How long does the call blocking SDK take to integrate?

About 10 lines of app code on each platform: register the SDK on launch, then call isSpam and lookupLabel. Native Swift and Kotlin, Flutter and React Native are all supported. iOS needs the usual Apple extension targets, which the setup script adds for you.

Do subscriber phone numbers leave the device?

Not in the clear. On iOS, lookups run through Apple Live Caller ID Lookup with private information retrieval and homomorphic encryption. On Android, lookups use k-anonymity. We never see which number a subscriber looked up, so a breach of call logs on our side is not possible.

How do partners make money with the SDK?

Sell spam protection to your subscribers as a paid feature under your own brand. Partners keep about 70% of what the feature earns. For an MVNO on thin margins, that is a new ARPU line with no data infrastructure to build.

Is the SDK white-label?

Yes. Your name appears on every blocked call and every caller label. CallerAPI is never visible to the end user.

Call blocking SDK for iOS and Android, white-label, about 10 lines of code

The CallerAPI call blocking SDK puts spam protection inside your own app, under your own brand. MVNOs and mobile security vendors sell it as a VAS to increase ARPU. Users stop answering scams and stay longer.

Get the SDK Read the docs

Application.kt

Kotlin

import com.callerapi.sdk.CallerAPI

override fun onCreate() {
    super.onCreate()
    CallerAPI.register(
        context = this,
        featureEnabled = true,
        clientKey = "<dashboard client key>",
    )
}

val spam  = CallerAPI.isSpam("+18882211161")     // true
val label = CallerAPI.lookupLabel("+18883578668") // "CallerAPI LC"

4

platforms from one package: Swift, Kotlin, Flutter and React Native.

~10

lines of app code per platform. Register on launch, then ask two questions.

0

subscriber numbers visible to us. Lookups are anonymous on iOS and on Android.

Register once. Two calls after that.

Your app asks two questions: is this spam, and who is it. The SDK does everything else.

App.swift

Swift

import CallerAPI

CallerAPI.configure(
    CallerAPIConfig(sdkKey: "<dashboard>",
                    sdkSecret: "<dashboard>"),
    featureEnabled: true)
CallerAPI.BackgroundSync.register()

let spam  = try await CallerAPI.isSpam("+18882211161")
let label = try await CallerAPI.lookupLabel("+18883578668")

What the SDK carries for you

Call screening service. Incoming calls are checked and labeled before they ring.
Background sync. Verdicts stay fresh without your app opening.
Apple extensions. Call Directory and Live Caller ID targets, added by the setup script.
Anonymous lookups. Private information retrieval on iOS, k-anonymity on Android.
Metering. Device and block counts in the dashboard, so billing needs no guesswork.

Flutter and React Native wrap the same two calls.

The breach that cannot happen

Carrier apps have leaked subscriber call logs before. This SDK is built so that class of breach is impossible on our side, because we never receive the number being checked.

On the phone

Incoming call

The OS hands the number to your app's screening extension. It never leaves the device in the clear.

iOS

Live Caller ID Lookup

Private information retrieval over homomorphic encryption. The server answers a query it cannot read. Older iPhones use Call Directory on-device.

Android

k-anonymity

The device asks about a bucket of numbers, never one. The match happens on the phone. We cannot tell which number rang.

On our side

Nothing to leak

No call log, no lookup history, no subscriber numbers. Your privacy review gets a short answer.

A feature subscribers pay for every month

Minutes and data are commodities. Spam protection is not. Put it in the plan as a paid add-on or a premium tier, under your name, and about 70% of what it earns stays with you. The data, the infrastructure and the app extensions are ours to run. The customer relationship and the margin are yours.

Licensing is a flat fee or per subscriber per month with active blocking. The dashboard reports devices and blocks, so billing needs no guesswork.

Where each subscription dollar goes

You, about 70%

CallerAPI

Your brand on every blocked call and caller label
No data team, no complaint feeds to license, no infrastructure to run
Lower churn: subscribers whose phone stops ringing with scams stay

Who ships the call blocking SDK

Companies that already have the users and were missing the feature.

MVNOs and carriers

Margins on minutes and data are thin. Spam protection is a feature subscribers pay for every month, and you keep about 70% of it. Your brand is on every blocked call. Churn drops because the phone stops ringing with scams.

Runs on the same data as the spam phone number database you may already host at the switch.

Mobile security vendors

You already sell antivirus, VPN or identity protection to millions of devices. Scam call blocking is the feature they ask for next. Add it in a sprint and charge for the tier.

CPaaS and UCaaS with an app

Your softphone already shows the caller. Now it labels spam and blocks it, with the same verdicts as the spam call blocking API on your platform.

We ship it ourselves

WarnCall, our own consumer blocking app, runs on this SDK. Every fix and every platform update lands in the package you get, because we depend on it too.

What the package includes

Native libraries for Swift and Kotlin, plus Flutter and React Native bridges
Setup scripts that add the iOS extension targets for you
Caller labels and spam verdicts on incoming calls, plus lookups from your own UI
Dashboard with device counts and block counts for billing
Junior-proof integration docs and a test number that always returns a label

Swift

Kotlin

Flutter

React Native

Call blocking SDK questions

Ship spam protection this sprint

Tell us your platforms and subscriber count. You get the package, the docs and a revenue model the same week.

Get the SDK See the MVNO stack