The 12 Best Email Deliverability Tools for SaaS Teams
Choose deliverability tools for the question you need to answer: whether authentication passes, how a mailbox provider rates your sending domain, where test messages arrive, or which addresses may be invalid.
Loops is our product and appears in the sending-platform section. Diagnostic tools and sending platforms do different jobs. Compare the specific checks you need before paying for either.
Reviewed by the Loops team · product scope and pricing models rechecked September 2, 2026.
Method: we compare the job each tool does and its pricing model, not transient discounts or a universal winner. Primary sources: Google Postmaster Tools, Microsoft SNDS, GlockApps, Validity Everest, Litmus, Mailtrap, MXToolbox, EasyDMARC, dmarcian, ZeroBounce, Postmark, and Loops.
Quick comparison
Product packaging changes. Confirm the required checks, account access, limits, and price on each provider’s linked site.
Most of these tools diagnose or test email. Mailtrap also sends, and Postmark and Loops are sending platforms. Your provider operates queues and sending infrastructure. Your team still controls consent, recipients, content, and volume changes.
1. Google Postmaster Tools
Google Postmaster Tools reports Gmail reputation, spam rates, authentication, and delivery errors for qualifying senders. Data can be delayed or absent at low volume. Establish a baseline and compare a problem’s start date with changes in traffic, audience, or authentication.
2. Microsoft SNDS
Microsoft SNDS reports activity and reputation signals for sending IPs. Access requires authorization for those IPs, so a sender on a shared pool may need its email provider to investigate. Use it for Microsoft delivery problems alongside your provider’s response logs.
3. GlockApps
Sends your email to a seed list of real accounts across Gmail, Outlook, Yahoo, and others, then reports where it landed: inbox, promotions, spam, or missing. Good for spot-checking a big campaign before launch. Caveat: seed accounts behave differently from real engaged subscribers, so treat results as directional, not gospel.
4. Validity Everest
Validity offers Everest’s deliverability capabilities through Litmus. The listed features include inbox-placement insights, infrastructure monitoring, alerts, and reporting. Confirm how those capabilities are packaged before comparing the suite with individual diagnostic tools.
5. Litmus
Litmus provides email rendering previews and pre-send checks. Its site now places these capabilities within Validity Engage. Ask sales which rendering and spam-testing features are included in the proposed package, and use provider reputation data when the problem concerns delivery rather than rendering.
6. Mailtrap
Mailtrap offers a testing sandbox for inspecting messages without delivering them to customers, alongside email sending and reporting products. Check which product contains the sandbox, logs, and monitoring features you need. A staging inbox serves a different purpose from inbox-placement testing.
7. MXToolbox
MXToolbox provides SPF, DKIM, DMARC, MX, and blocklist lookups. Use manual checks to investigate a specific domain or IP. Compare paid monitoring and alert limits when you need recurring checks.
8. EasyDMARC
EasyDMARC provides authentication-record tools and aggregate DMARC reporting. Use the reports to identify legitimate sending sources before moving from monitoring to an enforcement policy. Check domain and reporting limits for your account.
9. dmarcian
dmarcian provides DMARC reporting and tools for identifying sending sources. Compare it with EasyDMARC using your own domains: check whether the reports explain failures clearly and whether the plan covers your volume and support needs.
10. ZeroBounce
Verifies addresses before you send: it estimates whether addresses are deliverable and flags risks such as disposable domains. Results do not prove consent or guarantee the absence of spam traps. Cleaning a stale list before a re-engagement campaign can reduce avoidable bounces. ZeroBounce offers a freemium plan plus usage-based credits and subscriptions. Compare current limits before choosing it over another verifier.
11. Postmark
A transactional-first service with separate message streams for transactional and broadcast mail. Postmark now supports broadcast and bulk marketing sends, but it does not provide a full audience, campaign, or lifecycle-orchestration suite. Plan to manage those capabilities in your application or another product.
12. Loops
Our product, so judge accordingly. Loops handles marketing, transactional, and lifecycle email in one platform. It provides ready-to-copy SPF, DKIM, MX, and DMARC records and verifies them after you add them at your DNS provider. Sending infrastructure, queueing, and suppression handling are managed for you. It will not give you seed-list placement tests or DMARC forensics, which is why the tools above exist. If you want the diagnostic layer and the sending layer from one vendor, that is not us.
How to choose
For Gmail delivery problems, compare Postmaster Tools with your sending provider’s logs. Use MXToolbox to check DNS or blocklist signals.
For DMARC rollout, compare EasyDMARC and dmarcian using reports from your own domains.
Seed testing such as GlockApps can show where a sample message arrived. Test accounts do not reproduce your audience’s behavior.
Evaluate Everest when you need several diagnostic functions in one suite.
Review your sending provider when logs reveal infrastructure or operational requirements it cannot meet.
Frequently asked questions
What is the best free email deliverability tool?
Do I need a deliverability tool if my ESP handles deliverability?
Why are my emails going to spam even though I pass SPF and DKIM?
How often should I clean my email list?
Related guides: our email deliverability best practices guide and why emails go to spam.