A complete guide to smart speaker privacy

Smart speaker privacy is a major concern for many modern households. Yes, they’re convenient and useful for smart home control. However, accidental recordings and technical vulnerabilities can make you second-guess what you say even in your own home.

While some manufacturers have improved privacy controls and use on-device processing, there are still important risks to consider. This guide breaks down the key smart speaker privacy concerns (with real-world examples) and steps you can take to stay safer.

Main smart speaker privacy issues

If you use a smart speaker daily, it helps to know what the device records, where it sends data, and how the company uses it. The next sections explain the basics.

How much data do smart speakers collect?

Your device can collect voice data, account and location info, and smart home activity. If you care about smart speaker privacy, you’ll want to know what gets logged:

• Voice clips and speech-to-text logs: Smart speakers may save short audio clips after the wake word and turn them into text transcripts. Depending on your model and settings, you can review, delete, or stop saving them.
• User profiles and account IDs: The assistant can tie requests to your account, your household, or a specific device. This helps with personalization, but it also makes it easier to track your voice activity over time.
• GPS, network, and address data: Smart speakers can use your home address, Wi-Fi network info, and location signals from linked devices. That can improve local results, but it also adds more personal data to your profile.
• Synced contacts from linked accounts: If you connect your phone or email account, the assistant may pull in your contacts. That makes calling and messaging easier, but it also exposes personal details if someone else uses the speaker.
• Search history and usage logs: The speaker can keep a record of what you ask, when you ask, and how you use its features. Providers may use this to improve responses or suggest content based on your habits.
• Smart home device data and usage patterns: If you connect lights, locks, or thermostats, the system can log your device activity. Over time, this can reveal routines, such as when you’re home, asleep, or away.

Related: Is Siri/Alexa listening to your conversations?

Can smart speakers identify you personally?

Anything Alexa, Google Assistant (now Gemini for Home in select countries), or other voice assistants pick up is tied to your personal account and settings. Of course, that’s not the same as knowing your name from your voice alone. All it means is that the recordings and commands can end up saved under your profile, along with your history and preferences.

Apple’s approach with Siri works differently. Instead of matching requests to your Apple ID or email, it uses a random code created by the device to label your Siri requests. This means the assistant knows about the voice query but doesn’t link it back to your personal account.

How do smart speakers process your requests?

Smart speakers process your voice data differently depending on the company and model, and not all of them prioritize privacy. Here’s how the big three do it:

• Google: With the rollout of Gemini for Home, local on-device processing for anything beyond basic wake-word detection is very limited or non-existent on most Nest speakers/displays. Almost everything (including simple commands) now goes to the cloud for Gemini processing.
• Amazon: Alexa detects the wake word on the device, then streams voice data to Amazon’s cloud for processing. As Amazon added generative AI capabilities to Alexa, the company decided to completely remove the option for local voice processing as of March 28, 2025.
• Apple: Siri handles a larger share of requests on-device, especially on newer iPhones, iPads, and HomePods with Apple silicon. This includes dictation and common commands. When cloud processing is needed, Apple typically uses a randomized device identifier rather than a persistent account-based link.

How voice recordings are stored and reviewed

Once Bloomberg, The Guardian, and VRT NWS broke the news in 2019 that Google, Amazon, and Apple used human reviewers to rate smart speaker voice clips to train their algorithms, people were understandably upset.

Leaked Google Assistant clips even contained addresses and other sensitive information, which is how VRT NWS was able to contact affected users in the first place. After the backlash, all three companies updated their practices (though not always for the better).

Here’s where things stand now:

• Google: By default, Gemini for Home voice activity is stored in Home History (auto-deletes after 18 months). You can turn it off or change the retention period (3/18/36 months) at any time. Google uses some of this data for AI training, and trained human reviewers may access some interactions. Even when turned off, Google still keeps your voice queries for up to 24 hours to provide the service, maintain safety/security, and process feedback.
• Amazon: Added an option that blocks stored Alexa recordings from being used for training.
• Apple: Stopped storing Siri audio by default and limited reviews to Apple staff if you happen to opt in.
• Sonos: Sonos Voice Control processes all voice commands locally on the speaker with no audio or transcripts sent to the cloud. Because of this on-device design, there is no voice history stored by Sonos, no data used for AI training or advertising, and no human reviewers involved.

