Nexmo Conversion API
Browse all Nexmo APIs★ Only Publicly Available OpenAPI DocumentCommunicationsSms MessagingapiKey2 EndpointsREST
For Agents
Report SMS and voice 2FA conversion outcomes back to Nexmo so the platform can tune routing and reliability for future verification traffic.
Use for: I want to report a successful SMS 2FA verification back to Nexmo, Send conversion data for a voice OTP that the user completed, Confirm that a verification SMS message-id resulted in a real conversion, Mark a Nexmo voice call as not converted when the code was never entered
Not supported: Does not send messages, verify codes, or manage phone numbers — use for posting 2FA conversion outcomes back to Nexmo only.
The Nexmo Conversion API lets developers report back to Vonage whether a 2FA SMS or voice verification message was actually delivered and acted on by the recipient. Feeding this conversion signal back into the Nexmo platform helps optimise carrier routes, improve future delivery reliability, and surface fraudulent traffic patterns. The API exposes two simple POST endpoints, one for SMS and one for voice, each accepting a message-id, a delivered flag, and an optional timestamp.
Install Jentic One Beta
Connect the Nexmo Conversion API to your agent
Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the Nexmo Conversion 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.
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Step 1: Jentic One Host machine
# On the machine that will host your Jentic One instance:
curl -fsSL https://raw.githubusercontent.com/jentic/jentic-one/main/tools/install.sh | sh2
Step 2: Agent machine
# On the machine where your agent runs (keep this separate from the instance):
curl -fsSL https://raw.githubusercontent.com/jentic/jentic-one/main/tools/install.sh | 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 Nexmo Conversion API.
Report whether a 2FA SMS code was successfully entered by the end user
Report whether a 2FA voice call code was successfully entered by the end user
Attach a delivery timestamp to each conversion record for accurate latency tracking
Tag SMS message-ids returned by the SMS API with conversion status to improve routing
Tag voice call-ids returned by the Voice API with conversion status to improve routing
Use Cases
Patterns agents use Nexmo Conversion API for, with concrete tasks.
★ 2FA SMS conversion feedback
When an application sends a 2FA code via the Nexmo SMS API, the Conversion API closes the loop by reporting whether the user actually entered the code. Posting a delivered=true or delivered=false flag against the original message-id lets Nexmo learn which carrier routes deliver real conversions versus silent failures, which directly improves future deliverability.
POST /sms with message-id from a previously sent verification SMS and delivered=true once the user submits the correct code
Voice OTP conversion tracking
Applications that deliver one-time passwords by automated voice call can report whether the recipient successfully entered the spoken code. The /voice endpoint accepts the call-id returned by the Voice API along with a delivered flag, allowing Nexmo to discriminate between answered-and-converted, answered-but-abandoned, and undelivered call outcomes.
POST /voice with the call-id from a Voice API verification call, delivered=true, and the timestamp the user completed the code
Routing optimisation feedback loop
Operations and trust teams send batch conversion updates back to Nexmo at the end of each verification session so the platform can recalculate carrier-route quality. Reporting both successful and failed conversions, rather than only successes, gives the routing engine balanced signal and reduces silent failure rates over time.
Loop through yesterday's verification messages and POST /sms or /voice for each with the appropriate delivered flag and timestamp
AI agent posting verification outcomes via Jentic
An AI agent that orchestrates a sign-up flow can call the Nexmo Conversion API through Jentic immediately after the user completes verification. Jentic handles the API key and secret, so the agent simply searches for the conversion operation, supplies the message-id and delivered flag, and Jentic executes the POST against api.nexmo.com/conversions.
Search Jentic for 'report sms 2fa conversion to nexmo', load the /sms operation, and execute with message-id=MESSAGE_ID and delivered=true
Key Endpoints
2 endpoints — the nexmo conversion api lets developers report back to vonage whether a 2fa sms or voice verification message was actually delivered and acted on by the recipient.
METHOD
PATH
DESCRIPTION
POST
/sms
Report SMS 2FA conversion outcome
POST
/voice
Report voice OTP conversion outcome
POST
/sms
Report SMS 2FA conversion outcome
POST
/voice
Report voice OTP conversion outcome
Why Jentic?
Three things that make agents converge on Jentic-routed access.
Credential isolation
Nexmo apiKey and apiSecret are stored encrypted in the Jentic vault. Agents receive scoped access tokens, so the raw secret never enters the agent's prompt or logs.
Intent-based discovery
Agents search Jentic by intent (e.g. 'report sms 2fa conversion') and Jentic returns the POST /sms or POST /voice operation with the input schema, ready to execute.
Time to first call
Direct integration: half a day to wire up apiKey/apiSecret handling and post-verify hooks. Through Jentic: under 15 minutes — search, load, execute.
Related APIs
Alternatives and complements available in the Jentic catalogue.
FAQs
Specific to using Nexmo Conversion API through Jentic.
What authentication does the Nexmo Conversion API use?
The Conversion API uses Nexmo's standard apiKey and apiSecret query parameters, with optional apiSig for signed requests. Through Jentic these credentials live in the encrypted vault, so the agent only sees a scoped token and never the raw api_key or api_secret.
Can I report both SMS and voice conversions with the same API?
Yes. POST /sms accepts message-ids returned by the Nexmo SMS API and POST /voice accepts call-ids returned by the Nexmo Voice API. Both endpoints share the same delivered flag and timestamp parameters, so a single integration covers both verification channels.
What are the rate limits for the Nexmo Conversion API?
Vonage does not publish a hard per-second rate limit for the Conversion API and the OpenAPI spec does not encode one. In practice the endpoint is designed to absorb post-hoc batch reporting, so spreading conversion posts over the same window in which messages were sent is the safest pattern.
How do I report a converted SMS through Jentic?
Run pip install jentic, search for 'report sms 2fa conversion to nexmo', load the POST /sms operation, and execute with message-id, delivered=true, and an optional timestamp. Jentic injects the apiKey credentials and returns the Nexmo response.
Is the Nexmo Conversion API free?
Reporting conversion data does not incur a per-call charge from Vonage; the cost sits with the underlying SMS or voice verification message you originally sent. Only customers already using the Nexmo SMS or Voice APIs would have message-ids to report against.
Should I report failed conversions as well as successful ones?
Yes. Sending only delivered=true skews the routing engine because Nexmo cannot distinguish silent failures from messages you simply never followed up on. Posting delivered=false for OTPs that were never entered gives the platform balanced signal.
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