One-time passwords: temporary codes that prove immediate access
Short answer: An OTP is a short-lived secret used for a single authentication step. It may arrive by text or voice, or be generated by an authenticator, depending on the service.
A code can expire or be superseded when another is requested. Enter it only in the genuine service flow and never reveal it to a person who unexpectedly asks for it.
Use the definition to check your setup
An OTP is a short-lived secret used for a single authentication step. It may arrive by text or voice, or be generated by an authenticator, depending on the service.
A code can expire or be superseded when another is requested. Enter it only in the genuine service flow and never reveal it to a person who unexpectedly asks for it.
One-time passwords: temporary codes that prove immediate access — points to check
| Review point | CallGlobal guidance |
|---|---|
| Concept | An OTP is a short-lived secret used for a single authentication step. It may arrive by text or voice, or be generated by an authenticator, depending on the service. |
| Configuration implication | A code can expire or be superseded when another is requested. Enter it only in the genuine service flow and never reveal it to a person who unexpectedly asks for it. |
| Product boundary | Consult the feature list; a glossary term does not identify an included capability. |
Where the CallGlobal line fits
Your number account provides the public telephone identity, its communication controls and the SIP credentials for compatible software. Other capabilities belong to the application or phone system you choose.
Review the live product feature list before relying on an additional function. Number porting, hosted IVR, voicemail, call recording and a public customer API are not included.
Protect the line and the account
- Keep account and SIP passwords private, including in support screenshots.
- Confirm the active rental term before relying on incoming communication.
- Use the complete international number and only an authorized caller identity.
Frequently asked questions
What does this term describe?
An OTP is a short-lived secret used for a single authentication step. It may arrive by text or voice, or be generated by an authenticator, depending on the service.
How does this affect practical configuration?
A code can expire or be superseded when another is requested. Enter it only in the genuine service flow and never reveal it to a person who unexpectedly asks for it.
Does every telephone concept name an included product feature?
No. A glossary explains terminology. The product feature page and your number dashboard identify the functions provided with a CallGlobal line.
Continue exploring
- two-factor authentication
- SMS verification
- non-VoIP numbers
- verification code not received
- real numbers vs free SMS sites
- WhatsApp use case
- Number porting: keeping the digits when changing provider
- PBX: the system behind extensions and business call routing
Sources
- IETF: RFC 6238, TOTP: Time-Based One-Time Password Algorithm (as of September 2026)
- IETF: RFC 4226, HOTP: An HMAC-Based One-Time Password Algorithm (as of September 2026)