Ask HN: So what happened to Facebook "localhost" tracking?

37 points by juliusceasar 2 hours ago | 45 comments

It was discussed a year ago. https://news.ycombinator.com/item?id=44235467

> Meta must face a lawsuit alleging that it secretly tracked Android users' browsing activity on mobile websites that embedded Meta's analytics pixel, and linked that activity to users' identities, a federal judge ruled Monday.

> The decision, issued by U.S. District Court Judge Rita Lin in San Francisco, grew out of a class-action complaint initially brought last June by California resident Devin Rose (and later joined by other Android users).

> Rose alleged that between September 2024 and June 2025, Meta exploited Android's localhost -- a feature that allows software developers to test applications -- to connect users’ mobile web browsing to their Facebook and Instagram profiles.

May 12, 2026

Retr0id 4 minutes ago | |

Not at all to defend Meta but "a feature that allows software developers to test applications" is a dubious definition of localhost. I also can't come up with a better one.

gruez 1 hour ago | |

docket: https://www.courtlistener.com/docket/70448987/in-re-meta-and...

woodrowbarlow 1 hour ago |

i would love to have a software engineer's union, not so much to get better working conditions but to be able to say stuff like "i can't implement that unethical feature, it's against union rules and i'd lose my membership".

grayhatter 32 minutes ago | |

To be fair; you don't need a union... you can just say no. Context; I told them they couldn't ship this exact feature as designed. (It worked until I left.)

woodrowbarlow 1 minute ago | | |

yes, true sometimes (not always). but if more people have access to a way to confidently say "no" (with protection behind them), then i think saying "no" would happen more often, by people who might've otherwise complied.

Trasmatta 22 minutes ago | | |

Without the protection of a union, "just saying no" is a good way to get fired

kube-system 7 minutes ago | |

I'd wonder how you'd get into that arrangement to begin with when the entire job is based on unethical tracking

volkercraig 1 hour ago | |

Start one. Unions are worker owned. You could also join the IWW.

woodrowbarlow 22 minutes ago | | |

are there examples of unions that have started around a focus on the ethics of the services they provide? unions traditionally start locally, around issues for which the locality is a hotspot, which is why they usually focus on pay and working conditions. it's also easier to get a large group to agree on a set of improvements to working conditions vs a set of ethical boundaries.

actionfromafar 57 minutes ago | | |

Unions in the US are nerfed, by law.

LadyCailin 20 minutes ago | |

That’s what licensing is for, not unions.

woodrowbarlow 8 minutes ago | | |

i don't believe that software development should require a license. imagine having to get board-licensed to download gcc; therein lies the death of free software and owning your devices.

hluska 13 minutes ago | | |

A union could absolutely get involved in something like this.

absqueued 1 hour ago | |

Take a lead, let me sign up :)

SoftTalker 1 hour ago | | |

And this is why we don't have one. Someone else is expected to do the hard part.

hasahmed 1 hour ago | | |

same

theodorejb 1 hour ago | |

You don't need to join a union to push back against unethical feature requests.

jakubadamw 56 minutes ago | | |

The collective leverage of a union gives you significantly more power to do something like this.

chrncirurp 55 minutes ago | | |

> You don't need to join a union to push back against unethical feature requests.

If you push back against unethical feature requests:

No union: you get fired

Union: you still get fired

ethagnawl 21 minutes ago | |

> not so much to get better working conditions but

... why not both?

mozvalentin 2 hours ago |

Chrome and Firefox have deployed / are deploying local-network-access which prompts the user when apps try this.

crtasm 14 minutes ago | |

I just discovered that MacOS was blocking Firefox from connecting to devices on my LAN - there's per-app toggle in system settings.

Access to my router's web interface was not blocked (understandably) but this left me rather confused for a while.

pezgrande 1 hour ago | |

I guess that's why I am getting so many "Allow to find devices on your network" alerts. Good feature overall.

SoftTalker 58 minutes ago | | |

Only a good feature if users have a clue what that question means. Most will click "Yes" because they want to get on with whatever they want to do.

Change it to something like "This website is trying to spy on your local devices, do you want to allow this?"

shit_game 1 hour ago | |

I was just about to say that my question in regards to this was "what are web browsers doing about it?"

Tade0 1 hour ago | |

I've seen it and at least in Chrome it seems to be treating all URLs which are based on an IP address as "local", regardless of the class of the address.

kibwen 1 hour ago | | |

I'd be inherently suspicious of any website in the wild attempting to contact a bare IP address. Aside from localhost, my default assumption would be that such a website is either trying to circumvent my hosts file (or circumvent my other DNS configuration, e.g. pi-hole or DNS-over-HTTPS), malware trying to reach a command-and-control server, or malware trying to circumvent my adblocker.

KomoD 2 hours ago |

Looks like they stopped doing it

https://localmess.github.io

> UPDATE: As of June 3rd 7:45 CEST, Meta/Facebook Pixel script is no longer sending any packets or requests to localhost. The code responsible for sending the _fbp cookie has been almost completely removed. Yandex has also stopped the practice we describe below.

throwa356262 1 hour ago |

Off topic: I wonder how hard it is to poison this type of data gathering?