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For Agents
Search Vonage's virtual number inventory, buy and cancel numbers, and configure their inbound SMS and voice webhooks programmatically.
Use for: I want to buy a US virtual number that supports SMS, Search for available toll-free numbers in the United Kingdom, List all the numbers my Nexmo account currently owns, Update the voice webhook URL for one of my numbers
Not supported: Does not send messages, place calls, or port existing numbers - use for virtual number provisioning and configuration only.
The Nexmo Numbers API lets developers search, buy, configure, and cancel virtual phone numbers across the countries Vonage supports. Each number can be wired to receive SMS or voice traffic and routed to a webhook, an application, or a SIP endpoint. The API exposes five operations covering inventory search, purchase, update, cancellation, and listing of currently owned numbers, and is the foundation that the SMS, Voice, and Messages APIs sit on top of.
Install Jentic One Beta
Connect the Numbers API to your agent
Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the Numbers API, or any other public or private API you need. You set the rules, the agent never sees your credentials, and every call is logged.
Two steps, two machines. Install the instance in a safe environment, then register your agent from wherever it runs.
1
Step 1: Jentic One Host machine
# On the machine that will host your Jentic One instance:
curl -fsSL "https://jentic.com/install.sh?src=apis&api=%2Fapis%2Fnexmo.com%2Fnexmo-numbers-api" | sh2
Step 2: Agent machine
# On the machine where your agent runs (keep this separate from the instance):
curl -fsSL "https://jentic.com/install.sh?src=apis&api=%2Fapis%2Fnexmo.com%2Fnexmo-numbers-api" | sh
jentic register # connects your agent to your Jentic One instanceJentic One is in public beta. The setup above keeps your agent separate from the instance, which is what you want before using real credentials: an agent running as the same OS user as Jentic One can read its stored keys directly. Just evaluating? A single local install is fine to start. See the secure deployment guide for the tiers.
Capabilities
What an agent can do with Numbers API.
Search Vonage's inventory for available virtual numbers by country and feature
Buy a virtual number in a specific country and assign it to your account
Update an owned number's inbound SMS and voice webhook configuration
Cancel a previously purchased number to stop monthly rental charges
List every virtual number currently owned by the account with status and capability
Use Cases
Patterns agents use Numbers API for, with concrete tasks.
★ Provisioning a new SMS sender
When an application needs a dedicated long-code or toll-free sender, the team calls /number/search to find available inventory in the target country, /number/buy to purchase it, and /number/update to wire the inbound webhook to their application. The whole provisioning flow takes three API calls and replaces a manual portal-based purchase.
Call GET /number/search?country=US&features=SMS, pick the first MSISDN, then POST /number/buy with country and msisdn
Inbound webhook reconfiguration
When a service migrates to a new domain or splits inbound SMS and voice handlers across services, operators call /number/update for each owned number to point moHttpUrl and voiceCallbackValue at the new endpoints. Doing this through the API rather than the portal keeps the configuration in version control and reproducible across environments.
POST /number/update with country, msisdn, and the new moHttpUrl pointing at https://api.example.com/inbound-sms
Number portfolio audit
Finance and operations teams call /account/numbers to list every number the account holds, including capabilities, country, and current webhook target. The output drives quarterly audits to cancel unused numbers, confirm two-region failover coverage, and reconcile the bill against the active inventory.
GET /account/numbers and group the response by country and feature to produce an inventory report
AI agent number provisioning via Jentic
An AI agent that orchestrates messaging campaigns can request a fresh sender programmatically through Jentic. The agent calls the search operation, picks an MSISDN that supports SMS in the target country, and executes the buy operation, all without ever holding the raw apiKey/apiSecret pair.
Search Jentic for 'buy a virtual phone number for sms', load /number/buy, and execute with country=US and the chosen msisdn
Key Endpoints
5 endpoints — the nexmo numbers api lets developers search, buy, configure, and cancel virtual phone numbers across the countries vonage supports.
METHOD
PATH
DESCRIPTION
GET
/account/numbers
List numbers owned by the account
GET
/number/search
Search available numbers in inventory
POST
/number/buy
Purchase a virtual number
POST
/number/update
Update webhook configuration on an owned number
POST
/number/cancel
Release a number and stop billing
GET
/account/numbers
List numbers owned by the account
GET
/number/search
Search available numbers in inventory
POST
/number/buy
Purchase a virtual number
POST
/number/update
Update webhook configuration on an owned number
POST
/number/cancel
Release a number and stop billing
Jentic AI Readiness Score
This API is usable in Jentic One now. Its AI-readiness score against Jentic's framework shows where it stands today and where improvements would make it even easier for agents to use.
N
Numbers API
- AI-Aware (A-)72/100
100
Foundational Compliance74
Developer Experience & Jentic Compatibility55
AI-Readiness & Agent Experience94
Agent Usability50
Security100
AI DiscoverabilityPowered by JenticScoring Framework 1.0.0 | Scoring Engine 0.4.0
Show dimension breakdown
100
Foundational Compliance
Base layer of spec validity and structural soundness.
Grade: A+Signals: 4
99%
Lint Results
Aggregated quality score from linter diagnostics, weighted by severity.
