100% Free & Privacy-Focused

Optimize & Verify Your
Email Infrastructure

Audits, lookup resources, and delivery sanitizers to secure your sending domain reputation and optimize email copy. Run checkups 100% in your browser.

18 Developer Tools
100% Local & Private
0ms API Latency

Free Email Utility Directory

Search or filter through our complete toolbox of developer and marketer resources

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Content

Analyze Text for Spam Indicators

Scan subject lines and bodies for trigger words, heavy capitalization, and code structures that trigger spam traps.

Audit

Detailed Multi-Layered Email Checker

Perform comprehensive validations: syntax validation, domain verification, and direct SMTP handshake simulation.

Discovery

Find Corporate Email Address

Analyze company domains to uncover corporate naming patterns and generate verified business emails.

Lookup

Reverse Email Lookup

Extract domain details, connected social media profiles, and registry logs from a single email address.

Outreach

Email Address Permutator

Generate combinations of names and domains to build valid arrays for cold sales outreach validation.

Reputation

Blacklist Checker

Scan domain and IP status against 80+ major email DNS blacklists (DNSBL) to verify delivery health.

Extractor

Crawl & Extract Emails from URL

Extract active email strings from HTML pages, internal links, or sitemaps using local parsing.

Score

Email & Domain Reputation Score

Obtain an email deliverability score based on SPF setup, DMARC alignments, and MX record trust.

Writing

Outreach Email & Sending Domain Generator

Generate highly personalized outbound copy templates while validating cross-domain DMARC policies.

Testing

Gmail Dots & Plus Trick Alias Generator

Create hundreds of dummy test alias emails from a single address using standard dot and plus syntax configurations.

B2B Lookup

Corporate Email Finder from LinkedIn

Permute names and business domains to extract verified active profiles from target LinkedIn lists.

Sanitize

Remove Duplicates from List

Instantly remove duplicate emails, lines, and domain values from messy target subscriber copy lists.

Utility

Mailto Link Generator

Generate URL-encoded HTML mailto links complete with pre-filled CC, BCC, subjects, and text bodies.

Analytics

Email Size & Readability Analyzer

Audit size benchmarks to prevent Gmail body clipping, and compute standard text readability levels.

SMTP

SMTP Server Configuration Tester

Verify connection parameters, handshake response speeds, and active authentication ports on mail relays.

SPF

Validate SPF Domain Records

Decode SPF syntax layouts, check domain authorizations, and monitor the critical 10-lookup limit threshold.

Formatting

HTML to Clean Plain Text Converter

Strip HTML layouts to generate readable text variants, crucial for secondary multipart content delivery.

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Secure & Performant Design Architecture

Why engineers and growth marketers rely on Mail Tool Hub for deliverability checkups

Privacy Guaranteed

No network payloads check your subscriber lists. Standard JS libraries parse calculations inside the sandboxed browser context.

Instant Auditing

Experience zero loading circles, server queues, or waiting lists. Simply paste domains and obtain real-time validation results.

Developer-First Specs

Inspect structural syntaxes directly. We decode TXT configurations, SPF lookup logs, and server headers transparently.

Frequently Asked Questions

Everything you need to know about domain deliverability and email formatting

How do these tools verify my domain without charging a fee?
These utilities run locally inside your browser client, utilizing standard DNS resolution APIs and local text parsing. By reducing server hosting overheads, we are able to provide these developer tools entirely free without limits.
What is the 10-lookup limit in SPF verification?
The SPF RFC specification limits the number of DNS lookups a mail server can perform during verification to 10. Exceeding this limit causes SPF validation failures (PermError), which reduces your sender deliverability. Our SPF validator decodes and highlights nested includes.
Is my list data stored on your servers?
Absolutely not. All operations (e.g. duplicate removing, text spam cleaning, and mailto generation) are handled exclusively within your local memory context. None of your data is ever transmitted to a database.
What are the key spam indicators checked by the analyzer?
Our Spam Indicator tool audits your text against high-risk words (e.g., "guaranteed", "free cash", "buy now"), checks capitalization-to-lowercase ratios, flags spammy subject line patterns, and verifies overall link density.
How does the LinkedIn corporate email finder work?
The LinkedIn corporate email finder uses standard naming structures (like `[email protected]`, `[email protected]`) combined with domain records to generate possible contact formats. It helps outreach managers build target profiles accurately.