IT
OmnvertImage • Document • Network

SPF / DKIM / DMARC Checker

Validate TXT records and highlight common misconfigurations.

What to look for

  • SPF: a single record, terminal policy (~all or -all), DNS lookups ≲ 10.
  • DKIM: correct selector and a published public key (p=...).
  • DMARC: p=quarantine/reject for enforcement, rua= for reports, alignment (adkim/aspf).

About

Email authentication depends on correct DNS records. This checker helps you validate SPF, DKIM and DMARC so you can improve deliverability and reduce spoofing risk. It’s useful when emails go to spam, authentication fails, or you’re setting up a new sending domain.

The tool reads the relevant DNS records and presents them in a more readable way. You can quickly see whether records exist, whether syntax looks valid, and whether policies are strict enough for your needs.

Remember that providers have different interpretations and additional heuristics. Use this tool as a fast diagnostic step, then test with your mail provider and examine sending logs for final confirmation.

SPF / DKIM / DMARC Checker is designed to be straightforward: pick your input, choose the output settings, and generate a result you can copy or download. We focus on predictable defaults so you can get a usable output quickly, then fine-tune only when you need to.

If you’re using this tool for work, treat the result like any other export: verify a small sample first, then run the full job. Small checks (file size, encoding, preview, or a spot-check of values) prevent surprises later when you publish, upload, or share the output.

Quality and compatibility often pull in different directions. When you want maximum compatibility, choose widely supported options. When you want smaller size or faster delivery, pick modern formats and compression settings—but keep an original copy so you can re-export without compounding losses.

Privacy matters. Some tools run fully in your browser, while others may need server-side processing (for heavy conversions or specialized libraries). Where uploads are required, keep files non-sensitive and avoid including secrets in inputs. Always review the final output before sharing publicly.

Troubleshooting tips: if the output looks wrong, try changing one setting at a time, and confirm your input is what you think it is (color profile, transparency, encoding, delimiters, or line endings). Many issues come from an unexpected input variant rather than a broken converter.

For best UX, we keep the interface minimal and the results easy to copy. If you’re on mobile, prefer shorter inputs and smaller files, and use Wi‑Fi for large uploads. On desktop, batch workflows are usually faster and easier to verify.

A practical workflow looks like this: (1) start from the highest-quality source you have, (2) run a quick test with default settings, (3) adjust only one parameter at a time if needed, and (4) validate the output in the place it will actually be used (website, app, email, print, or a media player). This keeps results consistent and makes it clear which setting caused which change.

If you repeat the same task often, consistency is more valuable than tiny optimizations. Use stable naming (include format, size, and date in the filename), keep a “known good” sample for comparison, and save your preferred settings as a habit. When exporting multiple items, process them in small batches so you can spot problems early.

FAQ

What is SPF?
SPF is a DNS TXT policy that declares which servers are allowed to send email for a domain.
What is DKIM?
DKIM signs outgoing mail with a cryptographic key. The public key is published in DNS and used to verify authenticity.
What is DMARC?
DMARC ties SPF and DKIM together and tells receivers what to do when authentication fails (none/quarantine/reject).
Why do changes not show up immediately?
DNS caching and TTL can delay visibility. Check propagation and allow time after updates.
Does this guarantee inbox placement?
No. It helps validate core authentication, but reputation, content, and engagement also affect placement.
Is it free to use?
Yes—this tool is free to use. Usage limits may apply for very large files or extreme workloads.

Related Tools