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Open Source App Blockers for Android (2026): The Honest List

Open source app blockers for Android in 2026: which ones have a public repo, a real licence and recent releases, where to install them, and their limits.

By Engineer Foodie Desk ✓ Sources checked Oct 28, 2026

9 min read

Repos, licences and release dates checked Oct 28, 2026 on each app’s F-Droid page and its GitHub or Codeberg repository; F-Droid’s rules checked the same day on its Inclusion Policy. Every source is listed at the bottom. No affiliate links on this page (how we work).

Short answer: yes, there are real open source app blockers for Android, and six of them shipped a release in the last five weeks. Curbox, DetoxDroid, TimeLimit, Zenwell, nfcGuard and PlugBrain all have a public repo, a GPL or MIT licence, and a fresh build on F-Droid (all checked Oct 28, 2026). They block different ways: website and Reels blocking, grayscale and doomscroll breaks, parent-style time limits, math puzzles, even a physical NFC tag across the room.

The honest catch is the same for all of them, and for every other blocker too: on your own phone, you’re the admin. More on that below.

Quick answer

  • Want the most features: Curbox. Apps, websites, Reels and Shorts, tamper protection, and a long list of unlock rules. GPL-3.0-or-later.
  • Want your phone boring by default: DetoxDroid. Grayscale, doomscroll breaks, waits and locks. GPL-3.0-only.
  • Setting limits for a kid, or across devices: TimeLimit. Categories, schedules, parent and child users. GPL-3.0-only.
  • Want unlocking to take real effort: nfcGuard. Unlocking means walking to an NFC tag. MIT.
  • Want a small, simple one: Zenwell or PlugBrain. Both put a challenge between you and the app.
  • Open source isn’t a must? See Best app blocker for Android.

The list: licence, source and last release

AppLicenceSourceLast release
CurboxGPL-3.0-or-laterGitHubOct 18, 2026
DetoxDroidGPL-3.0-onlyGitHubOct 27, 2026
TimeLimitGPL-3.0-onlyCodebergOct 3, 2026
ZenwellGPL-3.0-or-laterGitHubOct 25, 2026
nfcGuardMITGitHubOct 22, 2026
PlugBrainGPL-3.0-onlyGitHubOct 27, 2026

“Last release” is the date the current suggested version was added on each app’s F-Droid page, verified Oct 28, 2026. GitHub release dates can be a few days earlier and are noted per app. F-Droid doesn’t show install counts, so there are none here. None of the six F-Droid pages listed an anti-feature when checked.

Why F-Droid matters here: its Inclusion Policy says every app must be FLOSS, that “every effort is made to verify that this is the case, both by visual inspection of the source and by building the application from the published source”, and that proprietary tracking and ad SDKs “are strictly forbidden” (verified Oct 28, 2026). For an app that asks for Accessibility access to your whole phone, that’s a meaningful filter.

Curbox

What it is: “a free and open source app blocker and screen time tracker”, formerly Digipaws (F-Droid, verified Oct 28, 2026). The old github.com/nethical6/curbox URL now redirects to curbox-app/curbox-android. What it blocks: apps, websites, and parts of sites (“block just one part of a site, like m.youtube.com/shorts”), plus Instagram Reels and YouTube Shorts. It can also hide parts of an app’s screen, like the YouTube home feed. How hard to give in: you choose. Options include Strict Blockade, timed unlocks, QR or barcode unlock, sentence retyping, unlock limits, NFC unlock and adaptive math. “Tamper Protection” aims to “make it difficult to uninstall Curbox or turn off its blocking service”, and a “Settings Change Delay” makes weaker rule changes wait. Release: version 6 on F-Droid, added Oct 18, 2026 (GitHub release “6”, Oct 15, 2026). The catch: that’s a lot of switches. Budget a setup evening.

