📧 Email Infrastructure

Email Deliverability Tools
Stop Landing in Spam

Quick Answer: Email deliverability tools like Instantly (8.5/10), Lemlist (8.3/10), and Smartlead (8.0/10) keep your sales emails out of spam folders. These tools provide automated warmup, sender reputation monitoring, and safe sending infrastructure. With 40% of cold emails landing in spam or promotions, deliverability tools are essential for any outreach strategy.

Perfect copy and targeting mean nothing if your emails never reach the inbox. Email providers have become sophisticated at detecting and blocking cold outreach. These tools help you maintain sender reputation, warm new domains, and send at scale without triggering spam filters.

Why Deliverability Killed Cold Email

Gmail and Microsoft control over 70% of business email. In 2024, they implemented strict anti-spam measures that specifically target cold email patterns. Understanding these changes is essential.

What Email Providers Now Detect:

  • Sending Volume Spikes: Sudden increase from new domains signals spam
  • Low Engagement: When recipients don't open/reply, future emails get deprioritized
  • Template Patterns: Similar email structures sent in bulk
  • Authentication Issues: Missing SPF/DKIM/DMARC = untrusted sender
  • Spam Complaints: Even 0.1% complaint rate triggers warnings
  • Bounce Rates: High bounces indicate purchased or scraped lists

The solution isn't to stop emailing—it's to send properly. These tools help you maintain the technical foundation that keeps your emails trusted.

Top 7 Email Infrastructure Tools (Ranked)

Tool Signal Score Pricing Best For Action
Instantly
Cold email infrastructure for agencies and teams
 8.5/10 $37/month Agencies and teams sending high-volume cold email Try Free
Lemlist
Multi-channel sales engagement with personalization
 8.3/10 $39/month Teams wanting highly personalized multi-channel outreach Try Free
Smartlead
AI-powered cold email automation
 8/10 $39/month Teams wanting unlimited mailboxes with smart sending Try Free
Mailreach
Email warmup and deliverability monitoring
 7.8/10 $25/month Teams focused specifically on email deliverability Try Free
Woodpecker
Cold email automation for B2B companies
 7.5/10 $29/month B2B companies wanting reliable email automation Try Free
Mailshake
Sales engagement platform for outbound teams
 7.2/10 $58/month Sales teams wanting email plus phone outreach Try Free
GMass
Mass email and mail merge for Gmail
 6.8/10 Free tier / $25/month Solo users wanting simple Gmail-based outreach Try Free

Ranked by Signal Score. Learn about our scoring methodology →

Detailed Tool Reviews

Instantly

8.5/10
Email Infrastructure

Cold email infrastructure for agencies and teams

Instantly provides unlimited email accounts, automated warmup, and AI-powered sending for cold email at scale. Built for agencies with white-labeling, client workspaces, and campaign analytics.

Pricing: $37/month
Best for: Agencies and teams sending high-volume cold email

Key Features:

  • → Unlimited email accounts
  • → Automated email warmup
  • → AI-powered sending optimization
Pros:
  • + Best value for unlimited accounts
  • + Strong deliverability features
Cons:
  • - No built-in prospecting database
Try Instantly Full Review

Last updated: 2025-11-16

Lemlist

8.3/10
Email Infrastructure

Multi-channel sales engagement with personalization

Lemlist combines email, LinkedIn, and phone outreach with advanced personalization including dynamic images and videos. 450M+ contact database with waterfall enrichment for accurate data.

Pricing: $39/month
Best for: Teams wanting highly personalized multi-channel outreach

Key Features:

  • → 450M+ B2B contact database
  • → Dynamic image and video personalization
  • → Waterfall enrichment
Pros:
  • + Superior personalization capabilities
  • + Multi-channel in one platform
Cons:
  • - More expensive than email-only tools
Try Lemlist Full Review

Last updated: 2025-11-16

Smartlead

8/10
Email Infrastructure

AI-powered cold email automation

Smartlead offers unlimited mailboxes, auto-rotating sending, and AI warmup for cold email campaigns. Master inbox feature unifies all conversations for easy management.

Pricing: $39/month
Best for: Teams wanting unlimited mailboxes with smart sending

Key Features:

  • → Unlimited mailboxes
  • → Auto-rotating email accounts
  • → AI email warmup
Pros:
  • + Unlimited accounts at base price
  • + Strong auto-rotation prevents spam
Cons:
  • - No prospecting database
Try Smartlead Full Review

Last updated: 2025-11-16

Mailreach

7.8/10
Email Infrastructure

Email warmup and deliverability monitoring

Mailreach focuses purely on email warmup and deliverability. Warms your inbox through real conversations, monitors sender reputation, and alerts you before deliverability drops.

