Deliverability is a focal point of every email marketing campaign, whether it's cold sales, lead nurturing, promotional emails, or newsletters. That’s why it’s arguably the most crucial email marketing metric to track. 

How you set up domains, warm-up sending accounts, write email copy, and choose leads directly affects email deliverability. To accurately monitor deliverability, you need tools that give insight into all these metrics. 

Different Types of Email Deliverability Monitoring Tools

While email deliverability tools share the common goal of getting your emails into inboxes, they tackle the problem from different angles depending on your use cases and marketing workflow.

Let's take a look.

Pre-Send Testing Tools

These focus on catching issues before you hit send. Tools like Litmus, GlockApps, and SendForensics let you test individual emails against spam filters, preview rendering across devices, and analyze content for spam triggers.

Warm-Up & Reputation Management Tools

Dedicated to building and repairing sender reputation through automated engagement. Folderly, Warmy.io, and InboxAlly use networks of real accounts to interact with your emails and train ISPs that your mail is valuable. 

Infrastructure & Compliance Monitoring

Technical tools that monitor the health of your sending infrastructure. MxToolbox, Google Postmaster Tools, and Validity Everest's compliance features track DNS records, authentication protocols, blacklist status, and adherence to Gmail or Yahoo email marketing requirements. 

All-In-One Platforms

Combine sending, warm-up, and monitoring in a single platform. Tools like Instantly and Mailtrap integrate deliverability checks directly into your campaign workflow. Both also have great API support for teams with developers.  

Enterprise Analytics Suites

Comprehensive platforms with competitive benchmarking, multi-domain monitoring, and white-label reporting. Validity Everest, MailMonitor, and enterprise tiers of Litmus offer the deepest seedlist coverage and analytics. 

What is a Seed List in Deliverability Monitoring?

If you’re looking into email deliverability monitoring tools, one of the most common terms you’ll encounter is seed lists. These are a collection of test email addresses spread across different email service providers (ESPs). 

Email deliverability monitoring tools send sample emails to their seed lists and report where your message lands (spam, promotions, or the primary inbox). So instead of testing on actual leads, you can do so safely and adjust email copy before the real campaign starts. 

Instantly.ai: Best Email Deliverability Monitoring Tool for Cold Email

Instantly.ai integrates email deliverability monitoring into the cold email workflow. Even without a paid Inbox Placement plan, you get 2 free inbox placement tests that check where your emails land (inbox, promotions, or spam).

The platform also provides accurate spam filter scores, blacklist status, authentication checks (SPF, DKIM, DMARC), and content analysis for spam triggers.

If you do get the Inbox Placement plans, you gain access to unlimited testing to track deliverability across every campaign.

What's more, the basic Growth outreach plan includes Analytics to track campaign performance (open, click, and reply rates), and Copilot to review your campaigns and suggest deliverability improvements.

Key Features:

• Tests where your emails land (inbox vs promotions vs spam)
• Spam filter scores and content insights
• Monitors 94 blacklists for your IPs and domains
• Offers AI recommendations to improve email copy
• Shows detailed deliverability per sending account
• Campaign-Level Deliverability Checks
• Built-in deliverability scoring in the sequence editor
• Preview and check deliverability scores before sending
• Advanced Infrastructure Monitoring
• Dynamic pool of rotating proxy IPs
• Continuous IP reputation monitoring
• Proactive removal of blacklisted IPs

Pricing: All users get 2 free tests to start. 

• Growth Inbox Placement: $47/month or $451/year. Unlimited one-time tests.
• Hypergrowth Inbox Placement: $97/month or $931/year. Unlimited one-time tests + Automated tests

GlockApps: The Affordable All-Rounder for SMBs and Agencies

GlockApps has remained one of the most popular email deliverability tools on the market for over a decade. It’s affordable and fits right into the email marketing stack for small businesses. The only caveat is that GlockApps mainly has seed lists in the US, which is a downside if you’re targeting UK providers like BT, Virgin, and Sky. 

