Free Email Deliverability Test: 9 Free Tools for 2026

By The Skitrate Machine 2026-08-28 19 min read

The fastest free email deliverability test takes under 60 seconds: send one message to Mail-Tester, refresh the page, and read a score out of 10. That number tells you whether your content and authentication look clean, but it does not confirm inbox placement. A complete free email deliverability test in 2026 stacks three free layers: a content and authentication check (Mail-Tester or MailGenius), a Gmail reputation view (Google Postmaster Tools v2), and a multi-provider seed placement test (GlockApps, GMass, or EasyDMARC). This guide runs all three, reads every output line, and fixes the SPF, DKIM, DMARC, and complaint-rate problems that keep B2B email out of the inbox.

What a free email deliverability test actually measures

A free email deliverability test is not a mailbox audit. It is a seed-list test. The tool controls a set of real inboxes at Gmail, Outlook, Yahoo, and other providers, you send your message to those addresses, and the tool reports where each copy landed and why. That is an estimate of inbox placement, not a guarantee for your real recipients. Understanding that distinction is the difference between reading the results correctly and chasing a vanity score.

Free tools measure three separate things, and most people conflate them. First, content scoring. Tools like Mail-Tester and MailGenius run your message through SpamAssassin, a rules engine that assigns points for spam-associated patterns: image-heavy layouts with no text part, spammy phrases, URL shorteners, mismatched link domains, and broken HTML. Mail-Tester starts you at 10 out of 10 and subtracts points for each rule your message trips.

Second, authentication validation. Every serious tool checks whether SPF, DKIM, and DMARC pass and align with your From domain. This is the layer mailbox providers now enforce as a hard requirement, not a nice-to-have. Third, inbox placement. This is the seed-list part: the tool sends to monitored addresses and records inbox versus spam versus promotions, per provider, sometimes with a time-to-deliver metric.

The word free almost always means the seed-list or content-scoring layer, because those are cheap to run. True mailbox-panel monitoring at scale sits behind paid tiers. For a pre-send check, the free layers catch the majority of problems: a missing DKIM signature, an SPF record that softfails, a DMARC policy that does not exist, a sending IP on a blacklist, or a template that SpamAssassin hates. What free tests cannot see is your engagement history and complaint rate at each provider. Gmail decides placement partly on how your past recipients behaved, and no external seed test can observe that. This is why a clean 10 out of 10 can still land in spam. Treat the free test as triage that finds fixable technical faults, then confirm reputation separately.

Why free deliverability testing became non-optional in 2026

For a decade, deliverability testing was optional hygiene. Two waves of mailbox-provider enforcement changed that. The first hit on February 1, 2024, when Gmail and Yahoo turned their sender best practices into hard requirements for any domain sending 5,000 or more messages per day to their users. The second hit on May 5, 2025, when Microsoft extended similar authentication requirements to its consumer Outlook.com, Hotmail, Live, and MSN domains. Both changes moved authentication and complaint rate from advice to enforcement, and both reject or block non-compliant mail rather than quietly filtering it.

According to Google's email sender guidelines, bulk senders must authenticate with SPF and DKIM, publish a DMARC record, keep spam complaints low, and support one-click unsubscribe. As AWS documented in its overview of the bulk-sender changes, the thresholds are specific and public. Here is the enforcement timeline B2B senders are testing against in 2026.

Since February 1, 2024, Gmail and Yahoo have automatically blocked bulk senders (5,000 or more messages per day to their users) whose spam complaint rate reaches 0.30% or higher, and both providers tell senders to stay under 0.10%. Source: Google email sender guidelines, 2024.

Two numbers matter most. The 0.10% target is roughly one complaint per 1,000 delivered messages, and the 0.30% ceiling is three per 1,000. Cross the ceiling and placement degrades or mail is blocked outright. Email still returns a reported $36 for every $1 spent according to Litmus, which is exactly why a single blocked domain is expensive: the channel with the best return is also the one a bad send can silently switch off. Testing before you send is the cheapest insurance available, and the rest of this guide is a repeatable free workflow that verifies you are inside every one of these lines before a campaign leaves the building.

