# The 11 Best Email Deliverability Tools

> The best email deliverability tool is GlockApps for its extensive seed list testing and clear reporting, followed by Validity for enterprise-scale reputation management and Mail-tester for accessible, one-off diagnostics.

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## Ranking

### #1 GlockApps · 9.2/9.4
- Best for: Marketers at SMBs and mid-market companies who need the most detailed and actionable inbox placement reports without an enterprise price tag.
- Hong Kong · founded 2011 · $$ ($79 to $399/mo)
- GlockApps is the best email deliverability tool for its superior inbox placement testing, offering one of the most diverse seed lists covering international ISPs and clear, actionable reporting that pinpoints specific filtering issues.
- Pro: Its bounce analytics provide specific, non-generic reasons for delivery failures, which is a significant step up from standard ESP reporting.
- Con: The user interface, while functional, feels dated compared to newer platforms and can require multiple clicks to find specific data points.
- Risk signals (none, checked 2026-06-15): No material public risk signals as of 2026-06-15.

### #2 Validity · 9/9.4
- Best for: Large enterprises and high-volume senders who require the most powerful suite for sender reputation, certification, and blocklist remediation.
- Boston, USA · founded 2018 · $$$$ (Custom pricing, est. >$1500/mo)
- Validity ranks second as the undisputed leader for enterprise-grade deliverability, combining the power of Return Path, 250ok, and BriteVerify into a single platform that offers unparalleled data and sender certification programs.
- Pro: Their Everest platform provides access to the industry's largest data network, offering predictive insights into how mailbox providers view your mail.
- Con: The platform is prohibitively expensive for most small to mid-sized businesses, and its complexity requires a dedicated deliverability expert to operate effectively.
- Risk signals (none, checked 2026-06-15): No material public risk signals as of 2026-06-15.

### #3 Mail-tester · 8.8/9.4
- Best for: Marketers, developers, and small businesses needing a quick, simple, and affordable way to check the 'spamminess' of an email before sending.
- London, UK · founded 2014 · $ (Pay-as-you-go or $50/mo)
- Mail-tester earns its high rank for being the most accessible and straightforward diagnostic tool on the market, providing an instant 1-10 score by checking SPF/DKIM records, blocklists, and message formatting from a single test email.
- Pro: The simplicity of sending one email to a unique address and getting an immediate, detailed report is unmatched for quick troubleshooting.
- Con: It is not a continuous monitoring platform; it only provides a point-in-time snapshot and lacks the seed list depth for true inbox placement prediction.
- Risk signals (none, checked 2026-06-15): No material public risk signals as of 2026-06-15.

### #4 Kickbox · 8.5/9.4
- Best for: Teams that need to combine best-in-class email verification with a solid suite of deliverability monitoring tools.
- Dallas, USA · founded 2014 · $$ ($5 to $1000+ pay-as-you-go)
- Kickbox stands out by integrating its top-tier email verification service directly with a capable set of deliverability tools, making it an ideal all-in-one platform for ensuring both list quality and inbox placement.
- Pro: The platform's 99.5% verification accuracy guarantee is a market leader, directly improving deliverability outcomes before an email is even sent.
- Con: Its inbox placement seed list is less extensive than GlockApps, particularly for non-US mailbox providers, potentially giving a less complete picture for global senders.
- Risk signals (none, checked 2026-06-15): No material public risk signals as of 2026-06-15.

### #5 Folderly · 8.3/9.4
- Best for: Sales and marketing teams focused on cold outreach who need to fix existing deliverability problems and avoid spam traps.
- Wilmington, USA · founded 2019 · $$$ ($200 to $2000/mo)
- Folderly secures its position by focusing specifically on solving deliverability issues for cold outreach, offering a unique blend of software diagnostics and managed services for spam trap removal and domain health restoration.
- Pro: Its ability to detect and report on placement within specific Google Workspace and Outlook 365 spam filters is highly valuable for B2B senders.
- Con: The platform is more expensive than general-purpose tools, and its feature set is narrowly focused on outreach use cases, making it less suitable for bulk marketing.
- Risk signals (none, checked 2026-06-15): No material public risk signals as of 2026-06-15.

### #6 Email on Acid by Sinch · 8.1/9.4
- Best for: Email teams who want to combine pre-send content and rendering checks with solid deliverability monitoring in a single workflow.
- Denver, USA · founded 2009 · $$ ($99 to $599/mo)
- Email on Acid is a strong contender because it integrates deliverability testing directly into its market-leading email rendering and validation workflow, allowing teams to catch both code and reputation issues before hitting send.
- Pro: The Campaign Precheck feature, which combines accessibility, image, and link checks with deliverability tests, saves significant time for production teams.
- Con: Its deliverability features, while good, are less in-depth than dedicated platforms like GlockApps; for example, its seed list is smaller.
- Risk signals (none, checked 2026-06-15): No material public risk signals as of 2026-06-15.

