Hey fellow self-horders!
I built mailcheck — a free, open-source tool that checks all 6 email authentication protocols (SPF, DKIM, DMARC, MTA-STS, TLS-RPT, BIMI) for any domain and gives you a 0–100 deliverability score.
Try it: https://korpo.pro/ — type any domain and get instant results.
Self-host it: It’s MIT licensed with a FastAPI backend. pip install mailcheck or clone from our Forgejo repo.
CLI: mailcheck example.com — great for CI/CD integration (exit code 2 on critical issues).
API: curl https://korpo.pro/api/v1/check/example.com — no auth needed, 100 req/hr.
Batch mode: mailcheck --file domains.txt
I found that many well-known domains have misconfigurations — even big crypto projects. The tool helped me fix my own domain’s email auth setup.
Would love feedback from email/infra folks!
Shows a failure if the DKIM selector isn’t on an arbitrary list? What’s going on there?
Yah, I don’t think this is working. It’s failing spf and dkim records that have worked for years
Interesting. I’m getting full marks on mxtoolbox but failing the same tests on this one.
Firefox 149.0.2 (64-bit), Linux Mint, using VPN. I must have settings that are blocking the processing of the domain for whatever reason. I’ve tried multiple domains including well known domains. No joy. Sorry about that.