100%
Resolution Completeness
Percentage of `$ref` references that resolve successfully.
100%
Specification Validity
Checks whether the API description parses successfully and conforms to its declared specification (e.g., OpenAPI).
100%
Structural Integrity
Structural correctness score based on schema issues using logarithmic dampening.
74
Developer Experience & Jentic Compatibility
Clarity, completeness, and ingestion readiness for developers and tooling.
Grade: A-Signals: 4
46%
Example Density
How richly the API is illustrated with examples.
100%
Example Validity
Percentage of examples that conform to their schemas.
50%
Response Coverage
Percentage of operations with complete response definitions (success, client error, server error).
100%
Tooling Readiness
Health of API ingestion, bundling, and resolution within Jentic pipelines.
55
AI-Readiness & Agent Experience
Semantic breadth, depth, and agent comprehension for AI systems.
Grade: CSignals: 4
68%
Description Coverage
Coverage of descriptions across API elements.
0%
Error Standardization
Coverage of RFC 9457 Problem Details for error responses.
100%
OperationId Quality
Coverage, uniqueness, and casing consistency of operationIds for AI inference.
50%
Summary Coverage
Coverage of summaries across operations/tags/info.
94
Agent Usability
Functional utility, complexity comfort, and AI orchestration readiness.
Grade: A+Signals: 1
94%
Complexity Comfort
Agent comfort level based on API operational and structural complexity.
50
Security
Trust, risk posture, and security compliance.
Grade: C-Signals: 1
50%
Authentication Strength
Average quality of security schemes based on authentication method strength (weakest link for OAuth2).
100
AI Discoverability
Findability, semantic richness, and reasoning readiness.
Grade: A+Signals: 1
100%
Descriptive Richness
Clarity and depth of descriptions across API elements.
Score it yourself
Every API in the directory is allowlisted, so you can re-score it with no key required.
npx @jentic/api-scorecard-cli score <openapi-url>Why Jentic?
What agents get from Jentic-routed access to this vendor.
Setup
Wiring the Numbers API by hand means setting the X-API-Key and apiSecret headers on every request and targeting the rest.nexmo.com host for search and provisioning calls. Through Jentic you install once, import the Numbers API from the API Directory, store the API key and secret once, and your agent calls it.
Permission scoping
The Numbers API carries the number and country in the request body or query, so scoping is by operation rather than by resource: limit the agent to the operations it needs, such as searching available numbers and updating configuration. You choose the operations it may call, so destructive ones like buying or cancelling a number are not included unless you add them.
Credential isolation
Your Nexmo API key and secret are stored once, encrypted, by your own Jentic One instance and injected at execution time. They never enter the agent's prompt, logs, or context.
Intent-based discovery
Agents search Jentic by intent such as 'buy a virtual phone number for SMS' or 'list my Nexmo numbers', and Jentic returns the matching operation with its input schema so the agent calls the right endpoint without browsing the reference docs.
Related APIs
Alternatives and complements available in the Jentic catalogue.
FAQs
Specific to using Numbers API through Jentic.
What authentication does the Nexmo Numbers API use?
The Numbers API uses apiKey and apiSecret query parameters on every request to rest.nexmo.com. Through Jentic those credentials live in the encrypted vault, so an agent only ever sees a scoped access token and never the raw api_secret.
Can I search and buy a number in a single API call?
No - purchase is a two-step flow on purpose. First call GET /number/search with the country and feature filters, then call POST /number/buy with a specific msisdn from the result. Splitting the steps lets the application show inventory to a user before charging the account.
What are the rate limits for the Numbers API?
Vonage does not encode a numeric rate limit in the OpenAPI spec. The provisioning endpoints are not designed for high concurrency - bulk buys should be serialised, and /account/numbers should be cached rather than polled aggressively.
How do I update an inbound SMS webhook through Jentic?
Run pip install jentic, search for 'update inbound sms webhook for nexmo number', and Jentic returns POST /number/update. Execute with country, msisdn, and moHttpUrl set to your new endpoint, and Jentic returns the updated number record.
Can I get a refund for a number I just bought?
Calling POST /number/cancel stops the monthly rental immediately, but Vonage's commercial terms govern any pro-rata refund and that policy is not exposed via the API. Numbers purchased and cancelled in quick succession should be reconciled against your account's billing rules.
What features can I filter on when searching numbers?
The /number/search endpoint accepts a features query parameter that supports SMS, VOICE, and MMS, plus a type parameter for landline, mobile-lvn, and toll-free. Combine them with country and pattern to narrow inventory to exactly what your application needs.
Can I limit what my agent is allowed to do with the Nexmo Numbers API?
Yes. Because your Jentic One instance is self-hosted, your own rules decide which operations and credentials the agent can use, and the Numbers API scopes by operation rather than by resource. You can allow the agent only the calls it needs, such as GET /number/search and POST /number/update to reconfigure webhooks, while withholding the destructive POST /number/buy and POST /number/cancel operations unless you explicitly add them. Your Nexmo API key and secret stay stored and injected at execution time, so the agent runs only the operations you permit and never sees the raw secret.
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