Prerequisites: accounts, DNS access, and tool versions

Before you run a single test, assemble access. A free email deliverability test is only accurate if you send from the exact infrastructure your real campaigns use. Testing from a personal Gmail account or a warmed inbox that does not match your production sending domain produces results you cannot act on. Gather the following.

• A sending domain you control, with a subdomain dedicated to marketing mail if possible, for example news.example.com, so reputation is isolated from transactional and corporate mail.
• DNS management access at your registrar or DNS host (Cloudflare, Route 53, GoDaddy) to publish TXT records for SPF, DKIM, and DMARC. This is squarely technical SEO and DNS work, so loop in whoever owns the zone.
• Your ESP or sending platform with DKIM signing available, for example a current build of your ESP (SendGrid, Mailchimp, Klaviyo, Customer.io) or a self-hosted Postfix 3.x with OpenDKIM.
• A command line with dig (bind-tools 9.x) or nslookup to read DNS records, plus access to view raw message headers in your mailbox.
• A Google account for Google Postmaster Tools v2, the free Gmail reputation dashboard.
• Browser access to the free testers: Mail-Tester, MailGenius, GlockApps (free personal plan), the EasyDMARC deliverability test, the GMass inbox tester, and the MXToolbox SuperTool.
• A representative campaign creative, the real HTML you plan to send, not a one-line test, because SpamAssassin scores the actual content.

Version detail matters in one place: use Google Postmaster Tools v2, not cached screenshots of v1. Google retired v1 in October 2025, and the old High, Medium, Low, and Bad reputation labels no longer exist. If a tutorial still shows colored reputation bars, it predates the current dashboard and will send you looking for a screen that is gone. Confirm your dig binary is present before you start, because every authentication check in this guide reads DNS directly rather than trusting an ESP status page that can lag reality by hours.

9 free email deliverability test tools compared in 2026

The free market splits into three job types. Content and authentication scorers grade one message. Seed-list placement testers send to monitored inboxes across many providers. Reputation dashboards report how a real mailbox provider already sees you. The strongest free workflow uses one of each. The table below compares the nine tools worth keeping in a 2026 toolkit, with the free-tier limit that actually matters, because most of these products upsell hard once you cross a low ceiling.

Read the free limits literally. Mail-Tester gives you three checks per 24-hour window. GlockApps and EasyDMARC hand you a small number of free tests, then meter you. Google Postmaster Tools is genuinely free forever but only sees Gmail. MailGenius and the GMass inbox tester are the closest to unlimited free, which is why they anchor a zero-budget workflow.

No tool on that list is a full substitute for the others. Mail-Tester and MailGenius tell you whether the message is clean. GlockApps, EasyDMARC, GMass, and EmailWarmup tell you where it lands. Postmaster Tools tells you what Gmail already thinks of your domain. MXToolbox tells you whether your DNS and IP are the problem. A B2B team on a zero budget can build a legitimate free email deliverability test by chaining MailGenius or Mail-Tester for content, the GMass tester for Gmail placement, EmailWarmup for other providers, and Postmaster Tools for reputation. If you send at real volume and want AI automation around recurring tests and alerting, the paid tiers of GlockApps or Validity are where free workflows graduate, but you should exhaust the free stack first.

Step-by-step: the 12-step free deliverability test workflow

This is the core runbook. Follow the twelve steps in order. Each one names the exact screen you are on and the output you should see, so you can tell a pass from a fail without guessing. Budget 30 to 45 minutes the first time, then 10 minutes for repeat runs. Nothing here costs money.

