How to see someones messages?

Reliably is the wrong variable — authorization is. If the phone is yours or belongs to a minor you administer, you can read its messages; if it belongs to another adult, the only reliable routes are their consent, a court order, or a licensed investigator. No app changes that, and any tool promising otherwise is selling you a credential phishing page.

Full disclosure: we build Ultimate Phone Spy, which runs on Android 4.0+, Windows and Mac and includes SMS, call-log and web-history capture from one dashboard (sms tracker, system requirements). It has no iPhone support, because iOS gives no device-level access to message content — so any product claiming live iMessage reading from a dashboard is not telling you the truth.

Start with the free, first-party options:

1. Your own Android phone. Messages are in your Google account backup; Google Takeout exports them. No purchase needed.
2. A child's Android. Google Family Link manages the account and lets you approve apps, but it does not show message bodies. That gap is the honest reason a paid dashboard exists.
3. An iPhone in the family. Screen Time shows who they contact and lets you set communication limits, not the content of the messages.

On the legal line, plainly: in the US, reading another adult's messages without consent can breach the Wiretap Act and state privacy statutes even on a shared family plan; in the UK and EU the equivalents are the Computer Misuse Act and GDPR. The evidence is frequently inadmissible in the case it was gathered for, and the act itself becomes the counterclaim.

The longer version, including the partner-phone scenario, is in this thread.