Agent-ready OpenAPI document · curated by JenticCommunicationsSms MessagingapiKey1 EndpointsREST
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For Agents
Send transactional and notification SMS messages from a Vonage virtual number or alphanumeric sender to E.164 phone numbers worldwide, with optional Unicode, binary, and delivery-receipt support.
Use for: I need to send a one-time password to a customer's phone, Send an SMS notification when a deployment finishes, Deliver a Unicode order confirmation to a Japanese phone number, Send a transactional SMS from an alphanumeric sender ID
Not supported: Does not handle inbound SMS reception, voice calls, or WhatsApp delivery - use for outbound SMS sending only.
Jentic publishes the only available OpenAPI specification for SMS API, keeping it validated and agent-ready. The Vonage SMS API sends one-way SMS messages from a Vonage virtual number or alphanumeric sender ID to mobile recipients in E.164 format, supporting text, Unicode, binary, WAP push, and vCard payloads. A single POST endpoint accepts the message, optional message class, status-report-request flag, callback URL, and TTL, returning delivery status and message reference IDs for each segment. API key and secret are passed as request parameters per Vonage's documented auth flow.
Install Jentic One Beta
Connect the SMS API to your agent
Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the SMS 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%2Fsms-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%2Fsms-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 SMS API.
Send transactional SMS messages from a Vonage virtual number or alphanumeric sender ID to any E.164 mobile number
Deliver Unicode (UCS-2) text for non-Latin alphabets and emoji-bearing notifications
Send binary SMS payloads with user data header support for application-to-handset delivery
Request delivery receipts via the status-report-req flag and receive callbacks at a configured URL
Set per-message time-to-live to drop SMS that have not been delivered within a freshness window
Tag outgoing messages with a client reference so downstream callbacks can be correlated to source records
Use Cases
Patterns agents use SMS API for, with concrete tasks.
★ One-Time Password Delivery
Send numeric or alphanumeric OTP codes to customers during sign-up or step-up authentication. The single POST /{format} endpoint accepts to, from, and text fields and returns a per-segment delivery status. For locales requiring Unicode digits or non-Latin disclaimers, set type=unicode. Use a short time-to-live so codes that fail to deliver are not retried after they have expired in the application layer.
POST /json with to=+15551234567, from=Acme, text='Your code is 482913', and ttl=300000 to send a five-minute OTP and return the message reference
Operational Alert Notifications
Push deployment, monitoring, or on-call alerts directly to engineer mobile numbers. The SMS API takes the alert text and routes it through Vonage's global carrier network, with delivery receipt callbacks to a webhook so the alerting system can confirm receipt. Alphanumeric sender IDs make alerts identifiable in supported countries, while numeric senders are used where alphanumeric is restricted.
POST /json with to=+447700900123, from=Monitor, text='CPU at 95% on web-03', and status-report-req=1 to send the alert and request a delivery receipt
International Notification Campaign
Deliver order confirmations, shipping updates, and authentication messages to customers globally. The SMS API supports Unicode for international markets, message-class control for class 0 flash SMS, and client-ref tagging so each send can be reconciled against the source CRM record. Long messages are segmented automatically and the response lists each segment's delivery status.
POST /json with to=+819012345678, from=Shop, type=unicode, text containing the kana confirmation message, and client-ref='order-9821' to send a shipping update
AI Agent SMS Delivery
Through Jentic, an AI agent sends SMS without storing the Vonage API key or secret. The agent searches Jentic with the intent 'send an SMS message', loads the input schema for POST /{format}, and executes with to, from, and text. Jentic injects the API key and secret as request parameters from your Jentic One instance, so the credentials never enter the agent's prompt context.
Use Jentic search query 'send an SMS message' to load POST /json, then execute with to, from, and text parameters to deliver a notification to a single recipient
Key Endpoints
1 endpoints — jentic publishes the only available openapi specification for sms api, keeping it validated and agent-ready.
METHOD
PATH
DESCRIPTION
POST
/{format}
Send an SMS in JSON or XML response format
POST
/{format}
Send an SMS in JSON or XML response format
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.
