Windmill Resources

Resources store credentials and configuration for external services.

File Format

Resource files use the pattern: {path}.resource.json

Example: f/databases/postgres_prod.resource.json

Resource Structure

{
  "value": {
    "host": "db.example.com",
    "port": 5432,
    "user": "admin",
    "password": "$var:g/all/db_password",
    "dbname": "production"
  },
  "description": "Production PostgreSQL database",
  "resource_type": "postgresql"
}

Required Fields

• value - Object containing the resource configuration
• resource_type - Name of the resource type (e.g., "postgresql", "slack")

Agents

An agent, as the Agents page lists it, is a resource of type ai_agent. Its value holds the agent's provider, system prompt, tools and memory settings, and a flow step uses a saved agent by linking its path.

Variable References

Reference variables in resource values:

{
  "value": {
    "api_key": "$var:g/all/api_key",
    "secret": "$var:u/admin/secret"
  }
}

Reference formats:

• $var:g/all/name - Global variable
• $var:u/username/name - User variable
• $var:f/folder/name - Folder variable

Secrets

Never put a secret (password, API key, token) inline in a resource value. Store it in a secret variable and reference that variable as $var:<path>.

• $var:<path> is a reference, not a value: it resolves to the variable's value at run time. Never invent a value for a variable.
• A resource that references a variable needs the variable to exist first, so create or deploy the variable before the resource.
• A secret's plaintext never goes in a file of the repo: a .variable.yaml holding it would be committed. Ask the user to create the secret on the workspace instead, e.g. wmill variable add '<value>' <path> (a secret by default), then reference it by path.

Resource References

Reference other resources:

{
  "value": {
    "database": "$res:f/databases/postgres"
  }
}

Passing a Resource or Variable as a Run Argument

A script or flow argument typed as a resource (schema format: resource-<type>) is passed as the bare string $res:<path> — the whole argument value. Same for a variable, with $var:<path>. This applies everywhere job arguments are supplied: wmill script run/preview, wmill flow run/preview, the runScriptByPath / runFlowByPath API, a schedule's args, a trigger's configured static args.

{
  "db": "$res:f/databases/postgres_prod",
  "api_token": "$var:g/all/api_token"
}

The reference is resolved when the job runs, under the job's run-as identity — the caller for an ordinary run, but the configured principal for a schedule, a trigger, or a runnable set to run on behalf of someone else. The run fails if that identity cannot read the referenced resource or variable.

Never wrap it in an object. The resolver only rewrites a JSON value that is a string starting with $res: / $var:; keys are never inspected. These are all wrong and are passed through to the script unchanged:

{ "db": { "$res": "f/databases/postgres_prod" } }
{ "db": { "resource": "f/databases/postgres_prod" } }
{ "db": "f/databases/postgres_prod" }

The string may sit anywhere a string can — a top-level argument, a nested object field ({ "gh_auth": { "token": "$var:g/all/gh_token" } }), or an array element (array elements are walked only while nested at most two levels deep, and only for arrays of at most 1000 items). The prefix must be on the string itself.

Common Resource Types

PostgreSQL

{
  "resource_type": "postgresql",
  "value": {
    "host": "localhost",
    "port": 5432,
    "user": "postgres",
    "password": "$var:g/all/pg_password",
    "dbname": "windmill",
    "sslmode": "prefer"
  }
}

MySQL

{
  "resource_type": "mysql",
  "value": {
    "host": "localhost",
    "port": 3306,
    "user": "root",
    "password": "$var:g/all/mysql_password",
    "database": "myapp"
  }
}

Slack

{
  "resource_type": "slack",
  "value": {
    "token": "$var:g/all/slack_token"
  }
}

AWS S3

{
  "resource_type": "s3",
  "value": {
    "bucket": "my-bucket",
    "region": "us-east-1",
    "accessKeyId": "$var:g/all/aws_access_key",
    "secretAccessKey": "$var:g/all/aws_secret_key"
  }
}

HTTP/API

{
  "resource_type": "http",
  "value": {
    "baseUrl": "https://api.example.com",
    "headers": {
      "Authorization": "Bearer $var:g/all/api_token"
    }
  }
}

Kafka

{
  "resource_type": "kafka",
  "value": {
    "brokers": "broker1:9092,broker2:9092",
    "sasl_mechanism": "PLAIN",
    "security_protocol": "SASL_SSL",
    "username": "$var:g/all/kafka_user",
    "password": "$var:g/all/kafka_password"
  }
}

NATS

{
  "resource_type": "nats",
  "value": {
    "servers": ["nats://localhost:4222"],
    "user": "$var:g/all/nats_user",
    "password": "$var:g/all/nats_password"
  }
}

MQTT

{
  "resource_type": "mqtt",
  "value": {
    "host": "mqtt.example.com",
    "port": 8883,
    "username": "$var:g/all/mqtt_user",
    "password": "$var:g/all/mqtt_password",
    "tls": true
  }
}

When No Resource Type Fits

The Windmill Hub publishes resource types for most services, and an instance gets them by syncing with the hub. When none fits the service:

• If the instance is reported as not having synced the hub's types, mention that a superadmin can sync them: the hub most likely has one for the service. That holds for a type a hub script takes too: it is missing here until the sync, so say so before asking for a resource of it. Create one of your own only if the user still wants it, since after a sync the workspace would hold both.
• Otherwise, or when the user prefers it to syncing, propose a custom resource type named c_<name> holding the service's connection fields (base URL, account or region identifiers, credentials), as in "Custom Resource Types" below, and ask the user before creating it: every resource of that type and every script taking one depends on its fields.
• A plain variable instead of a resource is fine when the user asks for it; without that, default to the resource, its secret in a variable it references.

Custom Resource Types

A custom type's name starts with c_: the hub's types reach every instance under their plain names, so the prefix keeps a custom type from clashing with one synced later. Scripts and flows refer to the full name: format: resource-c_custom_api, RT.CCustomApi in TypeScript, a c_custom_api TypedDict in Python.

Create custom resource types with JSON Schema:

{
  "name": "c_custom_api",
  "schema": {
    "type": "object",
    "properties": {
      "base_url": {"type": "string", "format": "uri"},
      "api_key": {"type": "string"},
      "timeout": {"type": "integer", "default": 30}
    },
    "required": ["base_url", "api_key"]
  },
  "description": "Custom API connection"
}

Save as: c_custom_api.resource-type.json

OAuth Resources

OAuth resources are managed through the Windmill UI and marked:

{
  "is_oauth": true,
  "account": 123
}

OAuth tokens are automatically refreshed by Windmill.

Using Resources in Scripts

TypeScript (Bun/Deno)

export async function main(db: RT.Postgresql) {
  // db contains the resource values
  const { host, port, user, password, dbname } = db;
}

Python

class postgresql(TypedDict):
    host: str
    port: int
    user: str
    password: str
    dbname: str

def main(db: postgresql):
    # db contains the resource values
    pass

CLI Commands

# List resources
wmill resource list

# List resource types with schemas
wmill resource-type list --schema

# Get specific resource type schema
wmill resource-type get postgresql

# Deploy resources to the workspace — destructive to remote state, so only run when
# the user explicitly asks to deploy/publish/push. Depending on how the repo is wired,
# deploy via `git push` or `wmill sync push` (see the Deploying section in AGENTS.wmill.md).
wmill sync push