1. Confirm you control the sending domain and its DNS. Run a lookup from your terminal. Output: your existing records print, for example v=spf1 include:_spf.google.com -all. If nothing prints, you have no SPF yet, which is finding number one.
2. Open Mail-Tester and copy the unique test address. Screenshot: a green box in the center of the page shows an address like [email protected]. Copy it and do not refresh yet.
3. Send your real campaign creative to that address from your production ESP. Screenshot: your ESP compose window with the full HTML email, your normal From name, subject line, and footer. Send a single copy to the Mail-Tester address.
4. Return to Mail-Tester and click Then check your score. Output: a large score such as 7/10, with a breakdown panel below it. Anything under 8 out of 10 has fixable faults.
5. Read the deduction list line by line. Output example: -1.5 You do not have a valid SPF record; -1 Your message contains HTML but no text version; -0.5 Your message contains a URL listed in a blacklist. Each line is a task.
6. Cross-check DNS and blacklists in the MXToolbox SuperTool. Screenshot: green check rows for SPF, DKIM, and DMARC, plus a blacklist panel scanning 100+ RBLs. A red listing on your sending IP explains placement problems no content fix will solve.
7. Sign in to Google Postmaster Tools v2 and add your domain. Output: Google gives you a TXT verification string such as google-site-verification=Ab12Cd34. Publish it in DNS, then click Verify.
8. Wait 24 to 72 hours for Gmail data, then open Compliance Status. Screenshot: rows for Authentication, Alignment, Unsubscribe, and Spam rate, each marked Compliant, Needs work, or No data found. Target all green.
9. Open the Spam rate chart. Screenshot: a line graph with a red reference line at 0.30% and a caution zone at 0.10%. Your reported rate must sit below 0.10%. A spike above 0.30% predicts blocking.
10. Run a multi-provider seed test in GlockApps or the GMass tester. Output: a placement grid, for example Gmail Inbox 100%, Outlook Inbox 80% and Spam 20%, Yahoo Inbox 100%. This is the closest free proxy for real inbox placement across providers.
11. Inspect the raw headers of one delivered seed message. Output: an Authentication-Results line reading spf=pass dkim=pass dmarc=pass. Any fail here is your top priority, because providers now block on it.
12. Fix, re-publish DNS, and re-test until the score, placement, and Compliance Status all pass. Output: Mail-Tester at 9 or 10 out of 10, GlockApps placement green, Postmaster Compliance all Compliant. Record the numbers and the date, then set a re-test before every major send.

How to read your SPF, DKIM, and DMARC results

Authentication is the layer providers enforce, so read it first. Three DNS-based mechanisms work together. SPF lists which servers may send for your domain. DKIM cryptographically signs each message so the receiver can verify it was not altered and came from you. DMARC ties the two together, tells receivers what to do when a message fails, and requests reports. Pull all three from the command line.

dig TXT example.com +short
dig TXT selector1._domainkey.example.com +short
dig TXT _dmarc.example.com +short

Read the results like this. A valid SPF record starts with v=spf1, lists your senders through include or ip4 mechanisms, and ends in -all (hard fail) or ~all (soft fail). More than 10 DNS lookups inside the record breaks SPF with a permerror, a common silent failure. A DKIM lookup at your selector should return a v=DKIM1 record with a public key in the p= tag. If it returns nothing, your ESP is either not signing or you published the key at the wrong selector. A DMARC record lives at _dmarc.yourdomain and starts with v=DMARC1 followed by a policy.

The definitive check is not the DNS record, it is what the receiver reports. Open the raw headers of a message you sent to yourself or to a seed inbox and find the Authentication-Results header.

Authentication-Results: mx.google.com;
  spf=pass (google.com: domain of [email protected] designates 198.51.100.10 as permitted sender) [email protected];
  dkim=pass [email protected] header.s=selector1;
  dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=example.com

You want three passes: spf=pass, dkim=pass, and dmarc=pass. DMARC needs more than a pass on SPF or DKIM alone, it needs alignment, meaning the domain that passed must match your visible From domain. A message can show spf=pass and still fail DMARC if the passing domain belongs to your ESP rather than you. That is the single most common authentication trap in B2B email, and it is invisible unless you read the header.