S
SMS API
- AI-Aware (A-)74/100
64
Foundational Compliance74
Developer Experience & Jentic Compatibility57
AI-Readiness & Agent Experience94
Agent Usability100
Security100
AI DiscoverabilityPowered by JenticScoring Framework 1.0.0 | Scoring Engine 0.4.0
Show dimension breakdown
64
Foundational Compliance
Base layer of spec validity and structural soundness.
Grade: BSignals: 4
96%
Lint Results
Aggregated quality score from linter diagnostics, weighted by severity.
100%
Resolution Completeness
Percentage of `$ref` references that resolve successfully.
0%
Specification Validity
Checks whether the API description parses successfully and conforms to its declared specification (e.g., OpenAPI).
60%
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
71%
Example Density
How richly the API is illustrated with examples.
100%
Example Validity
Percentage of examples that conform to their schemas.
25%
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.
57
AI-Readiness & Agent Experience
Semantic breadth, depth, and agent comprehension for AI systems.
Grade: C+Signals: 4
79%
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.
100
Security
Trust, risk posture, and security compliance.
Grade: A+Signals: 1
100%
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 Vonage SMS API by hand means passing your api_key and api_secret as request parameters, targeting the rest.nexmo.com host, and formatting the to, from, and text fields correctly on every send. Through Jentic you install once, import the SMS API from the API Directory, store the key and secret once, and your agent calls it.
Permission scoping
The recipient number travels in the request body, not the URL path, so scope your agent to the operations it needs: this API exposes only outbound message sending, and you decide whether that single send operation is in the allowed set.
Credential isolation
Your Vonage api_key and api_secret are stored once, encrypted, by your own Jentic One instance and injected as request parameters at execution time. They never enter the agent's prompt, logs, or context.
Intent-based discovery
Agents search Jentic by intent such as 'send an SMS message' and Jentic returns the POST /{format} operation with its input schema so the agent populates to, from, and text without browsing the reference docs.
Related APIs
Alternatives and complements available in the Jentic catalogue.
FAQs
Specific to using SMS API through Jentic.
Why is there no official OpenAPI spec for SMS API?
Vonage does not publish an OpenAPI specification. Jentic generates and maintains this spec so that AI agents and developers can call SMS API via structured tooling. It is validated against the live API and kept up to date. Get started with Jentic One, the self-hosted execution layer.
What authentication does the Vonage SMS API use?
The SMS API authenticates with your Vonage API key and API secret passed as api_key and api_secret request parameters on POST /{format}. Jentic stores both in your Jentic One instance and injects them at execution time, so agents never handle the raw secret.
Can I send Unicode SMS for non-Latin alphabets?
Yes. Set type=unicode on POST /{format} to send UCS-2 encoded text for languages such as Japanese, Arabic, Hindi, or messages containing emoji. Note that Unicode segments hold 70 characters instead of 160, so longer messages will be split into multiple billed parts.
How do I receive delivery receipts for outbound SMS?
Set status-report-req=1 on the POST /{format} request and configure a delivery receipt callback URL in your Vonage account dashboard. Vonage will POST status updates to that URL once the carrier confirms delivery. Use the message-id field in the response to correlate receipts to the original send.
Can I send SMS from an alphanumeric sender ID?
Yes - pass an 11-character alphanumeric string in the from parameter on POST /{format}. Some destination countries (including the United States and Canada) require a numeric long code or short code instead, so check the Vonage country support matrix before relying on alphanumeric for global traffic.
How do I send an SMS through Jentic?
Run pip install jentic, then use the Jentic search query 'send an SMS message' to discover POST /{format}. Load the schema, then execute with to, from, and text - Jentic resolves the api_key and api_secret from the vault. Run it through Jentic One, the self-hosted execution layer.
Can I limit what my agent is allowed to do with the Vonage SMS API?
Yes. Because Jentic One is self-hosted, your own rules decide which operations and credentials the agent may use, and this API exposes only a single outbound send operation, POST /{format}, so you choose whether that one send is in the agent's allowed set. The recipient number travels in the request body rather than the URL path, and your Vonage api_key and api_secret are injected at execution time, so the agent never handles the raw secret. If you leave the send operation out of the allowed set, the agent cannot dispatch any SMS.
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