DetoxDroid

What it is: “Grayscale, doomscrolling breaker, app blocker: a boring phone by default” (F-Droid, verified Oct 28, 2026). Protection is on by default, and “you pause it on purpose”. What it blocks: groups of apps and websites with schedules and time budgets. A group can turn gray, make you wait, break a long scroll, or lock. Apps can be “deactivated outright, launcher icon and notifications included”. It counts videos on Reels, Shorts and TikTok. Websites work in “Chrome, Firefox and most browsers built on them”, but “Links that open inside another app are not covered.” How hard to give in: an “Emergency Brake” runs every group at its strictest, and “Ending early takes a ten-minute wait”. A “Commitment Password” can lock groups; the page suggests you “hand it to someone who won’t give it back the second you ask”. Release: 3.0.1 on F-Droid, added Oct 27, 2026 (GitHub v3.0.1, Oct 22, 2026). The catch: true grayscale needs the WRITE_SECURE_SETTINGS permission, granted via adb, Shizuku or root. Without it, you get an overlay that the developer calls “not true grayscale”.

TimeLimit

What it is: “Flexibly limit the usage duration” (F-Droid, verified Oct 28, 2026). Built around parent and child users, with multi-device support. What it blocks: apps grouped into categories, with allowed times per category and time limits per day or across several days (“2 hours per week end day, but in total only 3 hours”). How it works: usage-stats access to detect the current app, device admin “to detect an uninstallation of TimeLimit”, notification access, an accessibility service and draw-over-other-apps, per its page. Release: 7.8.0 on F-Droid, added Oct 3, 2026 (Codeberg tag release-7.8.0). The catch: “If a parent was chosen as user, then there are no restrictions”, so it’s built for someone else’s phone more than your own. “Some features cost money if you don’t use your own server”: 1 € a month or 10 € a year in Germany, per the same page. It also admits it “does not work good at some smartphone brands (mostly Huawei and Wiko)”.

Zenwell

What it is: “Block distracting apps and reduce screen time” (F-Droid, verified Oct 28, 2026). What it blocks: the apps you choose, on schedules and weekdays you set. How hard to give in: Strict Block, a countdown timer, a breathing timer, math problems, or typing a custom message. It has “No Internet permission” and uses an Accessibility Service to watch for blocked apps. Release: 1.7 on F-Droid, added Oct 25, 2026 (GitHub v1.7, Oct 22, 2026). The catch: the developer says it’s “in active development and various bugs are expected”.

nfcGuard

What it is: “Block distracting apps with NFC tags” (F-Droid, verified Oct 28, 2026). You put a cheap NFC sticker “somewhere inconvenient”, and “Unlocking means getting up, or deleting the app.” What it blocks: chosen apps (block mode) or everything except essentials (allow mode), with per-day schedules and timed unlocks “capped by a limit you set in advance”. There’s an emergency reset “with a configurable cooldown”. Privacy: “Fully offline: no ads, no tracking, no accounts”. Its accessibility service is optional and “declared so that it cannot retrieve window content”. Release: 1.3.2 on F-Droid, added Oct 22, 2026 (GitHub v1.3.2, Oct 4, 2026). The catch: you need a phone with NFC and an NTAG sticker. The page is honest about the other exit: you can still delete the app.

PlugBrain

What it is: “PlugBrain blocks apps and uses math challenges to reduce screen time” (F-Droid, verified Oct 28, 2026). How it works: it blocks chosen apps at scheduled intervals. To get back in, you solve a math challenge, and “the more frequently you use the apps, the harder the challenges become, but the longer you stay away, the easier they get.” “No ads”, “No internet required.” Release: 1.6.0 on F-Droid, added Oct 27, 2026 (GitHub v1.6.0, Oct 23, 2026). The catch: it’s the simplest app here. If you’re good at mental math, it’s a speed bump, not a wall.

The trade-off: you’re the admin

Every blocker on this list runs on a phone you own. That means you can revoke the Accessibility permission or uninstall the app; tamper protection only makes that slower. Open source doesn’t change this. nfcGuard’s own page says your exits are “getting up, or deleting the app.”

The developers’ answer is friction you set up while calm: DetoxDroid’s ten-minute brake, Curbox’s settings delay, PlugBrain’s math, nfcGuard’s sticker in another room. Friction beats small urges. It loses to big ones, because you hold every key. For why that happens, see Why app blockers don’t work.

