Number Portability Lookup HLR HTTP API

We also have plug-and-play scripts to integrate carrier lookups into your Asterisk dialplan - no coding required!

API Details - v3.32

Introduction to the API

Our API (Application Programming Interface) is designed to make it easy to integrate our number portability lookup service into your own application, with the minimum amount of additional programming.

Connectivity to the service

Connectivity to the API is provided by via HTTPS POST to the following URL:

https://api.numberportabilitylookup.com/npl

There is a maximum of 100 numbers per request, and a maximum of five concurrent connections per account unless agreed otherwise.

Note that realtime SS7/MAP or other lookups take time to process, so a large batch of numbers may take a while to process and return, however, responses will be streamed over the HTTP response as they become available.

Important Note / Feb 2025: While alternative API endpoints have been available in the past, these should be considered deprecated at this time. Please ensure all traffic is using the api.numberportabilitylookup.com/npl endpoint to avoid possible future service interruptions if the older API endpoints are decommissioned.

Performing an HLR Lookup

In order to perform an HLR query on one or more mobile numbers, pass the following parameters:

user	Your account username
pass	Your account password
msisdn	The number(s) to look up in E.164 format. Separate multiple numbers with commas
format	Use format=json for the most comprehensive response. If omitted, the system will revert to a legacy CSV format with basic data points for compatibility with older API clients. New integrations should always use the 'json' format.
msc	Pass msc=1 to request serving MSC address (if feature is enabled on your account), otherwise omit. Note: Querying the serving MSC address is increasingly blocked due to its use in SS7 messaging fraud. Please contact us if you have a legitimate need for this data field and we can confirm availability for the networks you need.

Example Request:

https://api.numberportabilitylookup.com/npl?user=bob&pass=123&msisdn=447788450450,447810701702&format=json

Number Formatting

Numbers should be specified in the standard E.164 international format. i.e. Country Code, and National Significant Number without National prefixing if any exist. The leading '+' symbol is not required by our service.

Example: UK 07788 450 450 -> 447788450450
Example: USA 704 451 8989 -> 17044518989
Example: AUS 0449100123 -> 61449100123

If you need help on how to format a number for a specific country, please [ Contact us ].

Errors which could prevent your HLR lookup from running:

If there is a problem that prevents our system from starting to process your HLR lookup, your account balance will not be charged for the API call, and you'll receive a FAIL code:

FAIL Authentication required	The user and pass fields are required. See above.
FAIL Invalid password	The supplied user and pass were not correct.
FAIL No numbers	You didn't pass any numbers to lookup. The msisdn field is required.
FAIL Request too long	You tried to lookup more than 100 numbers.
FAIL Insufficient credit	Your account balance is too low. Please add funds.
FAIL Connection limit	You have more simultaneous connections than allowed on your account (default 5).
FAIL Daily limit	You have exceeded your soft daily limit. You can change this in your online account.
FAIL Unsupported region	You attempted to lookup a number in a country other than those allowed on your account.
FAIL Account locked	There is a problem with your account. Contact support.
FAIL System Unavailable	The service is undergoing maintenance. Please try later.

Example Responses

If the API response does not begin with the string FAIL, you should attempt to parse it as JSON per the structure below:


Example JSON Format Response

You'll receive a JSON array containing a data block for each MSISDN queried.

[
	{
		"countrycode":"44",
		"countryiso":"GB",
		"countryname":"United Kingdom",
		"errorcode":0,
		"errortext":"OK",
		"imsi":"234158341040126",
		"localformat":"07788 450450",
		"mcc":"234",
		"mnc":"15",
		"msc":"44778",
		"msisdn":"447788450450",
		"operatorname":"Vodafone",
		"originalmcc":"234",
		"originalmnc":"15",
		"originaloperatorname":"Vodafone",
		"plmn":"23415",
		"ported":false,
		"reachable":true,
		"transactioncost":1.20,
		"validnumber":true
	}
]




Example Legacy CSV Format Response

If you did not pass format=json you'll receive our legacy CSV API response as shown below:

QUERYOK
447788450450 23415,234158341040126,44778
ENDBATCH

The fields provided are: number mcc+mnc,imsi,msc
No other data points are available when using this format. We recommend using format=json for all new integrations.