### #7 Litmus · 7.9/9.4
- Best for: Marketing organizations that prioritize email design and analytics and want an integrated tool for deliverability checks.
- Cambridge, USA · founded 2005 · $$$ ($199 to $499/mo)
- Litmus provides solid deliverability features, including spam testing and blocklist monitoring, fully integrated into its industry-standard platform for email building, testing, and analytics, making it a great choice for teams seeking efficiency.
- Pro: The integration of spam testing within the Litmus Test checklist ensures deliverability is not an afterthought during the email creation process.
- Con: As with Email on Acid, the deliverability toolset is a feature of a larger platform rather than a specialized, best-in-class solution, lacking the depth of top-ranked competitors.
- Risk signals (none, checked 2026-06-15): No material public risk signals as of 2026-06-15.

### #8 SendForensics · 7.7/9.4
- Best for: Technically-minded marketers and deliverability consultants who need deep, forensic analysis of their email infrastructure and content.
- London, UK · founded 2012 · $$ (From £49/mo)
- SendForensics carves out a niche with its highly technical, in-depth analysis of email headers, server configurations, and content, providing a level of forensic detail that other platforms do not match.
- Pro: Its pre-emptive deliverability modeling provides a unique forecast of potential issues before a single email is sent to your list.
- Con: The platform's output is dense and highly technical, making it less accessible for general marketers without a background in email protocols.
- Risk signals (none, checked 2026-06-15): No material public risk signals as of 2026-06-15.

### #9 ZeroBounce · 7.5/9.4
- Best for: Marketers who primarily need an email verification service but want to add on basic deliverability tools like inbox testing and blocklist monitoring.
- Santa Barbara, USA · founded 2015 · $ (Pay-as-you-go or $15/mo+)
- ZeroBounce makes the list as a top-tier email validation service that has successfully expanded its offering to include a useful, though basic, set of deliverability tools available as an add-on to its core product.
- Pro: The pay-as-you-go pricing for all its services, including the deliverability toolkit, provides great flexibility for teams with fluctuating needs.
- Con: The deliverability tools are not as mature or feature-rich as those from specialized providers, serving more as a convenient add-on than a main reason to choose the platform.
- Risk signals (none, checked 2026-06-15): No material public risk signals as of 2026-06-15.

### #10 Postmastery · 7.2/9.4
- Best for: ESPs, marketing clouds, and other high-volume senders needing expert consultancy combined with powerful, self-hosted software.
- Amsterdam, Netherlands · founded 2010 · $$$$ (Custom pricing)
- Postmastery offers a unique combination of deliverability software and deep consulting expertise, making it a valuable partner for organizations managing complex sending infrastructures like PowerMTA.
- Pro: Their specific expertise in managing and optimizing on-premise mail transfer agents (MTAs) is a rare and valuable skill set.
- Con: This is not a self-service SaaS platform for the average marketer; it is a high-touch, high-cost service for a technical audience.
- Risk signals (none, checked 2026-06-15): No material public risk signals as of 2026-06-15.

### #11 [WILDCARD] Warmup Inbox · 7/9.4
- Best for: New businesses or sales teams setting up new sending domains that need to build a positive sender reputation from scratch.
- Wilmington, USA · founded 2020 · $ ($19 to $199/mo)
- Warmup Inbox is the wildcard because it tackles deliverability proactively rather than diagnostically, using a network of inboxes to automatically generate positive engagement for your new domain, which builds reputation with ISPs over time.
- Pro: The platform automates a tedious but critical process, ramping up sending volume and generating replies to signal to Gmail and Outlook that you are a legitimate sender.
- Con: This is a single-purpose tool for a specific phase of an email program; it does not replace the need for ongoing monitoring and diagnostic tools once a domain is mature.
- Risk signals (none, checked 2026-06-15): No material public risk signals as of 2026-06-15.

## FAQ

**What is the difference between email deliverability and delivery?**

Email delivery means the receiving server accepted the email, but it does not specify where it was placed. Email deliverability refers to where the email actually landed, specifically whether it reached the inbox versus the spam folder, a promotions tab, or was blocked post-acceptance.

**How can I check my email deliverability for free?**

You can perform basic free checks using tools like Mail-tester, which often provide one free test, or by setting up free DMARC monitoring with a service like Postmark's DMARC tool. Additionally, sending test emails to your own accounts at Gmail, Outlook, and Yahoo can provide a small, manual sample of your inbox placement.

**What is a good email deliverability rate?**

A good inbox placement rate is generally considered to be 95% or higher. However, this can vary by industry and list quality. Rates below 85% often indicate a significant reputation or content issue that needs immediate attention. Consistently monitoring this rate is more important than a single number.

**How do DMARC, DKIM, and SPF affect deliverability?**

These three authentication protocols prove to receiving mail servers that you are a legitimate sender. SPF (Sender Policy Framework) lists authorized sending IPs. DKIM (DomainKeys Identified Mail) adds a digital signature to verify content integrity. DMARC (Domain-based Message Authentication, Reporting, and Conformance) tells receivers what to do with emails that fail SPF or DKIM checks, preventing spoofing and improving your domain's reputation.