Reading a Mail-Tester score: what each deduction means

Mail-Tester presents a single number out of 10, but the number is meaningless until you read the itemized deductions. The tool starts every message at a perfect 10 and subtracts SpamAssassin points, authentication penalties, and infrastructure penalties. Here are the deductions you will see most often in 2026, with what each one means and roughly how many points it costs.

• Missing or failing SPF (about 1 to 2.5 points). No v=spf1 record, or the sending IP is not authorized. Publish or correct the SPF record.
• Missing DKIM signature (about 1 to 2.5 points). Your ESP is not signing, or the selector is wrong. Enable DKIM in the ESP and publish the key.
• No DMARC record (about 1 point). No _dmarc entry exists. Publish at least v=DMARC1; p=none.
• HTML with no plain-text part (about 1 point). You sent HTML only. Send multipart/alternative with a text version.
• Spammy phrases and formatting (variable). All-caps subjects, excessive exclamation marks, oversized red fonts, and known trigger phrases each add SpamAssassin points.
• Blacklisted sending IP or domain (about 0.5 to 3 points). Your IP or a linked URL appears on an RBL. Delist and investigate the neighbor if you are on a shared IP.
• URL shorteners and mismatched links (variable). Shortened links and link text whose visible domain differs from the href. Use full branded links.
• Missing List-Unsubscribe header (about 0.5 point). No one-click unsubscribe. Add the RFC 8058 headers.
• Broken or unbalanced HTML (variable). Unclosed tags and an oversized image-to-text ratio. Clean the template.

Fix the authentication and infrastructure deductions first, because they carry the most weight and also satisfy provider enforcement. Content deductions matter, but a 10 out of 10 achieved by gutting your creative is not worth losing conversions, which is a conversion rate optimization tradeoff, not just a deliverability one. The goal is a clean score with the message you actually want to send, not a sterile one nobody clicks.

How to read Google Postmaster Tools v2 Compliance Status

Mail-Tester and seed tests estimate. Google Postmaster Tools v2 reports what Gmail actually observes about your domain, which makes it the closest thing to ground truth in a free stack. Two things changed in the v2 era, and both matter for how you read it.

First, the reputation bars are gone. Google retired v1 in October 2025 and removed the High, Medium, Low, and Bad domain and IP reputation labels. In their place is a Compliance Status dashboard that grades each bulk-sender requirement as Compliant, Needs work, or No data found. As Practical Ecommerce reported, the shift moves the tool from a reputation view to a rule-compliance view: the question is no longer whether your reputation is High, it is whether you meet the requirements. Second, in early June 2026 Google added a Deliverability Analysis section to the Compliance Status page. Instead of leaving you to interpret a spam-rate graph, it states a plain-English verdict, adds a short description, and recommends an action.

550 5.7.515 Access denied, sending domain [your-domain] does not meet the required authentication level. Microsoft began returning this rejection to high-volume senders to its consumer Outlook, Hotmail, Live, and MSN domains on May 5, 2025.

That block, which Microsoft announced ahead of enforcement, is a hard rejection, not a spam-folder placement. Read the Gmail dashboard in this order. Confirm Authentication is Compliant, which means SPF and DKIM pass at the volume Gmail sees. Confirm Alignment is Compliant, meaning your From domain aligns with the authenticated domain. Confirm Unsubscribe is Compliant, meaning your one-click header is present and valid. Then watch the Spam rate, the one metric with a hard number: keep the user-reported rate below 0.10%. A No data found state usually means you are below the volume Gmail needs to report, not that you passed. If Postmaster shows Needs work on any row, fix that row before you send another campaign, because Gmail is telling you in advance which rule you are about to break.

Fixing authentication failures step by step

When a free deliverability test flags SPF, DKIM, or DMARC, the fix is a DNS change and a wait for propagation. Work in this order, because DMARC depends on SPF and DKIM being correct first. Fix SPF. Publish exactly one SPF record. Multiple v=spf1 records for the same domain is itself a failure. Include every service that sends for you, keep the total DNS lookups at 10 or fewer, and end with -all once you are confident the list is complete.

