Nango Toolbox

When to use

• Any access to an external API.
• External API calls must go through Nango.
• Do not use MCPs, provider CLIs, or ad-hoc direct API calls outside Nango.

Configuration (required)

Resolve values in this order.

Secret key

1. NANGO_TOOLBOX_SECRET_KEY in the process environment
2. NANGO_TOOLBOX_SECRET_KEY in a local .env

If missing, ask the user to:

• create a Nango account: https://app.nango.dev/signup
• copy the secret key from Environment settings → Backend
• set NANGO_TOOLBOX_SECRET_KEY in their shell profile (offer to add it)

Compatibility: if other instructions refer to NANGO_SECRET_KEY, treat it as NANGO_TOOLBOX_SECRET_KEY.

Base URL

1. NANGO_SERVER_URL in the process environment
2. NANGO_SERVER_URL in a local .env
3. https://api.nango.dev

HTTP headers

• Authorization: Bearer <NANGO_TOOLBOX_SECRET_KEY>
• Content-Type: application/json
• Prefer JSON bodies over query params when both exist.

Discovery (use these first)

List integrations:

GET <base-url>/integrations
Authorization: Bearer <secret-key>

List connections for an integration:

GET <base-url>/connections?integrationId=<unique_key>
Authorization: Bearer <secret-key>

List deployed actions/syncs:

GET <base-url>/scripts/config
Authorization: Bearer <secret-key>

Choose integration (do this before connection)

• Check if an integration for your API is setup in Nango
• If not, set it up for the user:
  • If the API is OAuth and has Nango provided developer credentials, ask the user to enable it manually in the dashboard.
  • If the API is OAuth and doesn't have Nango developer credentials guide the user to get a client id & secret
  • If the API uses "OAuth client credentials", do not ask the user for client id & secret. Set the integration up and the user will enter them with the Connect Link.
  • In all other cases, set the integration up and proceed with creating a Connect link

Do not ask the user for any Connection specific parameters. Always let it enter these in the Connect link.

Choose integration + connection (required)

• Ensure the integration (provider) exists in Nango; create it via Nango HTTP API if needed.
• Fetch connections for the integration.
• If multiple connections exist and you cannot disambiguate, ask which connection_id to use.

If no connection exists, generate a connect session link:

POST <base-url>/connect/sessions
Authorization: Bearer <secret-key>
Content-Type: application/json

{
  "tags": { "end_user_id": "<user-firstname>" },
  "allowed_integrations": ["<unique_key>"]
}

Share data.connect_link directly with the user (expires in ~30 minutes). Do not send them to the dashboard.

Before provider calls, confirm required scopes on the connection (often credentials.raw.scope).

If scopes are insufficient, update scopes at the integration level, then ask for permission to delete/recreate the connection:

PATCH <base-url>/integrations/<unique_key>
Authorization: Bearer <secret-key>
Content-Type: application/json

{
  "credentials": {
    "type": "OAUTH2",
    "client_id": "<client_id>",
    "client_secret": "<client_secret>",
    "scopes": "scope1,scope2,scope3"
  }
}

Scopes are comma-separated (no spaces).

Access strategy

• Use Nango proxy for 1–2 simple provider calls and to explore the API.
• Use a Nango Action for multi-call logic, transformations, pagination orchestration, retries/error handling, or reuse.

Prefer reusing an existing deployed action (see GET <base-url>/scripts/config).

If you must create a new action, use the building-nango-functions-remotely skill and deploy before calling it. If the skill does not exist, offer to install it from https://github.com/NangoHQ/skills

Invoke a deployed action:

POST <base-url>/action/trigger
Authorization: Bearer <secret-key>
Provider-Config-Key: <unique_key>
Connection-Id: <connection_id>
Content-Type: application/json

{"action_name": "<action-name>", "input": {...}}

Docs

• https://nango.dev/docs
• https://nango.dev/docs/llms.txt
• https://nango.dev/docs/reference/api
• https://nango.dev/docs/spec.yaml

Nango maintains a docs page for each API it supports (find it in llms.txt). This page contains a link to the external APIs reference.