Getting Started

Get your first App Store API call working in under two minutes.

1. Get your API key

Sign up for a FetchLayer account and generate an API key from the dashboard. Free tier included — no credit card required.

Create free account →

2. Make your first request

Search for an app by name, or fetch reviews by app ID.

Search for an app

bash

curl -X POST https://api.fetchlayer.dev/appstore/search \
  -H "Authorization: Bearer ss-your-key" \
  -H "Content-Type: application/json" \
  -d '{"query":"notion","country":"us"}'

Fetch app reviews

bash

curl -X POST https://api.fetchlayer.dev/appstore/reviews \
  -H "Authorization: Bearer ss-your-key" \
  -H "Content-Type: application/json" \
  -d '{"appId":"1232780281","country":"us","pages":1}'

Tip

The country parameter changes both the storefront and the language of returned reviews — use it to check localization or pricing across regions.

Tip

Pass since (an ISO 8601 date, e.g. 2026-01-31) to only get reviews from that date forward. With the default sort=recent, pagination also stops as soon as it passes the cutoff — so a narrow date window is billed for far fewer pages than pages alone requests. That saving doesn't apply with sort=helpful, since Apple's feed isn't date-ordered there.

3. Understand the response

Every endpoint returns structured JSON. Search returns app listings with ratings and metadata. Reviews returns customer feedback with ratings and text.

json

{
  "results": [
    {
      "appId": "1232780281",
      "name": "Notion: Notes, Tasks, AI",
      "subtitle": "Plan, organize, track projects",
      "rating": null,
      "ratingCount": null,
      "editorsChoice": true
    }
  ]
}

Next steps

Error responses

Every error, on every route, is JSON in one shape: error (what went wrong, in words), status, code, retryable and requestId, which also comes as the X-Request-Id header. Branch on code and retryable rather than on the text; on a 5xx the text is generic. Quote requestId when reporting a problem.

json

{
  "error": "Missing required parameter: url",
  "status": 400,
  "missing": ["url"],
  "code": "invalid_input",
  "retryable": false,
  "requestId": "922874e3-c0d0-40d8-8866-d198af132420"
}

code	Status	Retryable	Meaning
invalid_input	400	no	The request needs fixing; error names the field. A missing required parameter also lists it in missing.
unauthorized	401	no	The API key is missing or not valid.
insufficient_credits	402	no	Nothing left to spend: no credits, a used-up free trial, or a monthly allowance and credit balance both spent. error says which. Waiting does not help; topping up does.
forbidden	403	no	This key or account is not allowed this request.
not_found	404	no	What the request names does not exist or is not public.
expired	410	no	What the request refers to is no longer available; ask for it afresh.
quota_exceeded	429	no	A request-rate limit was reached; error says which. Slow down before sending more.
cancelled	499	no	The caller closed or cancelled the request before it finished. The work was stopped and nothing was charged.
time_limit	503	yes	Your timeoutMs ran out before there was anything to return; ask again, or allow more time.
temporarily_unavailable	503	yes	Not available right now; ask again shortly.
posts_unavailable	403	no	TikTok user videos: TikTok is not showing this account’s posts publicly right now. Asking again at once returns the same answer; nothing is charged.
store_unreachable	503	yes	Store routes (Shopify, WooCommerce): the store itself can’t be reached right now — it may be offline. Ask again later. Where a store route doesn’t say so yet, an offline store is temporarily_unavailable.
upstream_error	502	yes	The source answered in a way that could not be used; ask again later.
internal_error	500	yes	Something failed on our side; ask again later, and quote requestId if it persists.
tool_error	—	no	MCP only: a tool call failed in a way no other code describes; error says what.

More codes may be added; treat one you do not recognise by its retryable flag. Over MCP, a tool error carries the same fields in structuredContent, and as a JSON text block beside the message.

Product overviewApp Store API: what it returns, pricing and use cases

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