; Correct SPF: one record, ends in -all, under 10 DNS lookups
example.com.  IN  TXT  v=spf1 include:_spf.google.com include:sendgrid.net -all

Fix DKIM. Turn on DKIM signing in your ESP, which generates a key pair and gives you a selector and a public key. Publish the public key as a TXT record at selector._domainkey.yourdomain. Use a 2048-bit key where the ESP supports it.

; DKIM public key published at selector1._domainkey
selector1._domainkey.example.com.  IN  TXT  v=DKIM1; k=rsa; p=MIGfMA0GCSq...QAB

Fix DMARC. Publish a DMARC record at _dmarc.yourdomain. Start at p=none so you monitor without blocking your own mail, point rua at a mailbox that collects aggregate reports, and set strict alignment only after reports confirm your legitimate mail passes.

; Start at p=none, collect reports, then ramp to quarantine and reject
_dmarc.example.com.  IN  TXT  v=DMARC1; p=none; rua=mailto:[email protected]; ruf=mailto:[email protected]; pct=100; adkim=s; aspf=s; fo=1

After publishing, allow up to 48 hours for DNS to propagate, then re-run the dig checks and re-send to Mail-Tester. The Authentication-Results header on the received message is the proof: spf=pass, dkim=pass, and dmarc=pass with alignment. Do not move DMARC to p=reject until your aggregate reports show that all of your legitimate sending sources, including your ESP, your CRM, and any third-party tools that send on your behalf, pass alignment. Jumping to p=reject early is the fastest way to block your own invoices and password resets, and it is the single most common self-inflicted deliverability outage in B2B.

Setting up one-click unsubscribe under RFC 8058

One-click unsubscribe stopped being optional for promotional bulk mail on June 1, 2024. Gmail, Yahoo, and Microsoft all expect the header, and free deliverability tests now deduct points when it is missing. The mechanism is defined in RFC 8058 and works alongside the older List-Unsubscribe header from RFC 2369. You need two headers on every promotional message. The first advertises an unsubscribe URL and mailto. The second signals that the URL supports a single POST request with no further confirmation, which is what makes it one-click.

List-Unsubscribe: <
;, <mailto:[email protected]?subject=unsub-abc123>
List-Unsubscribe-Post: List-Unsubscribe=One-Click

Three rules make or break it. First, the unsubscribe endpoint must accept an HTTP POST with the body List-Unsubscribe=One-Click and must not require the user to log in or click a confirmation. Second, the header must be present on the message as sent, so verify it in the raw headers of a delivered test, not just in your ESP settings. Third, honor the request fast. Providers expect the address to stop receiving mail within a short window, and a slow or broken unsubscribe drives the complaint rate up, which is the metric that gets you blocked.

Most modern ESPs add these headers automatically once you enable one-click unsubscribe in the campaign settings. If you send through a self-hosted stack, you inject the headers yourself and stand up an endpoint that processes the POST. Either way, the free test tells you whether it is actually present on the wire, which is the only thing that counts. A common failure is an ESP that shows the toggle as on while a custom sending route strips the header downstream, so always confirm from a received copy.

Multi-provider seed testing beyond Gmail

Google Postmaster Tools is the best free reputation view you have, and it only covers Gmail. Your B2B list is not only Gmail. It is Outlook.com and Microsoft 365, Yahoo and AOL, Apple iCloud, and a long tail of corporate mail systems that each filter differently. To see those, you need a seed-list placement test, because no free reputation dashboard exists for them.

Seed testing remains necessary because Google Postmaster Tools only covers Gmail, which makes cross-provider test tools more useful for Outlook, Yahoo, Apple Mail, regional ISPs, and corporate mail systems. Source: Sender email deliverability guide, 2025.

As Sender's deliverability guide notes, a seed test sends your campaign to a set of monitored inboxes and reports placement per provider. The free options differ in coverage and honesty about their limits.

