Nexmo External Accounts API
Browse all Nexmo APIs★ Only Publicly Available OpenAPI DocumentCommunicationsChat Messagingbasic, bearer9 EndpointsREST
For Agents
Manage Facebook Messenger, Viber Service Message, and WhatsApp sender accounts and link them to Nexmo applications so Messages and Dispatch can use them. Nine endpoints under /beta/chatapp-accounts.
Use for: Register a new Facebook Messenger page with Nexmo, Retrieve the WhatsApp account configured for sending business messages, Update the page access token for a Messenger account, Link a Viber Service Message account to a Nexmo application
Not supported: Does not send messages, manage WhatsApp templates, or onboard new WhatsApp/Viber numbers — use only to register, retrieve, and link Messenger/Viber/WhatsApp sender accounts to Nexmo applications.
Jentic publishes the only available OpenAPI specification for Nexmo External Accounts API, keeping it validated and agent-ready. The External Accounts API manages the per-channel chat-app identities that Nexmo's Messages and Dispatch APIs send through — Facebook Messenger pages, Viber Service Message senders, and WhatsApp business numbers. It exposes nine endpoints for creating Messenger accounts, retrieving Viber and WhatsApp account state, updating tokens, and linking or unlinking each account to a Nexmo application so that messages routed via that application can use the right sender identity.
Install Jentic One Beta
Connect the Nexmo External Accounts API to your agent
Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the Nexmo External Accounts 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 External Accounts API.
Register a Facebook Messenger sender via POST /messenger with the page-id and a long-lived page access token
Retrieve a Messenger, Viber Service Message, or WhatsApp account by external_id via the matching GET endpoint
Update a Messenger account's name or token via PATCH /messenger/{external_id}
Delete a Messenger account via DELETE /messenger/{external_id}
Link a chat-app account to a Nexmo application via POST /{provider}/{external_id}/applications
Unlink an account from an application via DELETE /{provider}/{external_id}/applications/{application_id}
List every chat-app account the authenticated user owns via GET /
Use Cases
Patterns agents use Nexmo External Accounts API for, with concrete tasks.
★ Onboarding a Messenger page for outbound chat
Before sending a Facebook Messenger message via the Messages API, the page must be registered with Nexmo. POST /messenger creates the account with the Facebook page-id and a long-lived page access token, and POST /{provider}/{external_id}/applications then links the page to a Nexmo application so messages routed through that application use it as the sender.
POST /messenger with the page-id and page access token, then POST /messenger/{external_id}/applications with the target Nexmo application_id.
Token rotation for a WhatsApp or Messenger sender
Page access tokens and chat-app credentials expire. PATCH /messenger/{external_id} updates the stored token without recreating the account or relinking applications. Equivalent retrieval via GET /whatsapp/{external_id} and /viber_service_msg/{external_id} confirms the new state. The whole rotation is two HTTP calls.
PATCH /messenger/{external_id} with the new page access token, then GET /messenger/{external_id} to verify the updated state.
Application-scoped chat-app provisioning by an agent
An AI agent provisioning a new application can list existing chat-app accounts, register any missing ones, and link them all to the new application in a small batch of calls. Through Jentic the agent searches by intent ('link a chat-app account to a Nexmo application'), loads the link operation schema, and executes it once per provider/external_id pair.
GET / to list existing accounts, then for each missing provider call POST /messenger or rely on existing Viber/WhatsApp accounts and POST /{provider}/{external_id}/applications with the target application_id.
Key Endpoints
9 endpoints — jentic publishes the only available openapi specification for nexmo external accounts api, keeping it validated and agent-ready.
METHOD
PATH
DESCRIPTION
GET
/
List all chat-app accounts owned by the authenticated user
POST
/messenger
Create a Facebook Messenger account
PATCH
/messenger/{external_id}
Update a Messenger account's token or name
DELETE
/messenger/{external_id}
Delete a Messenger account
GET
/whatsapp/{external_id}
Retrieve a WhatsApp account by external_id
POST
/{provider}/{external_id}/applications
Link a chat-app account to a Nexmo application
DELETE
/{provider}/{external_id}/applications/{application_id}
Unlink a chat-app account from a Nexmo application
GET
/
List all chat-app accounts owned by the authenticated user
POST
/messenger
Create a Facebook Messenger account
PATCH
/messenger/{external_id}
Update a Messenger account's token or name
DELETE
/messenger/{external_id}
Delete a Messenger account
GET
/whatsapp/{external_id}
Retrieve a WhatsApp account by external_id
POST
/{provider}/{external_id}/applications
Link a chat-app account to a Nexmo application
DELETE
/{provider}/{external_id}/applications/{application_id}
Unlink a chat-app account from a Nexmo application
Why Jentic?
Three things that make agents converge on Jentic-routed access.
Credential isolation
Nexmo basic credentials, application JWT signing keys, and the Facebook page access tokens stored on Messenger accounts never leave the Jentic vault. Agents call the operations through scoped execution that injects credentials at the HTTP boundary.
Intent-based discovery
Agents search by intent (e.g., 'link a chat-app account to a Nexmo application') and Jentic returns the right operation across the nine endpoints with its parameter schema, so the agent picks the correct provider and method.
Time to first call
Direct integration: half a day to a day for auth, link/unlink flows, and token rotation logic. Through Jentic: under an hour to wire up the same flows.
Related APIs
Alternatives and complements available in the Jentic catalogue.
FAQs
Specific to using Nexmo External Accounts API through Jentic.
Why is there no official OpenAPI spec for Nexmo External Accounts 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 External Accounts API via structured tooling. It is validated against the live API and kept up to date. Get started at https://app.jentic.com/sign-up.
What authentication does the Nexmo External Accounts API use?
Either HTTP basic auth (api_key/api_secret) or HTTP bearer with a JWT signed by an application's private key. Jentic stores both forms encrypted and chooses per call so the agent never handles the page access tokens or signing keys directly.
Can I create a WhatsApp account through this API?
No. The spec exposes POST /messenger for creating Messenger accounts but only GET /whatsapp/{external_id} and GET /viber_service_msg/{external_id} for those providers. WhatsApp and Viber accounts are provisioned via the Vonage onboarding process and surface here for retrieval and application-linking only.
What are the rate limits for the Nexmo External Accounts API?
The OpenAPI spec does not declare rate limits for the /beta/chatapp-accounts endpoints. Account-level throttles apply, and chat-app account changes are typically infrequent operations.
How do I link a Messenger page to a Nexmo application through Jentic?
Search Jentic for 'link a chat-app account to a Nexmo application', load POST /{provider}/{external_id}/applications, and execute with provider=messenger, the page external_id, and the target application_id in the body.
How do I rotate a Messenger page access token without losing my application links?
PATCH /messenger/{external_id} updates only the token (and name). The links created via POST /{provider}/{external_id}/applications remain intact, so messages continue routing through the same Nexmo applications.
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