PrefixBlocker

Siesta Soft S.L.

In-app purchases

About this app

PrefixBlocker stops unwanted and spam calls with rules you decide - by country prefix, by numbers that start with a specific sequence, by saved contacts and groups. Privacy comes first: no account, no cloud, no data collection. Everything stays on your phone.

Most standard call filters cannot block entire number prefixes. PrefixBlocker can. Block an entire country code, a specific area, or patterns like +12 345* in a single tap.

WHY PREFIXBLOCKER
- Block by prefix: entire country codes or numbers that start with a certain sequence, which normal filters miss.
- Privacy by design: no numbers collected, no shared spam database, nothing to leak or sell.
- Your rules, not an algorithm: you decide who to block, not a list managed by someone else.
- Works offline: no connection needed to block a call.
- One-time unlock, no subscription.

FEATURES
- Prefix filter with two modes: Block list (block what you add) or Allow only (accept only what you add, block the rest).
- Blocking by country or by the start of a number, guided by a built-in list of countries.
- Contacts and groups: allow your entire address book, block selected contacts, allow only the contacts and groups you choose, or apply your prefix rules to contacts too. Contacts are optional and resolved locally - they never leave your phone.
- Group schedule: block a group only on the days and time ranges you choose.
- Anonymous calls: separately block calls with hidden or unavailable numbers.
- Transparent activity log: see every blocked call and the exact rule that caused it.
- Statistics: today, this month and all time, plus a 7-day chart and your most blocked prefixes.
- Optional system notifications for blocked calls, which you can turn on in Settings.
- Light and dark theme.

HOW IT WORKS
1. Turn on the prefix filter and choose a mode.
2. Add the countries, prefixes or numbers you want to block or allow.
3. Optionally choose which contacts and groups to block or allow, and manage anonymous calls.
PrefixBlocker applies a clear, predictable order of precedence to every incoming call, so the behavior is always transparent.

PRIVACY
PrefixBlocker does not create an account, does not use any server, and does not collect or upload your phone numbers or contacts. If we do not collect anything, there is nothing to lose, sell or leak. No ads, no tracking.

PERMISSIONS
- Call screening role: required to decide whether to block an incoming call.
- Contacts (optional): requested only if you enable an address book filter to block or allow selected contacts and groups; used locally to identify callers.
- Notifications (optional): requested only if you turn on blocked-call notifications.
PrefixBlocker is not a dialer and does not read your call log or messages.

PRICING
Try it free: the first 10 blocked calls are included. A single one-time purchase unlocks unlimited blocking - no subscription, ever.

Ratings and reviews

The app is legit and already paid for itself in peace and quiet. You get 10 blocks for free and then it's a very small one-time fee. Not a bad price for the ability to block all toll-free calls. I went with this app because it's lightweight and I didn't want to pay a monthly fee like other apps try to charge.

Does exactly as advertised ! No ads or annoyances. Looked at other call blockers and those were subscription based and expensive. I am happy with this product and my ability to keep scammers out of my hair ! P.S. Thank you for coding this effective app !!!!

Reached out about the possibility of adding area codes to the prefixes that use +1 due to multiple countries using it, and within a day they emailed me back and pushed out an update that included it! Their response was super quick and the turnaround on it was amazing, immediately went and purchased the full version. Also a special shout-out for the app being a one-time purchase (for a low price) instead of a subscription. in this day and age, it means a lot. App does exactly what it describes!

What’s new

New: a dedicated block for Spanish commercial calls, which use the new 400* numbering introduced in Spain since October 2026 (even when they show up without a prefix). You can find it in Prefixes if you use a Spanish SIM, or with "Manage" in Activity if you have already received calls from those numbers.