canonical: https://jentic.com/apis/nexmo.com/nexmo-conversion

# Nexmo Conversion API

Jentic publishes the only available OpenAPI specification for Nexmo Conversion API, keeping it validated and agent-ready. The Conversion API lets senders report whether a 2FA SMS or voice call ultimately reached and was acted on by the recipient. Nexmo (now Vonage) feeds these signals into its Adaptive Routing system, which continuously rebalances carrier paths to favour those producing higher real-world delivery success. The surface is intentionally tiny: two POST endpoints, one for SMS conversions and one for voice conversions.

## For AI agents

Report SMS and voice 2FA conversion outcomes to Nexmo so its routing engine can learn which carriers actually deliver. Two POST endpoints: /sms and /voice.

## Scope

Does not send messages, run Verify flows, or expose delivery analytics dashboards - use only for posting per-message conversion outcomes that feed Nexmo's Adaptive Routing.

## Capabilities

- Report whether a 2FA SMS reached the user via POST /sms with the original message-id and a delivered timestamp
- Report whether a 2FA voice call completed successfully via POST /voice with the call message-id
- Improve future SMS and voice routing by feeding Nexmo's Adaptive Routing engine real conversion outcomes
- Submit a delivered flag and ISO-8601 timestamp alongside each conversion to record when the user actually engaged
- Authenticate each conversion report with api_key, api_secret, and optional sig query parameters

## Use cases

### 2FA SMS conversion reporting

After a user enters a one-time code received by SMS, the application reports the outcome to Nexmo so its Adaptive Routing engine can prefer carriers that actually deliver. The Conversion API accepts the original message-id, a delivered boolean, and an optional ISO-8601 timestamp. There is a single POST /sms endpoint, and integration is typically a one-line call from the OTP verification handler.

Example prompt: POST to /sms with message-id from the original SMS send, delivered=true, and the current ISO-8601 timestamp using api_key and api_secret query parameters.

### Voice OTP outcome logging

When a user receives a verification code by voice call, the application can report back whether the call connected and the code was used. POST /voice takes the same message-id, delivered, and timestamp shape as the SMS variant. This is the only voice-specific endpoint on the API and is used purely to improve future voice routing decisions.

Example prompt: POST to /voice with message-id from the original voice call response, delivered=true, and timestamp in ISO-8601 format.

### Closing the loop on Verify flows from an agent

An AI agent that sends 2FA messages on behalf of a user can complete the loop by reporting the verification outcome through Jentic. After a Verify or Messages send, once the user enters the correct code, the agent issues a single conversion call so future sends route through better-performing carriers. Discovery is by intent ('report 2fa conversion'); execution is one POST per outcome.

Example prompt: Search Jentic for 'report 2fa conversion to nexmo', load the /sms operation schema, and execute it with the message-id, delivered=true, and current timestamp.

## Key endpoints

| Method | Path | Description |
| --- | --- | --- |
| POST | `/sms` | Report whether an SMS message was successfully delivered |
| POST | `/voice` | Report whether a voice call was successfully delivered |

## Key resources

- **SMS Conversion** — Report the outcome of an SMS message via POST /sms
- **Voice Conversion** — Report the outcome of a voice call via POST /voice

## Why Jentic

- **Setup:** Wiring the Nexmo Conversion API by hand means appending your api_key and api_secret to every query string and targeting the api.nexmo.com/conversions host for each conversion post. Through Jentic you install once, import the Conversion API from the API Directory, store the api_key and api_secret once, and your agent calls it.
- **Permission scoping:** The Conversion API carries the message id in the request body, so scoping is by operation rather than by resource: limit the agent to the operations it needs, such as posting an SMS conversion or a voice conversion. You credit it only with the conversion-reporting calls it requires, and nothing beyond that set runs.
- **Credential handling:** Your Nexmo api_key and api_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.
- **Discovery method:** Agents search Jentic by intent such as 'report a 2FA conversion to Nexmo', and Jentic returns the matching POST /sms or POST /voice operation with its input schema so the agent calls the right endpoint without browsing the reference docs.

## Related APIs

- **Nexmo Messages API** — Sends the SMS, MMS, WhatsApp, Viber, and Messenger messages whose outcomes you then report through Conversion
- **Twilio API** — Twilio offers Verify and Messaging Insights as a competing approach to 2FA delivery and outcome tracking
- **MessageBird SMS API** — MessageBird's SMS API is a direct competitor for transactional and 2FA SMS delivery in Europe

## FAQ

### Why is there no official OpenAPI spec for Nexmo Conversion API?

Vonage (formerly Nexmo) does not publish an OpenAPI specification. Jentic generates and maintains this spec so that AI agents and developers can call Nexmo Conversion 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 Nexmo Conversion API use?

It accepts api_key and api_secret as query parameters, with an optional sig parameter for signed requests. Through Jentic these credentials are stored encrypted in the vault and injected at execution time, so the agent never sees raw account secrets.

### Can I report both SMS and voice conversions through this API?

Yes. POST /sms reports SMS outcomes and POST /voice reports voice call outcomes. Both take the same body shape: message-id from the original send, a delivered boolean, and an optional ISO-8601 timestamp.

### What are the rate limits for the Nexmo Conversion API?

The OpenAPI spec does not declare rate limits. Conversion reporting is generally low-volume relative to message sends, and Vonage applies account-level throttles documented at developer.nexmo.com rather than per-endpoint quotas.

### How do I report a successful 2FA SMS through Jentic?

Search Jentic for 'report 2fa conversion to nexmo', load the POST /sms operation, and execute it with the message-id from your original Messages or SMS send response, delivered=true, and the timestamp at which the user verified.

### Does this API affect billing or simply improve routing?

Conversion reporting does not generate charges or refunds. The data is used by Nexmo's Adaptive Routing system to choose better carriers on subsequent sends, so the financial impact is indirect via higher delivery rates.

### Can I limit what my agent is allowed to do with the Nexmo Conversion API?

Yes. Because you run Jentic One yourself, your own rules decide which operations the agent may call, and this API scopes by operation rather than by resource. You can allow only the calls you need, such as posting an SMS conversion to POST /sms or a voice conversion to POST /voice, and nothing outside that set will run. Your Nexmo api_key and api_secret are held by your own instance and injected at execution time, so the agent reports conversion outcomes without ever seeing the raw account secrets.