- Deliverability tools by job: testing, QA and warm-up
- Ten email deliverability tools
- Two email QA names now live inside bigger sending platforms
- Placement testing, spam checks, QA or warm-up
- A deliverability routine before every big send
- My plain advice on email deliverability tools
- Frequently asked questions
Email deliverability tools show whether your emails reach the inbox or the spam folder, and help you fix the reasons why. They split into placement testing across inbox providers, spam and authentication checkers, email QA before send, and warm-up and infrastructure for cold outreach. Ten tools follow in no particular order.
Sending an email and having it delivered aren't the same thing. Your platform may report it as delivered while Gmail quietly files it in spam or Promotions. Deliverability tools send test copies to seed inboxes, check your SPF, DKIM and DMARC records, and flag content or reputation problems before your audience ever sees them.
This list puts placement testing and QA first, with warm-up tools for cold outreach after that. The ten tools below are listed alphabetically and in no particular order, and every description comes from each vendor's own website, read as of Oct 2026. For the full list of things to check, my email deliverability checklist is a good companion.
Deliverability tools by job: testing, QA and warm-up
I checked the free plan column on each vendor's own website, as of Oct 2026. Yes means the page names a free plan, a free version or an open source edition. Trial only means it names a time-limited free trial. Not stated means the page I read named neither, so check the vendor's own site before you sign up.
| Tool | Type | Good for | Free plan |
|---|---|---|---|
| Email on Acid | Email QA (now Mailgun Inspect) | Checking HTML, links and images before send | Trial only |
| Folderly | Deliverability tools for B2B | Placement tests, DNS checks and alerts | Not stated |
| GlockApps | Inbox placement testing | Seeing where a campaign lands before send | Not stated |
| InboxKit | Email infrastructure for outreach | Mailboxes with blacklist and DNS monitoring | Not stated |
| Litmus | Email testing (now Validity Engage) | Previews, testing and live monitoring | Not stated |
| MailGenius | Spam checker | Quick spam checks before a send | Yes |
| MailReach | Warm-up and spam testing | Spam tests plus inbox warm-up | Not stated |
| Validity Everest | Inbox placement and deliverability | AI-powered placement and monitoring | Not stated |
| Warmbox | Inbox warm-up | Warming cold email inboxes | Not stated |
| Warmup Inbox | Email warm-up tool | Sender reputation and IP warm-up | Trial only |
Ten email deliverability tools
Email on Acid
Best for: Email teams checking every corner of their HTML, links, images and accessibility before send, now inside Mailgun Inspect.
Folderly
Best for: B2B teams that want to test inbox placement, sending IPs and DNS, then monitor placement with alerts and AI help drafting campaigns.
GlockApps
Best for: Testing where a campaign lands across Gmail, Outlook, Yahoo and more before you send, plus SPF, DKIM, DMARC and blocklist checks.
InboxKit
Best for: Outreach teams setting up Google, Microsoft 365 and Azure mailboxes with blacklist and DNS monitoring and unlimited placement tests.
Litmus
Best for: Marketing teams building, previewing and testing emails before they reach inboxes, with 24/7 live monitoring alerts.
MailGenius
Best for: Quick spam checks before a send, testing your email against SPF, DKIM, DMARC, BIMI and blacklist checks in one report.
MailReach
Best for: Cold emailers who want a free spam test plus warm-up for Google, Outlook, SendGrid, Mailgun, Amazon SES and SMTP inboxes.
Validity Everest
Best for: Senders wanting AI-powered inbox placement and live email monitoring, with an MCP connector that brings inbox data into AI tools.
Warmbox
Best for: Warming up cold email inboxes across Gmail, Outlook, Yahoo, iCloud, Zoho and SMTP before you start outreach.
Warmup Inbox
Best for: Sales teams building sender reputation automatically, with ESP and dedicated IP warm-up and a free 60-second placement test.
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Two email QA names now live inside bigger sending platforms
Here's what I found on the vendor pages. The Litmus home page now says it's part of Validity Engage, and the Email on Acid page says it's now part of a next-generation email QA suite called Mailgun Inspect. Two long-standing independent email testing names are now features inside larger sending and deliverability platforms.
That's useful if you already use the parent company, and worth checking if you don't. Ask whether the tool still works with any sending platform or is being pulled towards its owner's own.
Placement testing, spam checks, QA or warm-up
- Placement testing. Sends your email to seed inboxes at Gmail, Outlook, Yahoo and others, then shows inbox, spam or missing for each.
- Spam and authentication checks. Scores your content and checks SPF, DKIM, DMARC, BIMI and blocklists in one report.
- Email QA. Previews how an email renders across devices and inboxes and checks links, images and accessibility before send.
- Warm-up and infrastructure. For cold outreach: sets up mailboxes and builds sender reputation gradually before you send at scale.
A deliverability routine before every big send
- Check SPF, DKIM and DMARC are set up and passing on your sending domain.
- Run a placement test to a seed list and note where each provider files the email.
- Run a spam check on the content, links and images.
- Preview the email on the main devices and inboxes your audience uses.
- After sending, watch bounces and complaints, and pause if either jumps.
If an email still lands in spam after all that, the cause is usually reputation or list quality. My explainer on why emails get marked as spam covers the usual culprits.
Do you make an email deliverability tool? Tool makers can ask to be considered for a featured place on this list.
My plain advice on email deliverability tools
Start with a placement test and an authentication check before you buy anything bigger. Most deliverability problems show up there, and fixing a DNS record takes minutes. Add email QA if your emails are designed and coded, and warm-up only if you're sending cold outreach from new mailboxes.
And test before every big send, not after a bad one. A few minutes of testing beats a week of wondering why clicks dropped.
Want your tool on this list? Featured spots and reviews here are paid partnerships. Here's how to partner with me.
Frequently asked questions
What is email deliverability?
It's whether your emails reach the inbox rather than the spam folder or nowhere at all. It depends on authentication, sender reputation, content and list quality.
What is an inbox placement test?
It sends your email to a set of test inboxes at providers such as Gmail, Outlook and Yahoo, then reports where each copy landed.
Do I need email warm-up?
Only for new mailboxes or domains used for cold outreach. Warm-up builds sender reputation gradually before you send at volume.
What are SPF, DKIM and DMARC?
They're DNS records that prove your emails come from you. Inbox providers check them, and missing or failing records push emails towards spam.
Is there a free email spam checker?
Yes. One tool on this list names a free spam checker in its page title, shown in the free plan column, and several others offer free single tests.