• GlockApps sends to 70 or more seed addresses across Gmail, Outlook, Yahoo, AOL, and corporate servers, and returns a per-provider Inbox, Spam, or Tab breakdown. The free personal plan includes a small number of tests before metering.
• EasyDMARC's deliverability test uses real inboxes, reports Inbox, Spam, or Promotions with time-to-receive, and ties results back to your DNS and authentication records. The free tier keeps 14 days of history.
• GMass inbox tester publishes a fixed set of roughly 15 to 20 Gmail seed addresses, some wired to Barracuda, Mimecast, and Sophos filters, and is free and effectively unlimited for Gmail-first cold outreach.
• EmailWarmup's free test spans Gmail, Outlook, Yahoo, and 50 or more providers for a broad snapshot when you want coverage over depth.
• Mailtrap and MailReach add spam-score and placement checks that fit neatly into a staging pipeline before production sends.

The practical move is to run one Gmail-first test and one broad-provider test on every important campaign. If Outlook shows spam while Gmail shows inbox, your problem is almost always Microsoft-specific authentication or a SmartScreen content trigger, not a universal fault, and you fix it against Microsoft's rules rather than Google's.

5 common pitfalls in free deliverability testing

Most bad deliverability decisions come from misreading a free test, not from the test being wrong. These are the pitfalls that waste the most time, and the fix for each.

• Pitfall: testing with a blank or one-line email. SpamAssassin scores your real creative, not a stub, so a stub score is fiction. Fix: always send the exact HTML campaign you plan to broadcast.
• Pitfall: sending the test from the wrong infrastructure. A message from your personal inbox or an unrelated domain tells you nothing about your production sending domain. Fix: send from the identical ESP, IP, and From domain the campaign will use.
• Pitfall: chasing a perfect 10 and assuming inbox placement. A 10 out of 10 means clean content and authentication, not reputation. Messages have scored 9 or 10 and still gone to spam. Fix: pair the score with Postmaster Tools and a live seed test.
• Pitfall: reusing the same seed inboxes for months. Seed addresses that never open, click, or reply get trained by providers and stop reflecting real placement. Fix: rotate seeds, and prefer panels that interact with mail.
• Pitfall: treating Gmail results as universal. Postmaster is Gmail only, and Outlook filters differently. Fix: always add an Outlook, Yahoo, and Apple seed test.
• Pitfall: jumping DMARC to p=reject too early. You block your own legitimate mail from sources you forgot about. Fix: start at p=none, read aggregate reports, then ramp to quarantine and reject.
• Pitfall: ignoring the sending IP's blacklist status. No content edit fixes an RBL listing. Fix: check MXToolbox, request delisting, and if you are on a shared IP, evaluate a dedicated IP or a cleaner neighbor.

Notice the pattern: every pitfall is a case of trusting one signal in isolation. The free workflow in this guide exists precisely to cross-check content against authentication against reputation against placement, so no single misleading number drives a bad send. Discipline beats any one tool.

Troubleshooting: 10 deliverability test failures

When a test comes back wrong, the symptom usually maps to a specific cause. Use this table to jump from what you see to what to change. It covers the ten failures B2B senders hit most often across Mail-Tester, Postmaster Tools, and seed tests.

Two of these deserve extra caution. A No data found in Postmaster is not a pass, it is an absence of evidence, and senders read it as success far too often. And a 550 5.7.515 from Microsoft is a hard block, not a filter, which means the message did not reach the junk folder at all. Both trace back to the same root cause the free tests are designed to catch early: authentication that is missing, misaligned, or invisible to the provider until you are already sending at volume.

Advanced tips for more accurate free testing

Once the basics pass, these techniques make a free email deliverability test behave more like the expensive monitoring panels.

