Mechanic is a development and ecommerce automation platform for Shopify. :)
This task will monitor the configured collections for updates, and automatically tag all products that each contains. If a configured collection has at least one condition-based source (e.g. metafield contains a specific value), then choose either an hourly or daily scheduled run to pick up the dynamic membership changes which don't trigger collection updates.
Runs Occurs whenever a collection is updated, including when a product is manually added or removed from the collection or when the collection rules change and Occurs when a user manually triggers the task. Configuration includes collections and tags, run hourly, and run daily.
This task will monitor the configured collections for updates, and automatically tag all products that each contains. If a configured collection has at least one condition-based source (e.g. metafield contains a specific value), then choose either an hourly or daily scheduled run to pick up the dynamic membership changes which don't trigger collection updates.
The task will also remove tags from any products if they are no longer in a matching collection. This task may be run manually to process all configured collections if you choose not to use a scheduled run.
NOTE: As of July 2026, Shopify has merged the manual and automated collection models, and this task will now support any configured collection as long as the task API is set to 2026-07 or newer.
Mechanic is designed to benefit everybody: merchants, customers, developers, agencies, Shopifolks, everybody.
That’s why we make it easy to configure automation without code, why we make it easy to tweak the underlying code once tasks are installed, and why we publish it all here for everyone to learn from.
(By the way, have you seen our documentation? Have you joined the Slack community?)
shopify/collections/update
mechanic/user/trigger
{% if options.run_hourly__boolean %}
mechanic/scheduler/hourly
{% elsif options.run_daily__boolean %}
mechanic/scheduler/daily
{% endif %}{% assign collections_and_tags = options.collections_and_tags__keyval_required %}
{% assign collection_keys = collections_and_tags | keys %}
{% assign collections_to_process = array %}
{% if event.topic == "shopify/collections/update" %}
{% comment %}
-- on collection update, make sure this is one of the configured collections
{% endcomment %}
{% assign collection_id = collection.id | append: "" %}
{% for keyval in collections_and_tags %}
{% assign collection_key = keyval[0] %}
{% if collection_key == collection_id
or collection_key == collection.title
or collection_key == collection.handle
%}
{% assign collection_to_process = hash %}
{% assign collection_to_process["id"] = collection.admin_graphql_api_id %}
{% assign collection_to_process["tag"] = keyval[1] %}
{% assign collections_to_process = collections_to_process | push: collection_to_process %}
{% break %}
{% endif %}
{% endfor %}
{% elsif event.topic == "mechanic/user/trigger" or event.topic contains "mechanic/scheduler/" %}
{% comment %}
-- get all collections in the shop (up to 25k) and then filter them by the collection keys
{% endcomment %}
{% assign cursor = nil %}
{% for n in (1..100) %}
{% capture query %}
query {
collections(
first: 250
after: {{ cursor | json }}
) {
pageInfo {
hasNextPage
endCursor
}
nodes {
id
legacyResourceId
title
handle
}
}
}
{% endcapture %}
{% assign result = query | shopify %}
{% for collection in result.data.collections.nodes %}
{% for keyval in collections_and_tags %}
{% assign collection_key = keyval[0] %}
{% if collection_key == collection.legacyResourceId
or collection_key == collection.title
or collection_key == collection.handle
%}
{% assign collection_to_process = hash %}
{% assign collection_to_process["id"] = collection.id %}
{% assign collection_to_process["tag"] = keyval[1] %}
