Call Lookup

Identifies publicly available information (such as name, address, etc.) based on a phone number. This is especially useful for recognizing incoming calls in systems such as:

• Telephony systems

• CRMs

• Helpdesk systems

Authentication with API Key

To access the API, an API key is required.

1

Obtaining the API Key

The API key is provided after successful onboarding.

2

Using the API Key in the request

The API key must be included in the header of each request.

Example:

curl --location 'https://api.multisource.ch/v2/search/calllookup?number=[phone]' \
--header 'Auth-Key: <API-KEY>'

API Endpoint

get

https://api.multisource.ch/v2https://api.multisource.chhttps://apitep.multisource.ch

/Search/CallLookup

Authorizations

auth-key

auth-keystringRequired

API Key required for authorized endpoints

Query parameters

numberstringOptional

outputFormatintegerOptionalDefault: 1

Responses

200

OK

text/plainapplication/jsontext/json

hitCountinteger · int32Optional

resultCountinteger · int32Optional

get

/Search/CallLookup

HTTPcURLJavaScriptPython

GET /v2/Search/CallLookup HTTP/1.1
Host: api.multisource.ch
auth-key: YOUR_API_KEY
Accept: */*

200

OK

{
  "hitCount": 1,
  "resultCount": 1,
  "data": [
    {
      "dwhId": "text",
      "companyname": "text",
      "firstname": "text",
      "name": "text",
      "street": "text",
      "houseNumber": "text",
      "zip": "text",
      "location": "text",
      "phoneNumbers": [
        "text"
      ],
      "mobileNumbers": [
        "text"
      ]
    }
  ]
}

Parameters

Parameter	Type	Description	Example
number	string	The phone number in local format (without country code) or in E.164 format (with +)	0791234567 [phone]
outputFormat	integer	Format of the returned phone number: 1 = Local format (without country code) 2 = E.164 (with + and country code)	1 = 0791234567 2 = [phone]

Response Fields

Root-Level Fields

Field	Type	Description	Example
hitCount	integer	Total number of matches in the database for the requested phone number	1
resultCount	integer	Number of entries actually returned in the data array	1
data	array	Array containing the found directory entries	see Entry Fields below

Entry Fields

Field	Type	Description	Example
dwhId	string	Unique ID of the entry	ABC123456789
companyname	string	Company name for business entries	Swisscom Directories AG
firstname	string	First name for private individuals	Lara
name	string	Last name for private individuals	Graf
street	string	Street name	Förrlibuckstrasse
houseNumber	string	House number	62
zip	string	Postal code	8005
location	string	City/Town name	Zürich
phoneNumbers	array	Array with one or more landline numbers	[ “*0800 123 456", "*058 123 45 67" ]
mobileNumbers	array	Array with one or more mobile numbers	[ “*079 123 45 67" ]

Requirements for Successful Results

The provided phone number must be listed in our public directories (local.ch or search.ch) and enabled for reverse lookup.

Notes

Phone Numbers as Arrays

• phoneNumbers and mobileNumbers are always arrays, even with only one number

• Empty arrays [] indicate that no numbers of this type are available

Handling Multiple Entries

A phone number can have multiple entries (e.g., multiple people in one household or different departments of a company). When multiple entries are returned (resultCount > 1), we recommend the following display logic for integration:

Option 1: Display First Entry

The first entry in the data array is typically the main entry and is suitable for simple display in telephone systems.

Option 2: Offer All Entries

For advanced integrations, all returned entries can be displayed in a dropdown list or as selectable options.

Example: Output with Multiple Entries

{
  "id": "123",
  "status": 200,
  "info": [],
  "result": {
    "hitCount": 2,
    "resultCount": 2,
    "data": [
      {
        "dwhId": "ABC1234567890",
        "companyname": "Swisscom Directories AG",
        "firstname": "",
        "name": "",
        "street": "Förrlibuckstrasse",
        "houseNumber": "62",
        "zip": "8005",
        "location": "Zürich",
        "phoneNumbers": [],
        "mobileNumbers": [
          "*079 123 45 67"
        ]
      },
      {
        "dwhId": "CBA0987654321",
        "companyname": "",
        "firstname": "Lara",
        "name": "Graf",
        "street": "Förrlibuckstrasse",
        "houseNumber": "62",
        "zip": "8005",
        "location": "Zürich",
        "phoneNumbers": [],
        "mobileNumbers": [
          "*079 123 45 67"
        ]
      }
    ]
  }
}