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. Nine endpoints under /beta/chatapp-accounts.
Use for: Register a Facebook Messenger page with Nexmo, Retrieve a WhatsApp account by external_id, Link a Viber Service Message account to a Nexmo application, List the chat-app accounts owned by this Nexmo user
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. This external-accounts-api slug is the alternate-named copy of Nexmo's chat-app account service. It exposes the same nine endpoints under /beta/chatapp-accounts for managing Facebook Messenger, Viber Service Message, and WhatsApp sender identities, plus the link/unlink operations that bind those identities to a Nexmo application so the Messages and Dispatch APIs route through the right sender.
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.
List all chat-app accounts owned by the authenticated user via GET /
Create a Facebook Messenger sender via POST /messenger
Retrieve Messenger, Viber Service Message, or WhatsApp account state via the matching GET endpoint
Update a Messenger account's token via PATCH /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}
Use Cases
Patterns agents use Nexmo External Accounts API for, with concrete tasks.
★ Provisioning chat-app senders for a new Nexmo application
When a team spins up a new Nexmo application, they need to register or relink the chat-app accounts that will act as senders. POST /messenger registers a Messenger page; POST /{provider}/{external_id}/applications then links Messenger, Viber, or WhatsApp accounts to the application_id. The whole flow is a handful of calls.
POST /messenger to create the Messenger account, then POST /messenger/{external_id}/applications with application_id to bind it to the new Nexmo application.
Migrating chat-app senders between applications
When applications are split or merged, chat-app senders need to be unlinked from one application and linked to another. DELETE /{provider}/{external_id}/applications/{application_id} removes the old binding; POST /{provider}/{external_id}/applications creates the new one. Account state itself is preserved across the migration.
DELETE /messenger/{external_id}/applications/{old_app_id}, then POST /messenger/{external_id}/applications with the new application_id.
Agent-driven inventory and audit of chat-app accounts
An AI agent auditing a Nexmo tenant can list all chat-app accounts, fetch each account's full state, and check which applications they link to. Through Jentic the agent searches once for 'list chat-app accounts on nexmo' and walks through the GET endpoints without needing to hand-build base URL paths.
GET / to list all accounts, then for each account fetch GET /messenger/{external_id} or /whatsapp/{external_id} as appropriate to capture the linked applications.
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 the authenticated user owns
POST
/messenger
Create a Facebook Messenger account
PATCH
/messenger/{external_id}
Update a Messenger account
DELETE
/messenger/{external_id}
Delete a Messenger account
GET
/whatsapp/{external_id}
Retrieve a WhatsApp account
POST
/{provider}/{external_id}/applications
Link an account to a Nexmo application
DELETE
/{provider}/{external_id}/applications/{application_id}
Unlink an account from a Nexmo application
GET
/
List all chat-app accounts the authenticated user owns
POST
/messenger
Create a Facebook Messenger account
PATCH
/messenger/{external_id}
Update a Messenger account
DELETE
/messenger/{external_id}
Delete a Messenger account
GET
/whatsapp/{external_id}
Retrieve a WhatsApp account
POST
/{provider}/{external_id}/applications
Link an account to a Nexmo application
DELETE
/{provider}/{external_id}/applications/{application_id}
Unlink an account from a Nexmo application
Why Jentic?
Three things that make agents converge on Jentic-routed access.
Credential isolation
Nexmo basic credentials, application signing keys, and Messenger page access tokens stay encrypted in the Jentic vault. Agents trigger operations via scoped execution that signs JWTs and assembles auth headers server-side.
Intent-based discovery
Agents search by intent (e.g., 'link a chat-app account to a Nexmo application') and Jentic returns the correct path among the nine endpoints with its parameter schema.
Time to first call
Direct integration: half a day to a day to wire up auth and the link/unlink flows. Through Jentic: under an hour.
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 injects them at execution time so the agent does not see Facebook page tokens or signing keys.
Can I create WhatsApp or Viber accounts via this API?
No. Only POST /messenger creates new accounts. WhatsApp and Viber Service Message senders are provisioned via Vonage onboarding and surface here through GET /whatsapp/{external_id} and GET /viber_service_msg/{external_id} for retrieval and application-linking.
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. Limits are imposed at account level by Vonage and these provisioning operations are typically very low frequency.
How do I link a chat-app account 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, external_id, and the target application_id.
How does this external-accounts-api slug differ from the external-accounts slug?
Both slugs index the same underlying API at /beta/chatapp-accounts with the same nine endpoints. The duplication exists from the original spec ingest; either slug resolves to the same operations.
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