Is your smart speaker data stored locally or in the cloud?

Each smart speaker platform has a different default for voice storage. Here’s how Google, Amazon, and Apple manage recordings:

• Google: By default, Google doesn’t save Assistant audio recordings. If you opt in, it stores voice recordings and transcripts in your Google Account. You can turn off saving and delete past Google Assistant activity or Gemini Apps activity at any time.
• Amazon: Unsurprisingly, Amazon saves Alexa voice recordings after processing them in the cloud. You can manage this through the Alexa Privacy settings, such as enabling automatic deletion after 3 or 18 months or disabling saving entirely, which removes recordings after they’ve been used to handle the request.
• Apple: Unless you opt in, Apple doesn’t store Siri audio. Even then, Apple only links recordings to a random identifier and lets you delete your history from its servers at any time. That said, you can’t delete already-reviewed recordings or ones older than six months, as they’re no longer linked to the random ID.

Is your voice data being used for advertising?

We’ve looked at each company’s privacy policy to see whether your smart speaker interactions are used for ads. Here’s what we’ve learned:

• Google: As their policy mentions, Google doesn’t use any video, audio, or home environment sensor data for personalized ads. However, the text from your Assistant interactions can be used for ad personalization, though luckily you can opt out.
• Amazon: Alexa uses your voice data to serve you interest-based ads—though, once again, you can go to your Alexa Privacy settings to manage your preferences. You’ll still get ads, but they won’t be as targeted.
• Apple: As expected, Apple doesn’t use Siri data for marketing or ads, nor do they sell it to third parties.

Accidental wake-ups and unwanted recordings

Smart speakers can wake up unintentionally, whether it’s due to background TV, mishearing, or random noises that sound close enough to the wake phrase.

In one test, researchers played 134 hours of TV dialogue to several models. Some devices misfired almost once per hour, and a portion of those activations lasted long enough to pick up real speech, including clips over 10 seconds.

These mistakes also don’t follow a clear pattern. The same phrase might trigger the speaker one time and fail the next, while some triggers don’t even resemble the wake word. Either way, once it activates, the device can capture audio from potentially sensitive conversations and send it to company servers.

Smart speaker hacking and connected device risks

A good rule of thumb in cybersecurity is that if something can connect to the internet, it can be hacked, and a smart speaker is no different. The fact that you can link sensitive accounts and other smart home gadgets to one makes things worse if it gets breached.

Now, Amazon and Google have tightened their review systems around Alexa “skills” and Google Assistant “actions”, but only after an FTC-published research paper showed how easy it was to sneak in malicious or policy-breaking apps.

They demonstrated a couple of ways apps could trick users:

• Voice squatting: Similarly to typosquatting, a malicious skill may use a name that’s close to the real thing, so the assistant opens the wrong app due to speech recognition errors (e.g., “call” vs “coal”).
• Voice masquerading: A skill may pretend to end the session with a message like “goodbye,” but instead keeps the session open in the background, allowing it to continue listening.

Despite the stricter app certification requirements, some attacks and malicious apps can still slip through. Here’s what you can expect.

1. Malicious post-review changes to apps

Some skills may be “clean” during review, but nothing’s stopping a developer from making malicious changes afterward. Significant updates need to be resubmitted for review before they go live, but server-side or backend changes (how the app responds or what it does once invoked) can often be made without full re-review.

2. Synthetic voice command attacks (voice cloning)

Synthetic voice attacks use AI-generated speech to issue commands that sound like a real person. If someone gets a clean voice sample, they can clone it and use it to trigger assistants that rely on voice recognition.

Even basic tools can help with this. Voice changers like Voice AI can mimic tone and speech patterns well enough to fool systems under the right conditions.

