Shopify Competitor Price & Stock Monitor

Track competitor pricing and product availability for ecommerce research, pricing intelligence and catalog monitoring. Add public Shopify stores and get structured snapshots plus changes between runs.

Monitors one or more public Shopify stores via their /products.json endpoint and emits deterministic change events between runs.

Input

Field	Type	Default	Notes
storeDomains	string[]	— (required)	shop.com, https://shop.com, or shop.myshopify.com. Non-http(s) schemes, IP literals and localhost are rejected. Duplicates are collapsed.
maxProductsPerStore	integer	2000	Distinct-product cap per store.
maxPagesPerStore	integer	20	/products.json page cap (page size 250).
requestTimeoutSecs	integer	30	Per-request timeout.
concurrency	integer	3	Stores fetched in parallel.
minRequestDelayMs	integer	500	Client-side rate limit between paginated requests.
maxResponseBytes	integer	5000000	Byte ceiling per response.
emitSnapshotRows	boolean	true	Also write the current variant-level catalog to the dataset.
resetSnapshot	boolean	false	Ignore the stored snapshot; treat as a fresh baseline.

How comparison works

Each run fetches the current catalog, loads the previous snapshot from the key-value store (SNAPSHOT-<domain>), diffs them deterministically, writes the new snapshot, and appends events to the dataset.

• First run for a domain (or resetSnapshot) establishes the baseline and emits no change events (firstRun: true in the summary).
• Event types: new_product, removed_product (a product id appeared / disappeared); price_changed (a shared variant's price, compare-at price or SKU moved, or a new variant appeared under an existing product with before: null); availability_changed (a shared variant's available flag flipped, or a variant disappeared from a surviving product with after.removed: true).
• Events are fully sorted (type → productId → variantId) so re-running on unchanged data produces byte-identical output.

Resilience

• A request failure stops pagination for that store, is counted in requestFailures / failuresByReason, and never throws.
• If every page fails (pagesFetched === 0) the stored snapshot is left untouched and no events are emitted — a network blip never looks like "all products removed".
• If a previously populated store (> 5 products) suddenly returns an empty catalog, the run flags suspicious-empty-catalog and refuses to overwrite the snapshot.
• One failing store never affects the others (bounded-concurrency, per-store isolation).

Output

type: "change" and type: "snapshot" rows — see .actor/dataset_schema.json. A SUMMARY record with per-domain reports, totals, changeCounts and failuresByReason is written to the key-value store.

Safety

Only the public /products.json endpoint is used — no admin API, no tokens, no private data. All requests go through the shared safeFetchJson (https upgrade, DNS checked against private ranges, manual redirects, JSON content-type allow-list, byte ceiling, timeout cleared in finally).

Known limitations

• Stores that disable /products.json, sit behind Cloudflare bot protection, or are not Shopify will yield catalog-fetch-failed / an empty parse rather than data. This is reported, not fatal.
• available reflects the storefront available flag, not real-time inventory counts (Shopify does not expose those publicly).

Commands

npm ci                                                  # monorepo root
npm run check -w shopify-competitor-price-stock-monitor
npm run smoke -w shopify-competitor-price-stock-monitor  # offline, two-run diff
npx apify validate-schema

Deployment

Not deployed here. apify push is intentionally not run — the lead engineer handles deployment.