater control over their email marketing campaigns while simplifying the management process.

API Access

Has API No 

API Access

Has API No 

Screenshots View All

No images available

Screenshots View All

No images available

Integrations

Gmail Yes 
Microsoft Outlook No 
Slack Yes 

Integrations

Gmail Yes 
Microsoft Outlook Yes 
Slack No 

Pricing Details

No price information available.
Free Trial No 
Free Version No 

Pricing Details

Free (paid plans from $49/mo)
Free Trial No 
Free Version Yes 

Deployment

Web-Based Yes 
On-Premises No 
iPhone App No 
iPad App No 
Android App No 
Windows No 
Mac No 
Linux No 
Chromebook No 

Deployment

Web-Based No 
On-Premises Yes 
iPhone App No 
iPad App No 
Android App No 
Windows No 
Mac No 
Linux Yes 
Chromebook No 

Customer Support

Business Hours No 
Live Rep (24/7) No 
Online Support No 

Customer Support

Business Hours No 
Live Rep (24/7) No 
Online Support Yes 

Types of Training

Training Docs No 
Webinars No 
Live Training (Online) No 
In Person No 

Types of Training

Training Docs Yes 
Webinars No 
Live Training (Online) No 
In Person No 

Vendor Details

Company Name

ColdStack.co

Founded

2025

Country

United States

Website

www.coldstack.so/

Vendor Details

Company Name

SubsiMail

Founded

2026

Country

India

Website

subsimail.com

Product Features

Product Features

Email Marketing

A/B Testing No 
Artificial Intelligence No 
Auto-Responders No 
CAN SPAM Compliance No 
Customer Surveys No 
Drip Campaigns No 
Dynamic Content No 
Event Triggered Email No 
Image Library No 
Landing Pages/Web Forms No 
Mailing List Management No 
Mobile Optimized Emails No 
Reporting/Analytics No 
Subscriber Management No 
Template Management No 
WYSIWYG Email Editor No 

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