Note: please contact me securely if it’s about a security issue in some code that I’ve written.


The easiest way to reach me is probably via email. If you want to chat about something personal then address emails to <charlie [at] charliejonas [dot] co [dot] uk> however queries and comments relating to my website should be directed towards <webmaster [at] charliejonas [dot] co [dot] uk>. Before you email me however, I have a few requests:

  1. Please don’t send me an email attachment in a proprietary format (for example .docx .xls .ppt et cetera). Acceptable email formats are HTML or plaintext. Acceptable attachments are plaintext, html, PDF, Markdown, LaTeX or maybe ODF at a push.
  2. Write to me on one email account only. I get email from all my accounts on every device and nobody wants four copies of the same note.
  3. Please protect my privacy, as well as yours. Don’t give my email address to an invitation service. If you want to share a link with me, send it yourself instead of clicking the “email” button on the web site.
  4. No matter how good the cause, do not add me to any kind of mailing list. These email addresses are for individual correspondence only.
  5. The UK uses the UTC+0 time zone and goes to UTC+1 during the summer (from the last Sunday in March to the last Sunday in October). Please factor this in when awaiting replies to correspondence.

Instant Messaging

If prefer not to use Facebook Messenger for anything other than personal correspondence. Please add me to your Slack group or similar for work-related issues.

I’m happy to use WhatsApp and iMessage for casual messaging although you’ll need my mobile number for these. This can be retrieved through running WHOIS on my domain.

Not unsolicited calls please, except in an emergency.

Postal Service

My home mailing address should be reasonably easy to figure out through some searching of the WHOIS database if you’re desperate enough.


I’m active on the radio airwaves as M0ZCJ so feel free to attempt a contact that way. When in Cambridge I usually tend to listen in to GB3PY & GB3PI (note that PY has a connection to the worldwide Echolink network). I prefer analogue FM on 2-metres for local contacts but I am increasingly interested in DMR. I also hold a Simple UK Light Business Radio License from Ofcom and am happy to converse on those frequencies or PMR446 if you do not hold a radio license yourself.

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