You ask for permission from your contact/champion at the company, or at contract time. You might offer a discount if you’re in contract negotiations.

Getting permission is definitely not a sure thing and might require some luck or savvy, or having a champion with clout (director, VP, etc…)

It’s also very common for a small team (or individual) at a large company to use a tool, and the tool can plaster that logo on their homepage even if the use case was insignificant.

For a lot of companies, logos on homepages is more of an “ask for forgiveness later” type of thing. Not uncommon to do it without permission.

It’s also very common for TOS to include the rights to use your company logo for marketing purposes by default.

For us, every single one of the logos we display on https://retool.com has a committed contract with Retool where they agreed to display their logo. (Generally our champion does need to go ask a VP; in return we offer a discount.) 100% of the logos that we show pay us more than $50k a year. (80% of them pay us more than $100k a year, and some % of them pay us more than $1M a year, hah.) We wouldn't want to display their logo otherwise! (Since it'd be misleading, but also because it'd be problematic — if say — Taco Bell engineer came and asked us who exactly is using Retool at Taco Bell.)

(Founder at Retool here.)

that's awesome. Just a thought, I wonder if users would appreciate knowing that. To me, the reason I asked is I tend to assume the worst (minimal permission, 1 person in the org, no contract, etc...). Maybe just me, but especially so when it's huge names like Amazon or Stripe

I've seen SaaS providers engage in really scummy practices here. Like comb through their access logs or user databases, find that someone signed up from an IP address belonging to a corporate ASN, and then putting that company's logo on their website as a user/customer. Technically telling the truth, but with information obtained in a really shady manner.

(I'm not claiming Retool does or does not do this.)

Google "[company] logo", download the image and add it to your website.

You need to be an insider. Like maybe your sister is married to a big tech CEO or your parents own a lot of big tech stocks. Any personal/family connection will do.