3. Prompt injection through connected services

Prompt injection targets assistants via the services you connect to, not through direct speech. If your smart speaker pulls in content from email, calendars, or notes, an attacker can hide instructions inside that content.

For example, a malicious calendar invite could contain text that nudges the assistant into taking actions you didn’t request, like turning on your boiler and switching off lights. The more services you link, the more ways you give attackers to influence how the assistant behaves.

Related: What is IoT malware and how to secure your smart home

Smart speaker privacy settings by brand

Adjusting a few smart speaker privacy settings can prevent your voice data from being used for AI training or “improving services,” or stored for months in a company database, waiting for the next leak.

Google Nest privacy controls

1. Delete voice history

Google Assistant

1. Open the Assistant activity page and sign in.
2. In the Google Assistant banner on the top-right, press More > Delete activity by.
3. Select All time and tap Delete.
4. Tap Delete again to confirm.

Gemini for Home

1. Open the Google Home app and tap your profile on the top right.
2. Go to Home settings > Privacy > Home History.
3. Alternatively, visit the Google Home History page in your browser.
4. Choose Turn off > Turn off and delete activity.
5. Press Delete, then All time (or a specific period depending on your needs).

2. Auto-delete saved activity

Google Assistant

1. Go to myactivity.google.com and sign in.
2. Select Web & App Activity.
3. Click Auto-delete > Auto-delete activity older than and select 3 months.

Gemini for Home

1. In the Google Home app, tap your profile (top-right).
2. Navigate to Home settings > Privacy > Home History.
3. Tap Settings & help > Activity.
4. Once again, you can visit Google Home History in your browser instead.
5. Press Deleting activity older than 18 months (the default).
6. Select Auto-delete activity older than, then select 3, 18, or 36 months.

3. Stop saving voice activity

Google Assistant

1. Head to the Web & App Activity page.
2. Click Saving activity.
3. Uncheck the Include voice and audio activity option.

Gemini for Home

1. Open the Google Home app > tap your profile > Home settings > Privacy > Home History.
2. Or, go directly to myactivity.google.com/product/home
3. Turn Home History off.
4. When prompted, choose Turn off and delete activity to also erase existing history (optional).

Note: Even when turned off, Google still temporarily keeps queries for up to 24 hours for service, safety, and feedback.

4. Mute microphone

• Most models (Nest Mini, Nest Audio, Nest Hub and Hub Max, Google Home, etc.): Use the physical microphone switch on the back or side of the device. Slide or toggle it to the off position. The lights will turn orange/red to confirm the microphone is muted.
• Nest Wifi Point: Use the microphone switch on the back (next to the power cord). An orange color means the mic is off.

Alexa privacy controls

1. Delete voice history

1. Open the Alexa app.
2. Tap More > Alexa Privacy.
3. Select Review Voice History and choose a date range or All History.
4. Press Delete all History to finish up.

2. Limit data use for improvement

1. From Alexa Privacy, go to Manage Your Alexa Data.
2. Scroll down to Help Improve Alexa.
3. Turn off Use Voice Recordings and Use messages to improve transcriptions.

3. Stop saving future recordings

1. In Alexa Privacy choose Manage Your Alexa Data.
2. Under Voice Recordings, tap Choose how long to save recordings.
3. Select Don’t save recordings.

4. Manage skill permissions

1. Alexa Privacy again, this time head to Manage Skill Permissions.
2. Here you can choose what data skills have access to (like address or lists).
3. Then, you can toggle permissions off for skills you don’t use.

5. Mute microphone

1. Press the microphone button on your Echo, Echo Dot, or Echo Show device.
2. If the red light is on, the mic is off.

Apple HomePod privacy controls

1. Delete Siri history

1. Open the Home app on your iPhone or iPad.
2. Tap the HomePod, then the gear icon (Settings).
3. Go to Siri History.
4. Tap Delete Siri History.

2. Turn off “Siri” or “Hey Siri”

Easy enough: simply say “Hey Siri, stop listening.” and your HomePod will do just that. Touch and hold the top of the HomePod to turn it back on.

