cathrynlavery/shopify-developer

Shopify Developer

Use this skill as the coordination hub. Keep implementation details in references/ files and load only the file(s) needed for the task.

Authentication

Use quarterly API versions in all endpoints, for example 2026-01.

Admin GraphQL endpoint:

https://${SHOP}.myshopify.com/admin/api/${API_VERSION}/graphql.json

Admin API headers:

X-Shopify-Access-Token: ${SHOPIFY_ACCESS_TOKEN}
Content-Type: application/json

Storefront GraphQL endpoint:

https://${SHOP}.myshopify.com/api/${API_VERSION}/graphql.json

Storefront API headers:

X-Shopify-Storefront-Access-Token: ${SHOPIFY_STOREFRONT_TOKEN}
Content-Type: application/json

Source environment variables from ~/.agents/.env before running commands.

API Conventions

• Prefer GraphQL over REST for new work.
• Include API version in the URL; update quarterly.
• Paginate with cursors (first/after) rather than page numbers.
• Handle both top-level errors and mutation userErrors.
• Budget GraphQL query cost and throttle based on available points.
• Use bulk operations for large export/import workloads.
• Prefer idempotent mutation patterns for retry-safe writes.

Core Workflows

Theme development pipeline:

• Pull current theme state, iterate in local dev, push to draft first.
• Validate theme editor behavior (sections, blocks, settings) before live publish.
• Reference: references/theme-architecture.md, references/liquid.md.

Product and metafield management:

• Define metafield/metaobject schemas first, then write values through Admin API.
• Access values in Liquid and Storefront API using type-safe patterns.
• Reference: references/admin-api.md, references/metafields-metaobjects.md.

Checkout customization:

• Use Checkout UI Extensions and Shopify Functions; avoid legacy checkout patterns.
• Separate UI concerns (extensions) from pricing/fulfillment logic (functions).
• Reference: references/checkout-extensibility.md, references/shopify-functions.md.

Reference Files

| File | When to read | |---|---| | references/admin-api.md | Product/order/customer/inventory GraphQL workflows; bulk operations. Grep hint: bulkOperation. | | references/storefront-api.md | Headless storefront queries, cart operations, customer account flows, localization. Grep hint: cart. | | references/metafields-metaobjects.md | Metafield types, definitions, Liquid access, metaobject CRUD. Grep hint: metafieldsSet. | | references/liquid.md | Liquid objects, filters, tags, render patterns, metafield rendering, performance tuning. | | references/theme-architecture.md | OS 2.0 structure, section schema, templates, app blocks, CLI deployment flow. | | references/checkout-extensibility.md | Checkout UI extensions, web pixels, migration timelines, post-purchase extensions. | | references/shopify-functions.md | Function types, WASM constraints, implementation/testing, Scripts migration path. | | references/webhooks-events.md | Webhook topics, compliance webhooks, HMAC verification, retries/idempotency. | | references/platform-limits.md | API versioning, limits, deprecation timelines, plan-specific capabilities. |

Gotchas

1. Use .value when rendering metafields in Liquid.
2. Use metafieldsDelete (plural), not singular deletion mutation names.
3. Do not rely on checkout.liquid; migrate to checkout extensibility.
4. Plan Scripts migration before June 30, 2026 sunset.
5. Treat REST Admin API as maintenance-only for new implementation.
6. Rotate to supported API versions before the 12-month support window ends.
7. Implement idempotency keys for retry-safe writes before April 1, 2026 enforcement.
8. Remove deprecated Storefront tax fields during API upgrades.
9. Do not hand-edit config/settings_data.json; use Theme Editor.
10. Keep Shopify Functions logic minimal to stay inside strict runtime limits.