Free email tools
Email testing, domain health, deliverability, and DNS tools
Use these free MailSlurp tools to verify sender setup, diagnose delivery issues, audit message quality, and create disposable inboxes for QA. The hub is organized around the real jobs teams do: publish sender DNS safely, debug mail failures faster, and ship cleaner email before the release window closes.
Coverage
32 tools
Free checks across sender auth, deliverability, content QA, and test inbox workflows.
Structure
4 workflow lanes
Start with the workflow you need to check, then open the tool that answers that exact question.
Primary use
Faster troubleshooting
Check domains, messages, and infrastructure before launches or during incidents.
Conversion path
Free check to product
Every lane connects the free check to the MailSlurp workflow that makes it repeatable.
Intent-led tool hub
Start with the job, then move into the exact check
Primary paths
Fix sender authentication
Start with SPF, DKIM, DMARC, and domain-health checks when a domain change, migration, or enforcement rollout is planned.
Audit a message before send
Use pre-send QA tools when one broken link, missing image, or invalid HTML block can affect activation, billing, or lifecycle performance.
Investigate inbox problems
Move into headers, blacklist checks, inbox placement, and reverse DNS when delivery or trust is already in question.
Create a safe test environment
Use disposable inboxes and setup helpers when QA or automation needs isolated mailboxes instead of production addresses.
What the section covers
Problem lanes
4 jobs
Structured around sender auth, diagnostics, content QA, and safe test environments.
Conversion path
Free check to product workflow
Each lane connects the free diagnostic to the MailSlurp capability behind it.
Quick start
Fix sender authentication
Start with SPF, DKIM, DMARC, and domain-health checks when a domain change, migration, or enforcement rollout is planned.
Quick start
Audit a message before send
Use pre-send QA tools when one broken link, missing image, or invalid HTML block can affect activation, billing, or lifecycle performance.
Quick start
Investigate inbox problems
Move into headers, blacklist checks, inbox placement, and reverse DNS when delivery or trust is already in question.
Quick start
Create a safe test environment
Use disposable inboxes and setup helpers when QA or automation needs isolated mailboxes instead of production addresses.
Product path
Use the free tool hub as the front door to deeper MailSlurp workflows
The best tool pages do not stop at the check itself. They answer the immediate question, then make the upgrade path obvious when the job needs saved history, repeatable automation, and clearer ownership.
Recommended next moves
Saved checks
Move from one-off tools into shared operational history
Free tools answer the first question. MailSlurp workflows keep the evidence, owners, and rerun history available for future launches and incident reviews.
Automation
Promote diagnostics into CI, launch gates, and sender reviews
The strongest workflows run before campaigns, releases, and migrations so auth drift, broken markup, or deliverability risk is caught before traffic starts.
Team visibility
Give platform, QA, and deliverability owners one common view
Keep MailSlurp checks connected to the teams that need them instead of distributing screenshots and ad hoc notes across Slack threads.
Use case
Domain auth and DNS
Use these tools when you are publishing sender records, validating a migration, checking domain health, or confirming whether mailbox providers can see the DNS state you expect after a change.
Tool 1
Domain monitor
Run a one-shot domain health check that scores SPF, DMARC, enforcement, and MX posture together.
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Tool 2
Email auth checker
Run SPF, DKIM, DMARC, BIMI, MX, MTA-STS, and TLS-RPT checks together for one sender-domain verdict.
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Tool 3
DNS lookup
Start here to troubleshoot SPF, DKIM, DMARC, MX, and routing issues.
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Tool 4
DNS propagation checker
Verify when SPF, DKIM, DMARC, and MX DNS updates are fully visible.
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Tool 5
DMARC checker
Validate DMARC policy, alignment, and reporting configuration.
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Tool 6
DMARC domain lookup
Fetch DMARC DNS records and inspect warnings, tags, and validity.
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Tool 7
DMARC record generator
Create DMARC TXT record values with policy and reporting tags.
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Tool 8
DMARC record validator
Validate required DMARC tags with a pass/fail checklist.
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Tool 9
SPF checker
Check SPF DNS records and validate authorized senders for your domain.
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Tool 10
SPF record generator
Generate SPF TXT record values with safer rollout guidance.
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Tool 11
DKIM checker
Validate DKIM TXT records and selector configuration for signed mail.
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Tool 12
DKIM record generator
Generate DKIM selector records for signed email setup.
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Tool 13
MX lookup
Check MX DNS records for a domain and verify email routing.
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Tool 14
BIMI checker
Validate BIMI readiness requirements and jump into live DNS checks.
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Tool 15
BIMI domain lookup
Run a direct BIMI DNS lookup for live record validation.
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Tool 16
BIMI record generator
Generate BIMI TXT values for branded sender logos.
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Tool 17
MTA-STS checker
Verify MTA-STS DNS policy and .well-known policy file.
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Tool 18
MTA-STS record generator
Generate MTA-STS DNS and policy-file content.
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Tool 19
TLS reporting checker
Validate TLS-RPT DNS records for SMTP TLS report delivery.
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Tool 20
TLS reporting record generator
Build RFC 8460 TLS-RPT TXT values for your domain.
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Use case
Deliverability diagnostics
Start here when a message lands in the wrong folder, fails authentication, or behaves differently across providers after a release or template change.
Tool 1
Email header analyzer
Analyze raw email headers to troubleshoot routing, auth, and deliverability.
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Tool 2
DMARC report analyzer
Summarize aggregate DMARC XML reports into alignment, disposition, and top-source views.
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Tool 3
Email spam checker
Run a spam-risk checklist across authentication, content, and headers.
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Tool 4
Reverse DNS lookup
Validate PTR records and sender infrastructure identity.
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Tool 5
SMTP tester
Check server connectivity, STARTTLS negotiation, and SMTP authentication.
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Use case
Content, rendering, and pre-send QA
Use this section before launch when your team needs to confirm that a template renders as expected across mailbox clients, does not ship broken markup into production, and passes a practical pre-send audit.
Tool 1
Email audit tool
Run a one-shot email audit across links, images, spelling, compatibility, and HTML validation.
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Tool 2
Campaign probe
Paste campaign HTML or text to catch broken links, asset issues, and compatibility risks before send.
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Tool 3
Email client compatibility checker
Analyze HTML email feature support across mailbox clients.
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Use case
Sender reputation and inbox placement
Use these tools when stakeholders ask whether messages are reaching inboxes, whether your sending infrastructure looks healthy, or whether reputation issues are throttling delivery.
Use case
Test inbox and setup utilities
Choose these utilities when you need a disposable evaluation flow, a private inbox for QA, or a quick setup helper while wiring email automation into test and staging environments.