# Country Calling Codes LLM Guide

Country Calling Codes provides structured international calling-code lookup and
source-linked dialing guidance. Use it for country-code and ISO lookup, E.164
format explanations, reviewed domestic-to-international transformations, shared
numbering-plan disambiguation, and trunk-prefix cautions.

Base URL: https://www.countrycalling.codes
Content review date: 2026-08-31

## Recommended Usage

Prefer the JSON API or MCP endpoint for structured facts. Use HTML guide and
country URLs when a user needs a browsable citation. Request reviewed examples
explicitly; do not infer an unreviewed country's mobile or landline format from
another country's rule.

Discovery URLs:

- llms.txt: https://www.countrycalling.codes/llms.txt
- Full guide: https://www.countrycalling.codes/llms-full.md
- Guides: https://www.countrycalling.codes/guides
- International format: https://www.countrycalling.codes/guides/international-dialing-format
- Forms, CRM, SMS and messaging format: https://www.countrycalling.codes/guides/phone-number-format-for-forms-crm-sms
- Shared country codes: https://www.countrycalling.codes/guides/shared-country-codes
- International toll-free calling: https://www.countrycalling.codes/guides/international-toll-free-calling
- Call-failure troubleshooting: https://www.countrycalling.codes/guides/international-call-troubleshooting
- Roaming-cost avoidance: https://www.countrycalling.codes/guides/avoid-roaming-charges
- Travel eSIM, roaming pass and local SIM comparison: https://www.countrycalling.codes/guides/travel-esim-vs-roaming-vs-local-sim
- Country walkthroughs: https://www.countrycalling.codes/guides/country-dialing-walkthroughs
- Validation workflow: https://www.countrycalling.codes/guides/phone-number-validation
- Formatting errors: https://www.countrycalling.codes/guides/common-phone-number-formatting-errors
- Satellite and non-geographic codes: https://www.countrycalling.codes/guides/satellite-non-geographic-calling-codes
- Call routing and number portability: https://www.countrycalling.codes/guides/call-routing-number-portability
- Methodology: https://www.countrycalling.codes/methodology
- Format checker: https://www.countrycalling.codes/tools/format-checker
- Interactive developer docs: https://www.countrycalling.codes/developers
- Skill manifest: https://www.countrycalling.codes/skill.json
- MCP server: https://www.countrycalling.codes/api/mcp
- Official MCP Registry manifest: https://www.countrycalling.codes/server.json
- OpenAPI schema: https://www.countrycalling.codes/api/calling-codes/openapi.json
- Live API status: https://www.countrycalling.codes/api/calling-codes/status
- Phone format API: https://www.countrycalling.codes/api/phone/format
- Sitemap: https://www.countrycalling.codes/sitemap.xml
- Robots: https://www.countrycalling.codes/robots.txt

## International Format Rules

An international E.164 number contains a country calling code plus the national
significant number and has a maximum of 15 digits. The + sign signifies the
international prefix in written notation but is not an E.164 digit. An origin
exit prefix such as 00, 010, 011, or 0011 is not part of the destination number.

Do not apply "remove the leading zero" globally. The reviewed UK, German,
French, Japanese, Australian, South African, UAE, Indian fixed-line, and mainland
Chinese fixed-line patterns remove a domestic zero. Italian geographic numbers
retain their leading zero after +39. Brazil removes domestic routing digits and
any carrier-selection code before the two-digit area code. Singapore and the
ordinary NANP pattern do not add a general trunk zero.

Published X characters are safe placeholders, not dialable digits. Display
punctuation and extensions are not part of the stored E.164 destination.

## Operational Calling Guidance

- Forms and CRMs should accept human-friendly input, preserve the original,
  resolve explicit country context, normalize Unicode and punctuation, then
  store a canonical +digits field only after parsing succeeds. Extensions stay
  in a separate field or RFC 3966 tel URI parameter.
- A calling code is not always unique to one country. +1, +7, +39, +61, +262,
  and +599 are shared by multiple country or territory records in this dataset;
  later digits identify the destination range.
- Domestic toll-free numbers are not automatically reachable internationally.
  A UIFN uses +800 plus eight digits, but access still depends on subscriber
  activation and originating-network support.
- For a failed call, test number format, origin access, account permissions,
  carrier routing, destination filtering and VoIP signalling as separate layers.
- Before travel, compare the home carrier pass, travel eSIM, local SIM and Wi-Fi
  calling terms; set a deliberate data line and prevent the unused SIM from
  silently roaming.
- Compare travel connectivity by total trip cost, home-number access, device
  compatibility, activation risk, coverage and call/SMS support. A low price per
  GB does not include home-line roaming, taxes, top-ups or setup failures.
- Not every E.164 code is geographic. +870 identifies Inmarsat, while +881 is
  shared by Global Mobile Satellite Systems. +882 identifies international
  networks and +883 includes IoT/M2M resources and historical network uses.
  Consult current ITU assignment data before mapping an identification code.
- Number portability can change the current serving network without changing
  the visible phone number. Prefix allocation is not proof of the current
  carrier; portability and routing results require a source and timestamp.

## API Endpoints

### Search and filter

```http
GET /api/calling-codes?q=united%20kingdom
GET /api/calling-codes?code=GB
GET /api/calling-codes?dialCode=44
GET /api/calling-codes?region=Europe
GET /api/calling-codes?q=king&limit=5
GET /api/calling-codes?code=GB&include=examples
```

Query parameters:

- `q`: free-text search across country name, official name, ISO alpha-2, ISO
  alpha-3, calling code, capital, and area codes.
- `code`: exact ISO 3166-1 alpha-2 or alpha-3 code.
- `dialCode`: country calling code with or without +. It is not a full phone number.
- `region`: one of Africa, Americas, Asia, Europe, Oceania.
- `limit`: maximum result count, capped at 250.
- `include`: set to `examples` to add reviewed `dialingGuide` content.

The default response omits `dialingGuide` to keep broad directory payloads
compact. When present, `dialingGuide` includes safe display patterns,
transformation text, exception notes, primary source URLs, and `lastVerified`.

### Direct lookup

```http
GET /api/calling-codes/gb
GET /api/calling-codes/united-kingdom?include=examples
GET /api/calling-codes/44
GET /api/calling-codes/%2B44
```

The lookup path accepts ISO alpha-2, ISO alpha-3, country slug, exact country
name, official country name, or dial code. Dial-code matches may return multiple
countries because some calling codes are shared.

### Phone formatting

```http
POST /api/phone/format
Content-Type: application/json

{"phoneNumber":"(020) 7946 0123","countryCode":"GB"}
```

The phone formatter accepts a required `phoneNumber` and optional ISO alpha-2
`countryCode`. It uses reviewed country-specific rules, processes input
ephemerally, and returns an uncached formatting/plausibility result. It does not
perform a live carrier, HLR/HSS, MNP, ownership, reachability, or consent check.

### OpenAPI

```http
GET /api/calling-codes/openapi.json
```

Use operation `lookup_country_calling_code` for a read-only LLM tool.
The human-facing documentation and live request explorer are available at
https://www.countrycalling.codes/developers. Invalid REST parameters return HTTP 400 with field-level
details, and all REST routes support cross-origin GET requests.

### MCP

```json
{
  "mcpServers": {
    "country-calling-codes": {
      "url": "https://www.countrycalling.codes/api/mcp"
    }
  }
}
```

The hosted MCP endpoint exposes `lookup_country_calling_code` and
`format_international_phone_number`. Set `includeExamples` to true only when
the lookup answer needs reviewed formatting guidance or sources. Phone-format
input is processed ephemerally. MCP clients connect with the Streamable HTTP
transport. A normal browser GET returns discovery JSON, and
https://www.countrycalling.codes/server.json follows the official MCP Registry remote-server manifest
schema.

## Example Reviewed Response

```json
{
  "meta": {
    "standard": "ITU-T E.164",
    "resultCount": 1,
    "includesDialingGuide": true
  },
  "query": {
    "code": "GB",
    "include": "examples"
  },
  "countries": [
    {
      "name": "United Kingdom",
      "code": "GB",
      "dialCode": "+44",
      "trunkPrefix": "0",
      "dialingGuide": {
        "status": "published",
        "leadingZeroBehavior": "drop",
        "mobile": {
          "nationalDisplay": "07700 900XXX",
          "internationalDisplay": "+44 7700 900XXX"
        },
        "lastVerified": "2026-07-19",
        "sources": [
          {
            "publisher": "Ofcom",
            "title": "The National Telephone Numbering Plan",
            "url": "https://www.ofcom.org.uk/siteassets/resources/documents/phones-telecoms-and-internet/information-for-industry/numbering/other/national-numbering-plan.pdf?v=401943",
            "lastVerified": "2026-07-19"
          }
        ]
      }
    }
  ]
}
```

## Validation Boundaries

The lookup API and format checker provide static numbering-plan guidance. They
do not perform HLR/HSS, carrier, MNP, allocation, reachability, ownership, or
consent checks. A carrier or portability result from another provider is
time-sensitive. A provider-reported "active" result is not proof of identity,
current ability to answer, or consent. When control matters, use a short-lived
challenge and record its time and purpose.

## Reviewed Country Walkthroughs

### Origin-to-destination examples

The + form is portable and suitable for saved contacts. The access-prefix form
is a dial string for the named origin and must not be stored as part of the
destination number. X and CC are placeholders for subscriber digits and a
Brazilian carrier-selection code respectively.

| From | To | Mobile + format | Mobile via origin prefix | Landline + format | Landline via origin prefix | Reviewed page |
| --- | --- | --- | --- | --- | --- | --- |
| United States | United Kingdom | +44 7700 900XXX | 011 44 7700 900XXX | +44 20 7946 XXXX | 011 44 20 7946 XXXX | https://www.countrycalling.codes/call/united-kingdom-from-united-states |
| United Kingdom | United States | +1 202 555 01XX | 00 1 202 555 01XX | +1 212 555 01XX | 00 1 212 555 01XX | https://www.countrycalling.codes/call/united-states-from-united-kingdom |
| Germany | Italy | +39 3XX XXX XXXX | 00 39 3XX XXX XXXX | +39 06 XXXXXXXX | 00 39 06 XXXXXXXX | https://www.countrycalling.codes/call/italy-from-germany |
| Australia | Singapore | +65 8XXX XXXX | 0011 65 8XXX XXXX | +65 6XXX XXXX | 0011 65 6XXX XXXX | https://www.countrycalling.codes/call/singapore-from-australia |
| Singapore | Japan | +81 90 XXXX XXXX | 001 81 90 XXXX XXXX | +81 3 XXXX XXXX | 001 81 3 XXXX XXXX | https://www.countrycalling.codes/call/japan-from-singapore |
| Brazil | United States | +1 202 555 01XX | 00 CC 1 202 555 01XX | +1 212 555 01XX | 00 CC 1 212 555 01XX | https://www.countrycalling.codes/call/united-states-from-brazil |
| United States | India | +91 9XXX XXX XXX | 011 91 9XXX XXX XXX | +91 11 XXXXXXXX | 011 91 11 XXXXXXXX | https://www.countrycalling.codes/call/india-from-united-states |
| United States | Australia | +61 4XX XXX XXX | 011 61 4XX XXX XXX | +61 2 XXXX XXXX | 011 61 2 XXXX XXXX | https://www.countrycalling.codes/call/australia-from-united-states |
| United States | Germany | +49 15X XXXXXXXX | 011 49 15X XXXXXXXX | +49 30 XXXXXXXX | 011 49 30 XXXXXXXX | https://www.countrycalling.codes/call/germany-from-united-states |
| United Kingdom | India | +91 9XXX XXX XXX | 00 91 9XXX XXX XXX | +91 11 XXXXXXXX | 00 91 11 XXXXXXXX | https://www.countrycalling.codes/call/india-from-united-kingdom |
| Australia | United Kingdom | +44 7700 900XXX | 0011 44 7700 900XXX | +44 20 7946 XXXX | 0011 44 20 7946 XXXX | https://www.countrycalling.codes/call/united-kingdom-from-australia |
| Japan | United States | +1 202 555 01XX | 010 1 202 555 01XX | +1 212 555 01XX | 010 1 212 555 01XX | https://www.countrycalling.codes/call/united-states-from-japan |

### Destination-country quick reference

| Country | Calling code | Mobile pattern | Landline pattern | Leading-zero behavior | Verified |
| --- | --- | --- | --- | --- | --- |
| United States | +1 | +1 202 555 01XX | +1 212 555 01XX | none | 2026-07-19 |
| United Kingdom | +44 | +44 7700 900XXX | +44 20 7946 XXXX | drop | 2026-07-19 |
| Germany | +49 | +49 15X XXXXXXXX | +49 30 XXXXXXXX | drop | 2026-07-19 |
| France | +33 | +33 6 XX XX XX XX | +33 1 XX XX XX XX | drop | 2026-07-19 |
| India | +91 | +91 9XXX XXX XXX | +91 11 XXXXXXXX | drop | 2026-07-19 |
| China | +86 | +86 1XX XXXX XXXX | +86 10 XXXXXXXX | drop | 2026-07-19 |
| Japan | +81 | +81 90 XXXX XXXX | +81 3 XXXX XXXX | drop | 2026-07-19 |
| Australia | +61 | +61 4XX XXX XXX | +61 2 XXXX XXXX | drop | 2026-07-19 |
| Brazil | +55 | +55 11 9XXXX XXXX | +55 11 XXXX XXXX | conditional | 2026-07-19 |
| South Africa | +27 | +27 82 XXX XXXX | +27 11 XXX XXXX | drop | 2026-07-19 |
| Singapore | +65 | +65 8XXX XXXX | +65 6XXX XXXX | none | 2026-07-19 |
| United Arab Emirates | +971 | +971 50 XXX XXXX | +971 4 XXX XXXX | drop | 2026-07-19 |
| Italy | +39 | +39 3XX XXX XXXX | +39 06 XXXXXXXX | retain | 2026-07-19 |

## Dataset Summary

- Countries and territories: 233
- Unique calling codes: 203
- Reviewed country walkthroughs: 13
- Country-pair examples: 12
- Regions: Africa, Americas, Asia, Europe, Oceania
- Standard: ITU-T E.164

## Sample Directory Rows

| Country | ISO2 | ISO3 | Dial code | Region | Page |
| --- | --- | --- | --- | --- | --- |
| United States | US | USA | +1 | Americas | https://www.countrycalling.codes/country/united-states |
| Canada | CA | CAN | +1 | Americas | https://www.countrycalling.codes/country/canada |
| Bahamas | BS | BHS | +1 | Americas | https://www.countrycalling.codes/country/bahamas |
| Barbados | BB | BRB | +1 | Americas | https://www.countrycalling.codes/country/barbados |
| Anguilla | AI | AIA | +1 | Americas | https://www.countrycalling.codes/country/anguilla |
| Antigua and Barbuda | AG | ATG | +1 | Americas | https://www.countrycalling.codes/country/antigua-and-barbuda |
| British Virgin Islands | VG | VGB | +1 | Americas | https://www.countrycalling.codes/country/british-virgin-islands |
| United States Virgin Islands | VI | VIR | +1 | Americas | https://www.countrycalling.codes/country/united-states-virgin-islands |
| Cayman Islands | KY | CYM | +1 | Americas | https://www.countrycalling.codes/country/cayman-islands |
| Bermuda | BM | BMU | +1 | Americas | https://www.countrycalling.codes/country/bermuda |
| Grenada | GD | GRD | +1 | Americas | https://www.countrycalling.codes/country/grenada |
| Turks and Caicos Islands | TC | TCA | +1 | Americas | https://www.countrycalling.codes/country/turks-and-caicos-islands |
| Montserrat | MS | MSR | +1 | Americas | https://www.countrycalling.codes/country/montserrat |
| Northern Mariana Islands | MP | MNP | +1 | Oceania | https://www.countrycalling.codes/country/northern-mariana-islands |
| Guam | GU | GUM | +1 | Oceania | https://www.countrycalling.codes/country/guam |
| American Samoa | AS | ASM | +1 | Oceania | https://www.countrycalling.codes/country/american-samoa |
| Sint Maarten | SX | SXM | +1 | Americas | https://www.countrycalling.codes/country/sint-maarten |
| Saint Lucia | LC | LCA | +1 | Americas | https://www.countrycalling.codes/country/saint-lucia |
| Dominica | DM | DMA | +1 | Americas | https://www.countrycalling.codes/country/dominica |
| Saint Vincent and the Grenadines | VC | VCT | +1 | Americas | https://www.countrycalling.codes/country/saint-vincent-and-the-grenadines |