Description of data fields contained in response

GSM / Worldwide HLR Query Response fields:

countrycode	Country code of number's home country
countryiso	ISO 3166 country code of number's home country
countryname	Name of number's home country
errorcode	Error number if any error, otherwise 0
errortext	Description of the error code (otherwise "OK")
imsi	International mobile subscriber ID of the subscriber (see note below)
landline	Whether the number is a landline number (true or false)
lrn	Location routing number for PSTN calls (NANP)
localformat	Phone number formatted as it would be written in its home country
mobile	Whether the number is a mobile number (true or false)
mcc	GSM Mobile country code of the home network
mnc	GSM Mobile network code of the home network
msc	Mobile switching centre currently serving this number (if supported and enabled)
msisdn	Mobile number to which this query pertains
numbertype	Type of number ("MOBILE","LANDLINE","VOIP", or "TOLLFREE")
ocn	Operating carrier number for NANP numbers
operatorname	Name of the home network operator
originalmcc	MCC of the original operator (if ported)
originalmnc	MNC of the original operator (if ported)
originalcarrier	Name of the original carrier (if ported)
originaloperatorname	Name of the original operator (if ported)
plmn	Public land mobile network code of home network (mcc+mnc)
ported	Whether the number has been ported (true or false)
reachable	Whether the number is in coverage and reachable (true, false, or "undetermined") META
spid	Service Profile ID
timezone	Timezone where the number is registered
transactioncost	Cost of this lookup in credits (eg 1.00)
userbalance	Remaining balance in user account after transactioncost was deducted
validnumber	Whether the number is a valid subscriber (true, false, or "undetermined") META

IMSI field:

The last digits of the IMSI are typically masked or converted to zeros to prevent messaging fraud. If you have a legitimate need to query the full IMSI please contact us with you use case and required destination networks and we can check for availability.

Calculated META fields:

Note that reachable and validnumber fields are not data retrieved from the mobile networks via the HLR subsystem, but are calculated based on a set of conditions in the IMSI, Errorcode, and MSC responses to make an informed decision as to the current status of the number.

The "reachable" field:

The reachable field is a convenience flag computed by our API to indicate whether there is a good chance of a call or text reaching the subscriber's equipment at this moment. If a realtime HLR lookup returned a valid response with no HLR error code, then the number is considered to be "reachable". Due to availability of network coverage and other technical considerations, this is not a guarantee that any call or text will immediately reach the subscriber, if at all.

If an error response is received, including temporary errors (such as "Absent Subscriber", which indicates the handset is offline) then reachable will show false. This is a realtime determination, and may change in a matter of hours or minutes; for example, a handset may be switched off, or out of coverage.

In the event of an HLR exception, or if the destination number is not in a realtime HLR region (for example, NANP), the API will return "undetermined" to indicate that the realtime reachability of this number cannot be calculated at present.

The "validnumber" field:

The validnumber field is a convenience flag computed on our system to indicate whether the MSISDN is a valid number assigned to an active subscriber (as opposed to an unassigned, or deactivated number). The validnumber flag will show true if a realtime HLR response returns either no error, or a temporary error which indicates the number is known to the operator, such as "Absent Subscriber".

This field does not offer any opinion as to the reachability of a number, only that it appears to be a valid number and is likely to be assigned to an active subscriber of the mobile network operator.

In the event that an HLR exception occurs or the number is not in a realtime HLR region (such as NANP numbers), the API will return "undetermined" to indicate that the validity of the number cannot be calculated at present.

Undetermined Status

In the event that we cannot calculate or provide these metadata fields, the API will return "undetermined". This does not indicate the query has failed or that there is any technical problem. For example, NANP numbers will show "undetermined" due to the lookup method used, which simply does not support these feature.

North American Number Lookup Response fields:

msisdn	The number queried
ocn	The carrier's OCN Code
carrier	The carrier's name
numbertype	The type of number (eg "MOBILE", "PCS", "WIRELESS") for mobile, ("LANDLINE", "CLEC", or "RBOC") for landline

List of possible error codes

The following is a list of response codes that can be returned in the errorcode and errortext fields:

