Apps That Automatically Block Spam and Scam Calls: Hiya, RoboKiller, and Nomorobo

Robocalls and scam calls have become a daily frustration for most Americans. These are automated or live calls trying to trick you into giving up personal information, sending money, or pressing a button that leads to more scam calls. The FTC reports billions of robocalls are made every month in the United States.

Call-blocking apps work by checking incoming phone numbers against large databases of known spam and scam numbers. When a flagged number calls you, the app either silences the call, sends it to voicemail, or plays a message telling the caller they must verify they are a real person — which robocalls cannot do.

Three popular options are Hiya, RoboKiller, and Nomorobo. Each works on both iPhone and Android.

Hiya is free and identifies spam and fraud calls. It labels suspected spam calls on your screen so you can decide whether to answer. It does not automatically block calls in the free version. But it gives you enough information to decide.

RoboKiller goes further — it not only blocks robocalls but can also "answer bot" the calls, playing a recorded response that wastes the scammer's time while they are trying to call real people. It has a free trial and then costs about $4 per month.

Nomorobo offers a free version for landline phones through your phone carrier's website. For cell phones, the Nomorobo app is available with a subscription. It is straightforward and widely used.

All three services can block a call while still allowing it to be recorded in your call history. So you can still check if a legitimate call was blocked and return it.

None of these apps have access to your calls, voicemails, or messages. They only check the phone number against a database.