• Test at representative volume. One message tells you about content and authentication. Placement and throttling behavior only appear when you send at a realistic batch size, so seed-test a real segment, not a single email.
• Rotate and interact with seed inboxes. Providers weight engagement. Seeds that open, scroll, and occasionally reply reflect real placement better than dormant addresses that train filters against you.
• Test the rendered variant, not the raw template. Merge tags, dynamic blocks, and personalization change the final HTML. Send a version with tags resolved, because that is what SpamAssassin and the provider actually see.
• Split tests by sending stream. If marketing, transactional, and sales sequences use different IPs or subdomains, test each separately, because reputation is per stream, not per company.
• Automate re-tests before every send. GlockApps and Mail-Tester expose APIs. Wire a pre-send check into your deployment so a campaign cannot go out if the score drops below your threshold.
• Correlate the Postmaster spam rate with your ESP feedback loop. Feedback loops from providers give you per-campaign complaint data that Postmaster only aggregates. Reading both catches a bad creative before it moves the domain average.
• Add BIMI once DMARC is at enforcement. A BIMI record needs DMARC at p=quarantine or p=reject and displays your logo in supporting inboxes, which lifts recognition and, indirectly, engagement.
• Track time-to-inbox, not just placement. A message that lands in the inbox after a 20-minute deferral is a soft warning about reputation. EasyDMARC and GlockApps report receive time, so watch it trend.

None of these require budget. They require discipline and a repeatable process, which is where a lot of B2B teams choose to bring in help. Building a monitored, automated deliverability pipeline is a close cousin of the lead generation and outreach infrastructure that depends on it, since a cold sequence that lands in spam generates zero pipeline no matter how good the copy is.

The complete free deliverability audit project, end to end

Here is the entire workflow as one repeatable project you can run on any sending domain. It combines DNS verification, content scoring, reputation, and placement into a single pass, using only free tools. Start with a script that reads your authentication records in one command, so you are not typing three separate lookups every time.

#!/usr/bin/env bash
# free-deliverability-audit.sh DOMAIN SELECTOR
DOMAIN=$1
SELECTOR=${2:-selector1}

echo == SPF ==
dig TXT $DOMAIN +short | grep spf1

echo == DKIM ==
dig TXT ${SELECTOR}._domainkey.$DOMAIN +short

echo == DMARC ==
dig TXT _dmarc.$DOMAIN +short

echo == MX ==
dig MX $DOMAIN +short

echo Now send your real campaign creative to your mail-tester address and record the score.

Run it as ./free-deliverability-audit.sh example.com selector1. It prints your SPF, DKIM, DMARC, and MX records and reminds you to run the content and placement tests that cannot be automated from DNS alone. Then follow this cadence, which is the difference between a one-time score and durable inbox placement.

The project is deliberately boring, because deliverability rewards consistency. A domain that passes this audit before every send, monitors Gmail weekly, and keeps its complaint rate under 0.10% will sit in the inbox far more reliably than a domain that runs one heroic test and never checks again. If you want the cadence enforced automatically with alerting and reporting rather than run by hand, that is exactly the kind of growth and demand infrastructure worth systematizing.

What to do Monday morning

You do not need budget or a new vendor to start. You need 45 minutes and DNS access. Here is the order of operations for the next hour.

First, run the three dig commands from step one against your primary sending domain and read what comes back. Most deliverability problems are visible in those three lines: a missing DMARC record, an SPF that softfails, a DKIM selector that returns nothing. Second, send your most recent real campaign to a Mail-Tester address and read the deductions. Fix the authentication and infrastructure items today, because they carry the most weight and satisfy provider enforcement at the same time. Leave the content tuning for a second pass.

Third, add your domain to Google Postmaster Tools v2 if it is not already there. It takes one TXT record and gives you the only free view of what Gmail actually thinks of you. You will not see data for a day or two, which is exactly why you set it up now rather than the morning of a big send. Fourth, run one seed-placement test in GlockApps or the GMass tester so you can see Outlook and Yahoo, not just Gmail. If Outlook shows spam, your next task is Microsoft-specific authentication, because the 550 5.7.515 block has been live since May 5, 2025 and it rejects rather than filters.

Then make it a habit. Put the six-line cadence table on your team wiki, wire the audit script into your pre-send checklist, and re-test before every campaign that matters. A free email deliverability test is only worth the 10 minutes it takes if you run it before the send, not after the complaints. The inbox in 2026 is a compliance problem with a known answer, and the entire answer is available for free if you run it on schedule.

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