GlockApps combines content analysis and inbox placement. It’s one of the best tools for sending out high-volume newsletters or nurturing emails. You get an HTML checker, spam content detection, and the ability to detect elements that trigger filters. 

Key Features:

• Spam filter scoring against Google, Barracuda, and SpamAssassin
• Full DMARC Analyzer (with 10,000 free DMARC messages/month)
• Blacklist monitoring across 50+ blocklists
• IP reputation tracking
• HTML content checking
• Gmail tab prediction (Primary vs. Promotions)
• API 2.0 access
• Notifications via Email, Slack, or Telegram
• Shareable PDF reports with white-label options for agencies

Pricing: Starts with a free plan offering 2 spam test credits per month:

• Essentials: $59/month. Includes 360 test credits and 1 user.
• Growth: $99/month. Includes 1,080 credits and 5 users, and 
• Enterprise: $129/month. Includes 1,800 credits and 20 sending accounts
• Standalone credit packs are available from $16.99 for 3 tests.

MxToolbox Delivery Center: An Infrastructure First Diagnosis

MxToolbox has been the go-to free DNS diagnostic tool for IT professionals for nearly two decades. The paid Delivery Center extends those capabilities into DMARC deployment, inbox placement analysis, and comprehensive blacklist monitoring.

However, the interface is dated. There’s also a 5-domain limit. So, it might not be ideal if you’re scaling outreach or have multiple domains. MxToolbox does make up for it with its infrastructure-first diagnostics.

It's built for IT administrators and technical teams who need robust DNS health monitoring, guided DMARC deployment to reject policy, and the industry's most extensive blacklist coverage of 100+ lists. 

Key Features:

• Monitoring against 100+ blacklists (free tier covers top 30)
• Guided DMARC deployment to reject policy
• Adaptive blacklist monitoring that auto-detects all senders
• Inbox placement analysis with MxTips improvement suggestions
• SPF flattening
• Domain impersonation protection
• BIMI record analysis

Pricing: Offers a free plan with weekly blacklist monitoring for one website:

• Delivery Center: $129/month. Includes inbox placement, DMARC guidance, up to 5 domains.
• Delivery Center Plus: $399/month. Adds adaptive blacklist monitoring, SPF flattening, impersonation protection, and dedicated expert support.
• Managed email delivery services available at custom pricing with a 30-day satisfaction guarantee.

Validity Everest: The Enterprise Deliverability Powerhouse

Validity Everest combines three major names in the deliverability space: Return Path, 250ok, and BriteVerify. Between them is over 20 years' worth of high-quality industry data. They also claim to have the largest global seed list of any deliverability tool. 

If you’re doing small campaigns, Everest can be a good choice at $20/month. However, you’re limited to 5 tests and don't get spam checks. The next paid plan is a huge jump to $525/month. For the pricetag, you get enterprise-level competitive intelligence and reputation monitoring.

Key Features:

• Inbox placement testing with competitive benchmarking
• Largest global seedlist covering 100+ webmail and hosting providers
• Real-time sender reputation monitoring across shared and dedicated IPs
• Spam trap and complaint tracking
• Built-in BriteVerify email verification
• DKIM/SPF/DMARC/BIMI authentication monitoring
• Audience engagement insights (open times, device types, dwell times)
• Integrations with Mailgun, SendGrid, Amazon SES, and Salesforce Marketing Cloud

Pricing: Follows a tiered structure with a steep pricing jump:

• Elements: $20/month. Only 5 inbox placement tests, no spam checking.
• Elements Plus: $525/month. Unlocks engagement analytics, ESP integrations, and API.
• Enterprise: Custom pricing. Industry data suggests $85,000–$106,000/year at list price.

Litmus: Premium Pre-Send Testing

Litmus was founded in 2005 and grew to serve 700,000+ marketing professionals, including 80% of the Fortune 100, as the industry's leading email testing platform. Validity acquired Litmus in April 2025, combining its pre-send optimization strengths with Validity's post-send analytics.