The other fix is handing the key to someone else. DetoxDroid’s Commitment Password does that if you give the password away. A closed-source app built around it is FriendLock, Android only, where a friend approves each unlock or reads you a code. It isn’t open source, so it’s not in the table, and its Google Play listing calls it “a commitment device, not an unbreakable lock”, since the phone’s owner can still bypass it (listing checked Oct 24, 2026). More on the idea: Commitment device.

Disclosure: the team behind this site has a stake in FriendLock.

When a closed-source blocker fits better

Open source is the right call if you care most about seeing the code, offline use, and no tracking SDKs. A closed-source app can fit better if you want:

  • iPhone or desktop too. None of the six F-Droid pages mentions iOS.
  • One-tap setup instead of adb or Shizuku steps for extras like DetoxDroid’s true grayscale.
  • A hardware lock like Brick. See Brick alternatives.

The full field, priced and dated, is in Best app blocker for Android. If the real issue is the feed, How to stop doomscrolling is the practical starting point.

Here’s what I’d do

Most people: Curbox if websites and Shorts are the problem, DetoxDroid if you want the whole phone duller. Block your top two apps for a week, then add more.

Willpower already lost the first round: nfcGuard, with the sticker in another room, or DetoxDroid with the password given to a friend.

Parents: TimeLimit. It’s built for parent and child profiles across devices.

Just curious: PlugBrain or Zenwell. Small and offline.

FAQ

Is there an open source app blocker for Android? Yes, Curbox, DetoxDroid, TimeLimit, Zenwell, nfcGuard and PlugBrain are all on F-Droid with public source code under GPL or MIT licences, as of Oct 28, 2026.

Are F-Droid app blockers safe? F-Droid says it requires FLOSS apps, builds them from the published source, and forbids proprietary tracking and ad SDKs, but every blocker still needs broad permissions like Accessibility, so read what each one asks for.

Can an open source app blocker be bypassed? Yes, the phone’s owner can revoke permissions or uninstall any of them, so they work through friction like waits, puzzles, NFC tags or a password someone else holds.

Sources

  1. F-Droid, Curbox (description, licence, version 6 added Oct 18, 2026): https://f-droid.org/en/packages/neth.iecal.curbox/ (verified 2026-10-28)
  2. GitHub, curbox-app/curbox-android (GPL-3.0, release 6): https://github.com/curbox-app/curbox-android (verified 2026-10-28)
  3. F-Droid, DetoxDroid (description, licence, 3.0.1 added Oct 27, 2026): https://f-droid.org/en/packages/com.flx_apps.digitaldetox/ (verified 2026-10-28)
  4. GitHub, flxapps/DetoxDroid (releases): https://github.com/flxapps/DetoxDroid/releases (verified 2026-10-28)
  5. F-Droid, TimeLimit.io (description, permissions, fees, 7.8.0 added Oct 3, 2026): https://f-droid.org/en/packages/io.timelimit.android.aosp.direct/ (verified 2026-10-28)
  6. Codeberg, timelimit/timelimit-android: https://codeberg.org/timelimit/timelimit-android (verified 2026-10-28)
  7. F-Droid, Zenwell (1.7 added Oct 25, 2026): https://f-droid.org/en/packages/com.sarangem.zenwell/ (verified 2026-10-28)
  8. GitHub, sarangem/zenwell: https://github.com/sarangem/zenwell (verified 2026-10-28)
  9. F-Droid, nfcGuard (1.3.2 added Oct 22, 2026): https://f-droid.org/en/packages/com.andebugulin.nfcguard/ (verified 2026-10-28)
  10. GitHub, Andebugulin/nfcGuard: https://github.com/Andebugulin/nfcGuard (verified 2026-10-28)
  11. F-Droid, PlugBrain (1.6.0 added Oct 27, 2026): https://f-droid.org/en/packages/app.plugbrain.android/ (verified 2026-10-28)
  12. GitHub, msbelaid/PlugBrain: https://github.com/msbelaid/PlugBrain (verified 2026-10-28)
  13. F-Droid, Inclusion Policy: https://f-droid.org/en/docs/Inclusion_Policy/ (verified 2026-10-28)

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