From time-to-time I receive "Unknown" caller on my mobile phone. I do not want to answer those calls as I do not trust the identity of a caller. I feel safer if I can see caller name or at least caller phone number.

I do realise that some businesses mask their identity, so they do not receive many return calls from potentially angry customers. However, I don't care.

For emails, we have effective spam-catching filters that often sit on the recipient side. For mobile phone calls there is no effective similar system available (for example registering with a government backed Do-Not-Call web sites, like this one in UK does not help me). I feel a more robust system will block/mute/ ignore/choose-your-action such calls on the receiving end.

Problem: Windows phone OS does not expose caller API, possibly due to security concern. Sources: SO question, forum post, not implemented feature request.

Questions: Is there any valid security concern that forces OS vendors to block access to the caller API for the developers? Is there any way to stay safe and secure, but also allow caller API be available for developers (so they can develop legit blocking apps)?

  • Calling TPS effective is a bit of a joke... And the whole new we'll force caller ID from call centers means my phone nolonger blocks the b#"%&$#~, withheld and unknown numbers being sent straight to answer phone was real nice for a while.
    – ewanm89
    Commented Jun 22, 2016 at 20:05

1 Answer 1


In general, OS vendors implement what network provider wish to see, and network providers are very wary about interfacing the bits which do the actual phoning, with user-provided code. They don't want customers refusing to pay their bills and defending themselves by saying that they did not pass the calls, but some virus on their phone did. Such a defence would have some non-negligible chance of success in court. There's big money at stake here, so caution is applied. "Caution" meaning here keeping as much internal separation as is possible. Not making the caller API available to application seems to participate to this general separation principle.

  • In other words, it's security of the network providers to continue to fleece customers. Yeah, that is always a good definition of security.
    – ewanm89
    Commented Jun 22, 2016 at 20:07

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .