Tools

MSISDN decoder

Paste a number in any format — with +, with 00, with spaces or dashes — and we normalize it to the international E.164 format: country calling code identified and national number split out. Handy for cleaning MSISDN lists before an integration or a platform migration.

What an MSISDN is, and what E.164 is

The MSISDN (Mobile Station International Subscriber Directory Number) is a mobile line's phone number — what you'd dial to call it. ITU-T recommendation E.164 defines its international format: at most 15 digits, composed of the country calling code (1–3 digits) and the national significant number. Don't confuse MSISDN with IMSI: the IMSI identifies the subscriber inside the network and travels in signalling; the MSISDN is the line's public number, and a SIM can have several — or, like many data-only IoT SIMs, none routable for voice. In IoT integrations, strict E.164 (with + and no spaces) is what almost every API expects, including ours.

Frequently asked questions

What is a SIM's MSISDN?
It's the line's public phone number in international format: country calling code plus national number, up to 15 digits per ITU-T E.164. It's what shows up in a contact list — not to be confused with the IMSI (the subscriber identity on the network) or the ICCID (the physical card's serial number).
Do IoT SIMs have an MSISDN?
Almost always one is assigned for network-technical reasons, but on data-only plans it may not be routable for voice or public SMS. If your use case needs SMS (for example to wake a device or push commands), confirm with your provider that the MSISDN supports mobile-terminated SMS; on our plans you can enable it.
What's the difference between +34 and 0034?
None in the destination: + is the standard E.164 symbol for the international prefix and 00 is the common international dialling prefix in Europe (011 in the US). For storing numbers in databases and APIs always use the + form — it's unambiguous and it's what platforms expect.
Does this tool validate that the number exists?
No. It checks the structure (assigned country code and E.164 length) but doesn't query any operator, so it can't know whether the number is active or who it belongs to. National numbering plans aren't validated in detail either: a number can be structurally correct and unassigned.

Managing MSISDNs by the thousands?

Our API returns each SIM's ICCID, IMSI and MSISDN, and lets you activate, suspend and group lines in bulk.