Pricing: $25/month
Best for: Teams focused specifically on email deliverability

Key Features:

  • → Automated email warmup
  • → Real conversation-based warming
  • → Deliverability scoring
Pros:
  • + Specialized warmup expertise
  • + Affordable standalone solution
Cons:
  • - Warmup only, no sending features
Try Mailreach Full Review

Last updated: 2025-11-16

Woodpecker

7.5/10
Email Infrastructure

Cold email automation for B2B companies

Woodpecker provides cold email automation with strong deliverability features, condition-based campaigns, and agency features. Known for reliability and compliance focus.

Pricing: $29/month
Best for: B2B companies wanting reliable email automation

Key Features:

  • → Condition-based follow-ups
  • → Email deliverability suite
  • → A/B testing
Pros:
  • + Strong deliverability track record
  • + Reliable and stable platform
Cons:
  • - Fewer advanced features than competitors
Try Woodpecker Full Review

Last updated: 2025-11-16

Mailshake

7.2/10
Email Infrastructure

Sales engagement platform for outbound teams

Mailshake combines email outreach with phone dialer and social selling features. Data finder included for prospecting, plus lead catcher to manage replies.

Pricing: $58/month
Best for: Sales teams wanting email plus phone outreach

Key Features:

  • → Email sequences
  • → Built-in phone dialer
  • → Data finder for prospecting
Pros:
  • + All-in-one outbound platform
  • + Phone dialer included
Cons:
  • - Higher price for email-only use
Try Mailshake Full Review

Last updated: 2025-11-16

GMass

6.8/10
Email Infrastructure

Mass email and mail merge for Gmail

GMass turns Gmail into a powerful mass email platform. Send campaigns directly from your Gmail account with mail merge, automatic follow-ups, and detailed analytics.

Pricing: Free tier / $25/month
Best for: Solo users wanting simple Gmail-based outreach

Key Features:

  • → Gmail-native sending
  • → Mail merge with Google Sheets
  • → Automatic follow-ups
Pros:
  • + Simple Gmail integration
  • + Affordable for individuals
Cons:
  • - Limited to Gmail ecosystem
Try GMass Full Review

Last updated: 2025-11-16

Which Tool Should You Choose?

For Agencies → Instantly

Best if you manage multiple clients or need unlimited email accounts. Instantly's white-label features, client workspaces, and unlimited accounts at base price make it ideal for agencies. Built-in warmup means you don't need separate tools.

For Multi-Channel → Lemlist

Best if you want email plus LinkedIn automation in one platform. Lemlist's waterfall enrichment and dynamic personalization (images, videos) differentiate it from pure sending tools. Higher price justified by all-in-one capabilities.

For Value-Focused Teams → Smartlead

Best if you want unlimited mailboxes with strong features at competitive pricing. Auto-rotating sending prevents deliverability issues. Master inbox unifies all conversations. Good balance of features and cost.

For Warmup Specialist → Mailreach

Best if you already have a sending tool and need dedicated warmup. Mailreach focuses purely on email warming with real conversation-based approach. Works with any email provider. Most affordable standalone warmup solution.

For Reliability → Woodpecker

Best if you prioritize stability and deliverability track record. Woodpecker has been focused on cold email deliverability for years. Condition-based follow-ups are sophisticated. Less flashy but reliably keeps you out of spam.

For Gmail Users → GMass

Best if you're a solo user wanting simple Gmail-based outreach. No learning curve—send campaigns directly from Gmail. Affordable for individuals. Not suitable for high volume or teams, but perfect for small-scale, personalized outreach.

Frequently Asked Questions

Why do cold emails land in spam?

Cold emails land in spam due to: poor sender reputation (new or burned domains), missing email authentication (SPF, DKIM, DMARC not configured), spam trigger words, low engagement rates signaling unwanted mail, high volume from single domain, and pattern detection (Gmail/Microsoft recognize bulk outreach). Email providers learned to block mass cold email patterns.

What is email warmup and why do I need it?

Email warmup is the process of gradually building sender reputation for new or cold email accounts. Warmup tools send and receive emails automatically, creating engagement history that signals to email providers your account is legitimate. Without warmup, new accounts sending bulk email immediately get flagged as spam. Most warmup takes 2-4 weeks before you can send at scale.

How many cold emails can I send per day?

Safe sending limits depend on domain age and warmup status. New domains: 10-20 emails/day during warmup. After 2-4 weeks warmup: 50-100 emails/day. Established domains: 100-200 emails/day maximum. Never exceed 200/day per mailbox. Use multiple domains and mailboxes to scale safely. Tools like Instantly and Smartlead rotate across accounts automatically.

Do I need separate domains for cold email?

Yes, absolutely. Never send cold email from your primary business domain. If your cold email domain gets blacklisted or reputation tanks, it won't affect your main domain's ability to send to customers and partners. Buy similar domains (e.g., try-yourcompany.com, get-yourcompany.io) specifically for outreach. Budget $10-15/domain/year.

Complete Your Outreach Stack

Deliverability is the foundation. Add signal-based data and personalization for maximum impact.

📡

Signal-Based Data

Target the right prospects
💼

LinkedIn Outreach

Warm them up first
🤖

AI Personalization

Scale relevant messaging
See how these tools enable our top cold email alternatives →