Number lookup API vs legacy Sinch number lookup service

Charlene_Kwong — Tue, 29 Sep 2026 09:45:38 GMT

1. Does Number Lookup V2 work in the same way as legacy Sinch Number Lookup services?

No. Older Number Lookup services typically use Home Location Register (HLR) Lookup as the data source. Sinch’s first release of Number Lookup is based on data derived from National Regulators. This means that the results and how those results have been derived cannot be exploited by use-cases in the same way.

2. What is the difference between Number lookup API and HLR Lookup?

HLR Lookup is usually a live-lookup into a Mobile Operators subscriber database. However, some suppliers of this service use a cached lookup to save money. A valid response to a Telephone Number request from a HLR Lookup usually means a Telephone Number is active on the mobile operators network. The problem with this approach is that it exposes the mobile operator to personal data-loss, since operators never intended to provide access to such information. It is quite difficult for operators to removed access to such a service, but they have found ways to limit access as well as obfuscate any information provided.

This has led to significant changes in availability and accuracy of information from HLR Lookup. For instance, a HLR Lookup, if available, will typically only provide intelligence that a Number does belong to that operator, but cannot be relied upon to be live in the network or located in particular part of the global cellular network.

Sinch Number Lookup provides a more consistent set of results since it is based on regulator data. When a response is returned, it returns information about how the national regulator has assigned a number to an operator. This does not mean it is active, but that the number is available for use by an operator.

3. Will Number Lookup API meet my needs?

HLR Lookup may have previously supported multiple use-cases:

Message routing, with Port-correction
- Special permission is now required by Mobile Network Operators (MNOs) to perform this function. This use-case is no longer supported. However, in North America, Sinch Number Lookup is port corrected and can be used for routing. Sinch may add port-corrected results globally in the future.

List Cleaning for “active numbers”
- HLR Lookup may have supported this use-case several years ago, but changes in the mobile operator have reduced the efficacy for such a use-case. This is no longer supported. However, Sinch Number Lookup will help you understand if a number is properly formatted and of a line-type you might expect for a customer engagement. It is important to remember that any customer list you have must comply with Data Protection laws and if it does, then the relevance of an ‘active number’ service is diminished.

Subscriber Location
- HLR Lookup would previously return the network address, country location and roaming country of a mobile subscriber. Since 2018, this is no longer the case, since location is a sensitive subscriber attribute. All operators have made significant efforts to block access to this information.

4. Will all the missing features in the legacy API be replaced?

No. Sinch is building a Number Lookup product and roadmap that aligns robustly with global data protection regulations. However, Mobile Operators are releasing new capabilities that such new data items (such as location), but doing so with a consent mechanism built in. Sinch will be introducing these services as and when they become available from mobile operators.

article Number lookup API vs legacy Sinch number lookup service in Number Lookup API

Number lookup API vs legacy Sinch number lookup service

1. Does Number Lookup V2 work in the same way as legacy Sinch Number Lookup services?

2. What is the difference between Number lookup API and HLR Lookup?

3. Will Number Lookup API meet my needs?

4. Will all the missing features in the legacy API be replaced?