Agent Skills: Windmill Triggers

Windmill Triggers

Triggers allow external events to invoke your scripts and flows.

File Naming

Trigger configuration files use the pattern: {path}.{trigger_type}_trigger.yaml

Examples:

• u/user/webhook.http_trigger.yaml
• f/data/kafka_consumer.kafka_trigger.yaml
• f/sync/postgres_cdc.postgres_trigger.yaml
• f/inbound/orders.email_trigger.yaml

Email Triggers

An email trigger routes incoming emails to a script or flow. Each trigger reserves a local-part: emails sent to <local_part>@<windmill_email_domain> are delivered to the configured runnable. Set workspaced_local_part: true to namespace it per workspace (the actual recipient becomes <workspace_id>-<local_part>@…); on Windmill Cloud this is required.

Senders may append URL-style extras to the local-part with +: mytrigger+foo=bar+baz=qux@…. They flow through to the script as email_extra_args (see below).

Payload

The runnable receives:

• parsed_email — { headers, text_body, html_body, attachments[] }. Each attachment has { headers, body }.
• raw_email — the raw RFC 822 message as a string, or an S3 object ({ s3: "windmill_emails/<job_id>/raw.eml" }) if the message exceeds 1 MiB.
• email_extra_args (optional, only when sender appended +key=value extras) — a flat object of the parsed extras.

With a preprocessor, all of the above are nested under event along with event.kind = "email" and event.trigger_path (the trigger's path). Without a preprocessor, trigger_path is not exposed — add a preprocessor if you need it.

Attachments are S3 objects

Binary attachments are uploaded to the workspace S3 bucket and surface in parsed_email.attachments[i].body as:

{ "s3": "windmill_emails/<job_id>/attachments/<filename>" }

To read the bytes inside a script, use the wmill SDK:

// TypeScript
import * as wmill from "windmill-client"
const file = await wmill.loadS3File(parsed_email.attachments[0].body)

# Python
import wmill
data = wmill.load_s3_file(parsed_email["attachments"][0]["body"])

If the workspace has no S3 resource configured (Workspace Settings → Object storage), body falls back to the string "configure s3 in the workspace settings to handle attachments". The same applies to large raw_email bodies. Email attachment storage requires the server to be built with the parquet feature.

Text/HTML/inline parts are placed inline in body as strings.

CLI Commands

After writing, tell the user they can run these commands (do NOT run them yourself):

# Push trigger configuration
wmill sync push

# Pull triggers from Windmill
wmill sync pull