{% assign collections_to_process = collections_to_process | push: collection_to_process | uniq %}
{% break %}
{% endif %}
{% endfor %}
{% endfor %}
{% if result.data.collections.pageInfo.hasNextPage %}
{% assign cursor = result.data.collections.pageInfo.endCursor %}
{% else %}
{% break %}
{% endif %}
{% endfor %}
{% endif %}
{% comment %}
-- add a preview block that satifies all task topics
{% endcomment %}
{% if event.preview %}
{% capture collections_to_process_json %}
[
{
"id": "gid://shopify/Collection/1234567890",
"tag": "sample tag"
}
]
{% endcapture %}
{% assign collections_to_process = collections_to_process_json | parse_json %}
{% endif %}
{% comment %}
-- process the collections and their products
{% endcomment %}
{% for collection_to_process in collections_to_process %}
{% assign collection_id = collection_to_process["id"] %}
{% assign collection_tag = collection_to_process["tag"] %}
{% assign collection_tag_lower = collection_tag | downcase %}
{% comment %}
-- get all of the product IDs currently in the collection (up to 25k)
{% endcomment %}
{% assign cursor = nil %}
{% assign collection_product_ids = array %}
{% for n in (1..100) %}
{% capture query %}
query {
collection(id: {{ collection_id | json }}) {
products(
first: 250
after: {{ cursor | json }}
) {
pageInfo {
hasNextPage
endCursor
}
nodes {
id
}
}
}
}
{% endcapture %}
{% assign result = query | shopify %}
{% if event.preview %}
{% capture result_json %}
{
"data": {
"collection": {
"products": {
"nodes": [
{
"id": "gid://shopify/Product/1234567890"
}
]
}
}
}
}
{% endcapture %}
{% assign result = result_json | parse_json %}
{% endif %}
{% assign collection_product_ids
= result.data.collection.products.nodes
| map: "id"
| concat: collection_product_ids
%}
{% if result.data.collection.products.pageInfo.hasNextPage %}
{% assign cursor = result.data.collection.products.pageInfo.endCursor %}
{% else %}
{% break %}
{% endif %}
{% endfor %}
{% comment %}
-- get IDs for all products with collection tag
{% endcomment %}
{% assign cursor = nil %}
{% assign tagged_product_ids = array %}
{% for n in (1..100) %}
{% capture query %}
query {
products(
first: 250
after: {{ cursor | json }}
query: {{ collection_tag | json | prepend: "tag:" | json }}
) {
pageInfo {
hasNextPage
endCursor
}
nodes {
id
tags
}
}
}
{% endcapture %}
{% assign result = query | shopify %}
{% if event.preview %}
{% capture result_json %}
{
"data": {
"products": {
"nodes": [
{
"id": "gid://shopify/Product/2345678901",
"tags": {{ collection_tag | json }}
}
]
}
}
}
{% endcapture %}
{% assign result = result_json | parse_json %}
{% endif %}
{% comment %}
-- double check that the collection tag exists on each product to avoid occasional query filter quirkiness
{% endcomment %}
{% for product in result.data.products.nodes %}
{% assign product_tags_lower = product.tags | json | downcase | parse_json %}
{% if product_tags_lower contains collection_tag_lower %}
{% assign tagged_product_ids = tagged_product_ids | push: product.id %}
{% endif %}
{% endfor %}
{% if result.data.products.pageInfo.hasNextPage %}
{% assign cursor = result.data.products.pageInfo.endCursor %}
{% else %}
{% break %}
{% endif %}
{% endfor %}
{% comment %}
-- add and remove the collection tag from products
{% endcomment %}
{% for collection_product_id in collection_product_ids %}
{% unless tagged_product_ids contains collection_product_id %}
{% action "shopify" %}
mutation {
tagsAdd(
id: {{ collection_product_id | json }}
tags: {{ collection_tag | json }}
) {
userErrors {
field
message
}
}
}
{% endaction %}
{% endunless %}
{% endfor %}
{% for tagged_product_id in tagged_product_ids %}
{% unless collection_product_ids contains tagged_product_id %}
{% action "shopify" %}
mutation {
tagsRemove(
id: {{ tagged_product_id | json }}
tags: {{ collection_tag | json }}
) {
userErrors {
field
message
}
}
}
{% endaction %}
{% endunless %}
{% endfor %}
{% endfor %}