The biggest controversy is the August 2025 pricing restructuring. The Basic plan was gutted entirely, along with the free plan. The former Plus plan became Core at $500/month, a 151% increase. The change was also implemented without advance customer notification. 

What Litmus brings to the table is comprehensive pre-send QA. You get email previews across 100+ email clients, spam filter testing against 25+ filters, and engagement analytics showing whether emails were deleted, glanced at, or read. 

Key Features:

• Spam filter testing against 25+ filters
• Email previews across 100+ email clients and devices (including Dark Mode)
• DKIM/SPF/DMARC/BIMI authentication monitoring
• Blocklist monitoring against 60+ blocklists (Enterprise tier)
• Email Guardian for 24/7 rendering change alerts
• Deep ESP integrations with Salesforce Marketing Cloud, Oracle Eloqua, Marketo, HubSpot, Mailchimp, Klaviyo, and Adobe Campaign

Pricing: No free plan available

• Core: $500/month. Includes 5 users, 2,000 previews, 500K analytics opens
• Enterprise: Custom pricing. Industry data suggests $23,500–$36,000+/year
• Deliverability Upgrade: Requires Enterprise tier or add-on purchase (inbox placement, reputation monitoring, Everest access)

SendForensics: Deep Deliverability Analysis at Accessible Pricing

SendForensics doesn’t cut corners. All plans include all core features. The tiers only differ by volume limits (domains, users, DMARC reports). You get unlimited inbox placement tests on every plan, with fair use capped at 50 seedlist tests per domain per month. 

Despite the limitations, you still get deep deliverability analysis using machine learning. Their proprietary Email Deliverability Score (EDS) goes beyond standard spam testing to analyze individual content components. 

Key Features:

• ML-powered spam testing with proprietary Email Deliverability Score (EDS)
• Unlimited inbox placement tests on all plans (fair use: 50 tests/domain/month)
• DMARC monitoring with auto-generated starter records
• Real-time blacklist checking
• 360-degree reputation dashboard integrating Google Postmaster Tools and Microsoft SNDS data
• 24/7 infrastructure monitoring with Slack/email alerts

Pricing: Annual billing saves 20%. Non-profit discounts available.

• Brand: $49/month. Includes 2 domains, 2 users, 100K DMARC reports
• Company: $79/month. Includes 5 domains, 5 users, 1M DMARC reports
• Agency: $199/month. Includes 15 domains, 10 users
• Enterprise: Starting at $349/month. Includes 30 domains, 20 users
• Add-on domains and users cost $8–10/month each

Mailtrap: The Developer's Deliverability Platform

Mailtrap started because the team behind it accidentally sent over 200,000 test emails to customers. To prevent that from happening again, they created an internal tool that became a full email deliverability platform with over 150k monthly users, including PayPal and Adobe. 

If you’re working with a developer, Mailtrap gives tools for email testing with production sending. It's built for product companies and SaaS teams who need both a safe sandbox environment (so test emails never reach customers) and production delivery with built-in monitoring.

Key Features:

• Email API/SMTP with SDKs in 12 languages
• Dedicated IPs with automatic warm-up
• Email Sandbox that captures test emails safely
• HTML/CSS validation
• SpamAssassin scoring
• SPF/DKIM/DMARC checks
• Real-time analytics tracking delivery rates, bounce rates, and spam complaints
• ISP-level engagement breakdowns
• Free blacklist/SPF/DKIM checker tools

Pricing: Volume-based (not per-contact). Annual billing saves 20%.

• Free: 3,500 emails/month
• Basic tiers: $10/month (10K emails, 5 domains), $25/month, $50/month
• Business plans: Starting at $85/month. Includes dedicated IP, auto warm-up, 3,000 domains, 24/7 priority support
• Enterprise: Custom pricing
• Bootstrapped founders: 35% lifetime discount on Business plans

Folderly: AI-Driven Deliverability for Sales Teams

Folderly is built specifically for B2B sales teams and lead-generation agencies running cold-email campaigns at scale. It uses AI-driven warm-up with human-like engagement patterns to repair and maintain the sender's reputation. 

The main downside is that the pricing model can get expensive for small teams. But the pricing drops significantly at higher volumes (10+ mailboxes get $90 each, 100+ get $50 each). 

If you’re already sending emails in bulk, Folderly can pair your deliverability system with AI-powered monitoring and repairs. You get a real time Folderly Score, daily inbox vs. spam placement tracking, and spam trigger detection with color-coded content analysis.

Key Features:

• AI-driven email warm-up with human-like engagement patterns
• Real time Folderly Score (0-100 deliverability metric)
• Daily inbox vs. spam placement tracking
• Spam trigger detection with color-coded content analysis
• DNS configuration support (SPF, DKIM, DMARC, BIMI)
• Gmail and Outlook-specific spam reason detection
• Inbox Insights product for placement testing and IP reputation overview

Pricing: Per-mailbox model. All tiers include full feature access.

• 1-9 mailboxes: $120/mailbox/month (or $96/month annually)
• 10-24 mailboxes: $90/mailbox/month
• 25-99 mailboxes: $70/mailbox/month
• 100-499 mailboxes: $50/mailbox/month
• 500+ mailboxes: Custom pricing
• Inbox Insights: $79/month (or $799/year) for 100 tests. Only tests Gmail and Outlook.

InboxAlly: Best for Repairing Sender Reputation

InboxAlly is getting a lot of hype in the cold outreach space, even winning G2 Winter 2026 High Performer status. While it's not cost-effective for scaling deliverability across large teams, it does a great job repairing the sender reputation of previously high-performing inboxes.

Unfortunately, it’s not the best tool for smaller teams. Pricing starts at $149/month and only covers one sending account. The Jump to the next tier is at $645/month for 5 accounts. It also doesn’t have native integrations with platforms like Salesforce or SendGrid. 

What InboxAlly does best is engagement-driven reputation repair. Rather than just testing where emails land, it uses a network of real seed accounts that actively engage with your emails by opening them, clicking links, marking them as important, and moving them out of spam.

Key Features:

• Engagement-based warm-up with customizable interaction profiles
• Inbox placement testing across Gmail, Yahoo, Outlook, Hotmail, and Google Workspace
• Real-time 30-day placement tracking
• Broadcast auto-detect for campaigns
• Multiple sender profile management
• Free tools (email content tester, spam checker, blacklist lookup)
• DMARC analytics dashboard
• SPF/DKIM/DMARC auditing

Pricing: Flat monthly rates. 10-day free trial with no credit card required.

• Starter: $149/month. Includes 100 daily seed emails, 1 sender profile
• Plus: $645/month. Includes 500 daily seeds, 5 profiles
• Premium: $1,190/month. Includes 1,000 daily seeds, 10 profiles, phone support, and weekly strategy sessions
• Enterprise: Custom pricing

Key Takeaways

Businesses and agencies that want to scale email marketing need a system to ensure high email deliverability. A key part of this system is an email deliverability monitoring tool tailored to your needs. To recap, here are the tools we recommend:

• Instantly.ai: Best for scaling cold email marketing. Everything you need under one roof.
• GlockApps & MxToolbox: Affordable deliverability monitoring focusing on diagnostics.
• Everest & Litmus: Premium-priced tools best for enterprises that need global seedlists.
• SendForesenics & Mailtrap: AI-driven diagnostics and features for developers. 
• Folderly & Inbox Ally: For repairing the deliverability of previously high-performing domains.  

If you want your entire email stack in one platform, Instantly has you covered. Get domains, warm-up accounts, buy leads, automate personalization and outreach, and monitor deliverability as you scale. Try Instantly for free today.