Code	Message	Description / Possible Cause
0	Lookup Complete	HLR returned valid SM routing data in response to SRI query
1	Unknown Subscriber	There is no directory number for the mobile subscriber (GSM 09.02)
5	Unidentified Subscriber	MAP response from MSC/VLR returned a negative response (GSM 03.07)
6	Absent Subscriber (SM)	Subscriber record is marked as unavailable as there was no paging response from the handset. May be switched off, in low coverage, or subject to roaming restrictions.
7	Unknown Equipment	Subscriber's mobile device has not been recognised (EIR)
8	Roaming Not Allowed	Subscriber is roaming on another network where roaming agreements may not be fully in place
9	Illegal Subscriber	Mobile station failed authentication
11	Teleservice Not Provisioned	The recipient mobile station has no SMS subscription (GSM 09.02)
12	Illegal Equipment	Mobile station was black-listed
13	Call Barred	Rejected due to barring of the mobile station (see GSM 09.02, description of the Barring supplementary service, GSM 02.04 and 03.11, and description of Operator Determined Barring, GSM 02.41 and 03.15).
21	Facility not Supported	SMS is not provisioned in the VPLMN (GSM 09.02).
27	Absent Subscriber	VLR has no IMSI record, or if the record is marked "Subscriber Data Not Confirmed by HLR" (GSM 03.07)
31	Subscriber Busy for MT SMS	Rejected because of congestion encountered at the remote MSC
32	SM Delivery Failure	SM Delivery Failure has occurred
33	Message Waiting List Full	Rejected because the mobile station is out of storage
34	Partner System Failure	The network partner encountered an error performing this operation
35	Data Missing or Unroutable	No routing exists to reach this prefix at the current time
36	Lookup Failure	Network or protocol failure, or invalid numbering plan prefix
38	Rejected	HLR subsystem rejected number - non-mobile or unsupported carrier

Checking your account balance

To query the balance of your account via the API pass the following parameters:

user	Your account username
pass	Your account password
query	balance

Example Request:

https://api.numberportabilitylookup.com/npl?user=bob&pass=123&query=balance

The response will give your remaining account balance as the number of lookups that can be performed before your account is depleted.

Example Response

HTTP/1.1 200 OK

45999564

Note: When performing a number lookup, the response will contain a "userbalance" parameter which provides this information without needing to run a separate query=balance API call. In many circumstances, this may be more efficient.

Multiple Simultaneous Connections

By default your account allows a maximum of 5 simultaneous HTTP connections to our API from the same user at the same time. Any additional connections will be rejected with ERR RATE_LIMIT_EXCEEDED.

We recommend that if you have a high volume of traffic, you send two or more queries (up to ten) per HTTP call by separating MSISDN numbers by commas. This increases the efficiency of the traffic as you are not establishing a connection and negotiating an HTTPS handshake for every individual number, but spreading that overhead across multiple lookups.

In the event that you have a high volume of traffic and five threads is not sufficient please contact us.

Coverage Check API

Our coverage check API provides information on networks that are currently within our reach (close to 100% globally), the type of connection that will be used for a query, and the response you can expect for each network in our coverage.


Coverage API: Country List

https://api.numberportabilitylookup.com/coverage/countries.json

Provides a list of countries which may be supported.


iso2	International Standards Organization ISO-2 country code
countryname	Country name
fixed_networks	Number of fixed-line networks supported
mobile_networks	Number of mobile networks supported
sri_coverage	Number of mobile networks covered by SRI with live subscriber status
live_coverage	Number of networks by live connections without subscriber status
feed_coverage	Number of networks covered by carrier data feeds
total_coverage	Total number of networks covered in this country
network_list	API URL of the network list for this country

Coverage API: Network List

https://api.numberportabilitylookup.com/coverage/countries/{country}/networks.json

Provides a list of supported networks in the specified country.


iso2	international Standards Organization ISO-2 country code
countryname	Country name
lastupdate	When the coverage data was last updated (usually hourly)
mcc	Mobile country code of the operator (SIM IMSI Prefix)
mnc	Mobile network code of the operator (SIM IMSI Prefix)
netname	Name of the operator
nettype	Type of network operator (mobile/fixedline)
coverage	Is the network covered by our service (true or false)
connectiontype	How the lookup is performed ("sri", "portability", or "datafeed")
subscriberstatus	Is live subscriber/handset status available (true or false)
portstatus	Type of number port information: ("live" or "datafeed")

For Further Assistance

For further assistance with the API, please [ Contact us ]

For an instant-setup account to try our API - [ click here ]

Usage of this API implies agreement with our terms and conditions for use [ View Terms]