3. Turn off Location Services

1. Open the Home app.
2. Tap the three horizontal dots (More), then Home Settings.
3. Scroll down and turn off Location Services.

Sonos smart speaker privacy controls

1. Disable Voice Control

Use the physical mic switch on the back of the speaker (completely cuts power to the mic) or tap the speech bubble icon on top (Era 100/300 and similar models).

2. Remove Google Assistant/Alexa

If you want to remove Alexa or Google Assistant from your Sonos speaker(s), just follow these steps:

1. Open the Sonos app.
2. Go to Settings > General Settings > Voice Assistants (or Settings > Services & Voice if you’re using the S1 Controller app).
3. Select the voice assistant you want to remove.
4. Choose the speaker, then tap Remove.

Smart speaker privacy tips and best practices

Here are practical steps you can take to safeguard your smart speaker’s privacy beyond adjusting app settings:

• Review household access regularly: Check who can control your speaker, view its history, or manage connected devices. Remove any users who no longer need access.
• Use the physical microphone mute: Turn off the mic with the built-in button or switch during private talks, at night, or when away from home. The device won’t listen until you reactivate it.
• Secure your home network: Update your router’s firmware, replace default passwords with strong ones, and enable WPA3 encryption if available.
• Isolate smart devices: Place your smart speaker on a separate guest or IoT network to limit its access to your main personal devices.
• Consider a router-level VPN: VPNs encrypt your network traffic to limit what your ISP can see, and prevent attackers from snooping on you. Note that a VPN won’t prevent the vendor from collecting your data if you haven’t opted out.
• Enable multi-factor authentication: Add 2FA or MFA to your linked accounts (Amazon, Google, Apple ID) for an extra security layer against unauthorized access to your voice and linked account data.
• Restrict linked permissions: Review and revoke access for third-party skills, apps, or services connected to your speaker. Limit what data they can access, such as contacts, calendar, or shopping.
• Avoid sharing sensitive details: Never speak passwords, credit card numbers, health info, or other private matters near the speaker. Even a single accidental wake-up can cause that audio to be recorded and stored.
• Think about your speaker placement: Keep them in common areas rather than bedrooms or private spaces to reduce the risk of them listening in on sensitive conversations.
• Keep everything updated: Enable automatic firmware and app updates for your speaker and router to patch security vulnerabilities as soon as possible.

Further reading: Securing your wireless router and wi-fi network

Smart speaker vulnerabilities and data leaks

While large-scale customer data breaches are relatively rare, smart speakers have been affected by several high-profile privacy incidents, technical vulnerabilities, and class-action lawsuits. Here are some notable examples:

• Google Home hidden account backdoor (2022): Researcher Matt Kunze demonstrated a method to secretly add to Google Home, giving attackers remote access, the ability to activate the mic via calls, and control over local network requests. Google resolved it and paid a $107,500 bug bounty.
• Sonos covert audio exfiltration chain (2024): NCC Group uncovered multiple flaws in Sonos One devices that let nearby attackers run code remotely, record surrounding conversations, and transmit the audio. Sonos had fixed the issues in late 2023.
• Amazon Alexa voiceprint BIPA class action (2025): An Illinois judge approved a class of about 1.2 million users who claim Amazon collected their voice biometrics through Voice ID without proper consent. The lawsuit is ongoing as of April 2026.

Is a smart speaker worth the privacy risk?

It depends on your needs. For elderly or disabled people, a smart speaker can be a great boost to accessibility. However, with companies “upgrading” to slow, chatty, hallucination-prone AI models that sometimes misunderstand or refuse tasks, many users feel like their once-useful voice assistants took a turn for the worse.

Even if they didn’t, it’s hard to ignore the glaring privacy issues. These devices are always-listening microphones that can record conversations, store voiceprints, and sometimes share data with third parties.

Sure, you can disable most of it, but you end up with a severely watered-down experience as a result. In the end, they can be worth it if you use them carefully, stick to the basics, and avoid discussing sensitive topics around them.

Smart speaker privacy FAQs

Also read:

• How to stop your smart TV from spying on you
• Comparing the privacy policy of internet giants side-by-side