RoboKiller vs Nomorobo vs Scammer Guardian: 2026 Comparison

Three of the most-searched scam call apps in 2026 are RoboKiller, Nomorobo, and Scammer Guardian. They all want to stop your aging parent from being scammed, and they all show up in the same App Store search. They take very different routes to get there.

This is the side-by-side. Pricing, App Store reviews, what each one actually catches, what it costs in dollars and friction, and the one architectural difference that decides which family each one is right for.

Compare all 8 apps in one table on the hub page

The one-line summary

App	Method	Price/mo	App Store reviews
RoboKiller	Blocklist + answer-bot decoys	$4.99	413,000 (4.5 star)
Nomorobo	Simultaneous-ring blocklist	$1.99 to $4.17	21,000 (4.5 star)
Scammer Guardian	Pre-call AI conversation screening	$29 to $39	Just launched (May 2026)

The price gap is real, and so is the technology gap. Cheap blocklist matching costs almost nothing per call. Running a live AI conversation with every unknown caller has a real per-call cost. We'll get to whether that's worth it for your family, but first, here's what each one actually does.

What RoboKiller actually does

RoboKiller markets itself as the app that "gets revenge" on telemarketers. Its core technology is two-part: a large blocklist of known robocall numbers (similar to Nomorobo), and "Answer Bots," a library of recorded characters that pick up suspected scam calls and try to waste the scammer's time.

Strengths:

• Massive App Store presence. 413,000 reviews at 4.5 stars is real market validation, even after you discount review-incentive programs.
• The Answer Bot gimmick is genuinely entertaining. Some users actively enjoy listening to recordings of "Trump Bot" or "Boomer Bot" stringing scammers along.
• Stops a high volume of bulk robocalls because the blocklist is so large.
• $4.99 per month is in the same range as a Netflix subscription. Easy yes on price.

Weaknesses:

• The Answer Bot is for entertainment, not protection. By the time it kicks in, the call has already been classified as "probably spam" by the blocklist. If the blocklist missed a number (a new scammer, a spoofed local number, a live human script reading from a freshly-purchased lead list), no bot triggers and the call rings through.
• Live human scammers, especially the IRS impersonators, grandparent-scam callers, and Medicare verification fraudsters who target seniors, bypass blocklist matching entirely because they use rotating spoofed numbers.
• The user has to opt in to "block on suspicion." Many users don't, fearing legitimate calls get blocked, so the phone still rings on suspected scams (with a label) and they still pick up.

Best fit: Younger consumers who get a lot of bulk telemarketing and want a cheap, entertaining defense layer. Not architected for the senior-protection use case.

Read the long-form Scammer Guardian vs RoboKiller comparison

What Nomorobo actually does

Nomorobo is the original. It won the FTC's 2013 Robocall Challenge by inventing the "simultaneous ring" trick: when a call comes in, your phone and Nomorobo's servers both ring at the same time. Nomorobo's server checks the number against its blocklist; if it's a known bad number, Nomorobo hangs up before your phone can ring a second time. From the user's perspective, scam calls show one short ring and then silence.

Strengths:

• Cleanest, simplest user experience of the three. No labels, no decisions, no app to open. Calls just stop.
• $1.99/mo (mobile) to $4.17/mo (annual) is the cheapest paid option in the category.
• Built into many carriers and VoIP providers natively, often free.
• Honest about what it is: a blocklist with a clever delivery mechanism.

Weaknesses:

• Like RoboKiller, only catches numbers already in the blocklist. New scammers and live humans on rotating numbers get through.
• The simultaneous-ring trick only works on phone systems that support call forwarding tricks; some carrier configurations don't.
• iPhone implementation works through the Call Directory extension, which is more limited than Android's deeper carrier integration.

Best fit: Scam-aware seniors and adult households who want a "good enough" cheap defense against bulk robocalls. Not designed for protected-person scenarios where a single missed live-human scam can cost tens of thousands of dollars.

Read the long-form Scammer Guardian vs Nomorobo comparison

What Scammer Guardian actually does

Scammer Guardian takes a different architectural route. When an unknown number calls the protected phone, the call doesn't ring the senior's device at all. It rings an AI screener first. The AI picks up, asks the caller who they are and why they're calling, listens to the answer, and decides whether the caller is legitimate. Real callers ("Hi, this is Linda from the church") get identified and the call rings through normally. Scammers trying to deliver a script get the call ended. The senior never hears the scammer's voice.

