With my design skills the best I can come up with is a text logo in Gimp which looks really really bad. I've seen a lot of sites that show up with such a logo and it does not look good. Maybe to the technical HN crowd a logo doesn't matter, but a lot of people would be put off with a bad looking logo and that would definitely affect feedback and validation.

What is a logo? It's an aide-mémoire - a convenient shortcut for users to recognise and remember your company's image. When you have a strong brand a logo can be a phenomenal tool to keep your products in the public consciousness - but at the stage you're at now, a logo is just a small picture to put in the corner of a website. That's it.

Your company cannot survive without validation, and a logo (or lack of) is not stopping you getting that.

Google font the header.

Then go to fiverr and get a decent one for $5

Just do not add any logo at all. You imagine problems that are no problems at all.