Free email tools
for developers
Inspect MX records and raw headers, validate SPF, DKIM, and DMARC, verify addresses, run spam tests, and turn markdown into email-safe HTML — all without creating an account.
The toolbox.
Every email utility you're likely to need — no account, no caps.
- 01Markdown to Email
Turn rich text into email-safe HTML using a visual editor with a live preview.
Open tool - 02Email Verification
Check any address in seconds — DNS and MX configuration, likely typos, and throwaway domains.
Open tool - 03Spam Checker
Run your subject line and body copy through common spam-filter signals before you hit send.
Open tool - 04SPF Checker
Fetch and analyze a domain's SPF record. Spot problems before they cost you deliverability.
Open tool - 05DMARC Checker
Inspect a domain's DMARC policy and reporting setup, with guidance for reaching full enforcement.
Open tool - 06DKIM Checker
Fetch the DKIM public key for any selector and confirm it's live and properly set up.
Open tool - 07MX Record Checker
Query a domain's mail exchangers, review their priorities, and troubleshoot delivery issues.
Open tool - 08Email Headers Analyzer
Drop in raw headers to decode SPF/DKIM/DMARC outcomes, every routing hop, and the whole authentication chain.
Open tool - 09Deliverability Score
Score your domain across SPF, DKIM, DMARC and MX — and see exactly what's hurting your inbox placement.
Open tool - 10Bulk Email Verifier
Paste a list and check syntax, MX and disposable/role addresses in one pass. Clean your list before you send.
Open tool - 11SPF, DMARC & DKIM Generator
Build valid SPF and DMARC records and generate a DKIM key right in your browser — copy-paste into your DNS.
Open tool - 12Email Cost Calculator
Compare your Klaviyo or Mailchimp bill to Bitelio and see what you'd save — priced on sends, not contacts.
Open tool - 13Email Template Builder
Build an email with blocks and export clean, email-safe HTML — no account needed.
Open tool - 14Email Preview Tester
Preview your HTML on desktop and mobile and lint it for Gmail, Outlook and Apple Mail rendering issues.
Open tool - 15SMTP Server Test
Check an SMTP server's connectivity, TLS and EHLO capabilities. No login, no sending.
Open tool - 16Blacklist Checker
Check an IP or domain against Spamhaus and other DNSBLs to catch reputation problems early.
Open tool
Made by email nerds, always free.
No accounts, no paywalls — just utilities shaped by people who ship email for a living.
Free forever
Run every tool as often as you like — there's no registration, no paywall, and no usage cap.
Developer-focused
Made by people who wrangle email daily: tidy output, immediate results, and workflows that match real projects.
Production ready
Validation follows industry standards, and the generated HTML renders cleanly in every major email client. Thousands of sends have proven it.
Ready to send for real?
Templates, automation, scheduling, analytics, and deliverability in one platform. Free to start, priced to grow with you.