Strengths:

• Catches what blocklists fundamentally cannot: live human scammers using rotating spoofed numbers. No database lookup. The AI is evaluating the actual conversation in real time.
• The senior never has to make a judgment call in the moment. There's no "Scam Likely" label to ignore, no decision to override. The phone simply doesn't ring on a scam call.
• Real-time SMS alert to a designated guardian on every blocked attempt. Quiet daily summary at 8 AM. The family has full visibility without monitoring 24/7.
• Whitelisting works as expected: family, doctors, the pharmacy all ring through instantly without the AI prompt.

Weaknesses:

• $29 to $39 per protected line is meaningfully more than $4.99. The cost reflects the per-call AI compute, but it's still a real difference for cost-sensitive families.
• New legitimate callers (a doctor's office calling for the first time, a delivery driver) have to identify themselves at the AI prompt, which is a brief one-line interaction.
• Requires a five-minute setup on the protected phone, configuring call forwarding. Not zero-friction the way a freemium blocklist app is.

Best fit: Families where the senior would still pick up a "Scam Likely" labeled call. Anyone who has already been scammed once. Any household where a single missed live-human scam call would do serious damage. This is what pre-call AI screening is built for.

The architectural difference, in plain terms

The cheap, popular apps (RoboKiller, Nomorobo, and most of their competitors) work by checking a list. The list of known bad numbers is huge. Most bulk robocalls match it. Most scam-detection wins they describe are blocklist matches.

But the scams that actually cost seniors the most money are live human conversations, not robocalls. The IRS impersonator who threatens arrest. The "grandson" who says he's in jail and needs bail money. The "Medicare verification rep" who asks Mom for her Medicare number. These callers rotate their numbers constantly. The number you see today won't be on any blocklist tomorrow.

A blocklist cannot stop a call from a number that isn't on it. That's not a knock on the technology; that's the technology working as designed. It's just a different problem than what's harming seniors most.

Scammer Guardian's pre-call AI screening engages with the caller in real time, in conversation. It doesn't matter whether the number is on a list. It evaluates the actual content of what the caller says in the first ten seconds. That's the architectural shift.

Which one for which family?

Honest framing:

• Your parent is scam-aware, dismisses obvious nonsense, occasionally annoyed by robocalls? RoboKiller or Nomorobo. The cheap blocklist apps will reduce volume by a meaningful percentage. The remaining calls your parent will recognize and ignore on their own. No need to spend $29.

• Your parent picks up every call regardless of caller ID or warning label? Pre-call AI screening (Scammer Guardian). The architecture matters here. Labels and blocklists are not what's failing this family; the act of picking up is.

• Your parent has already been scammed once? Almost certainly Scammer Guardian. Scam victims' numbers go on "sucker lists" that get sold to other scammers, and call volume from live-human scams rises sharply afterward. A blocklist will not catch most of what comes next.

• Your parent is in early cognitive decline, or you're not sure whether they'd recognize a sophisticated impersonation in the moment? Scammer Guardian. The whole point of pre-call screening is that the senior never has to make the recognition call themselves.

• Tight budget, sharp senior? Free carrier-level Hiya labeling plus Nomorobo at $1.99/mo is a defensible layered combo. Add Scammer Guardian if any of the higher-risk conditions above become true.

What about combining them?

You can absolutely run Scammer Guardian alongside RoboKiller or Nomorobo, and many of our customers do. They sit at different layers:

• Scammer Guardian intercepts unknown callers before the phone rings.
• A blocklist app (or carrier-level Hiya labeling) provides extra context on any number that does get through Scammer Guardian's screen.

The combination doesn't conflict. We don't actively recommend paying for both Nomorobo and RoboKiller (they overlap significantly in what they catch), but layering one of them under Scammer Guardian is fine.

Bottom line

RoboKiller is a popular, entertaining, cheap defense against bulk robocalls. Best for general consumers with telemarketing fatigue.

Nomorobo is the clean, quiet, cheapest option in the category. Best for adult households and scam-aware seniors who want low-friction call filtering.

Scammer Guardian is the active interception layer built for the protection scenario blocklists fundamentally cannot solve: a senior who will pick up the call, and a live human scammer on the other end. It costs more because the underlying AI conversation costs more. For active scam targets and families who have already been hit once, that math is straightforward.

If you're in the latter group, start the seven-day free trial, or grab the app directly on the App Store or Google Play. Fourteen-day money-back guarantee after the trial. Cancel anytime from your dashboard.

If you're not sure which group you're in, the full comparison hub lays out all eight serious apps in one sortable table, and the Recovery Playbook is the right read if a scam has already landed.