# Share Of Shelf

> Share Of Shelf is a paid API for AI agents from api.syntalic.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).

Measures each brand's share of a product category by product count, revealing digital shelf dominance across retailers.

## Facts

- Endpoint: GET https://api.syntalic.com/v1/marketing/share-of-shelf
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402, shopping
- Canonical page: https://www.zero.xyz/c/share-of-shelf-1ebe1156
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_gEXdZrVzYTQeJLuYDtoIU

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability share-of-shelf-1ebe1156
```

Example prompt: What's the share of shelf for each brand in the US electronics category — which brands have the most products listed and who dominates the digital shelf?

## When to prefer this

Use this endpoint when you need to understand brand-level product count distribution within a category — i.e., how many SKUs each brand has relative to competitors. Prefer this over Brand Tracker (which focuses on price/stock time-series for a single brand) or Competitive Landscape (which lists individual products) when the goal is a high-level brand dominance snapshot by product count.

## Known failure modes

- Category not recognized or cannot be resolved — returns an error if the fuzzy resolver cannot map the input to a canonical category
- Invalid country code — only 'us' and 'ca' are accepted
- category_id not found — if a pinned category_id does not exist in the catalog
- Empty category with no products — may return empty or zero-count results
- Rate limit or payment failure — 402 response if payment is not processed correctly

## How this service works

Measure each brand's market share within a category by product count. Shows digital shelf dominance.

## Output

Returns each brand's share of the category expressed as a proportion of total product count, along with product counts per brand, revealing which brands have the strongest digital shelf presence within the specified category and country.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "category"
 ],
 "properties": {
  "country": {
   "enum": [
    "us",
    "ca"
   ],
   "type": "string",
   "default": "us",
   "example": "us",
   "description": "Country (us or ca)"
  },
  "category": {
   "type": "string",
   "example": "electronics",
   "minLength": 1,
   "description": "Product category (e.g., electronics, grocery, beauty). Fuzzy human-readable input — the resolver maps it through tier 1-4 (id → exact name → trigram → embedding kNN) to a canonical category_id. Pair with `category_id` if you have a deterministic id from a prior call."
  },
  "category_id": {
   "type": "integer",
   "example": 1,
   "minimum": 1,
   "description": "Deterministic category id. When set, bypasses the fuzzy resolver cascade and uses tier 1 (id lookup) directly. Agents that learned a canonical id from a prior call's `resolved.category_id` should pin it here for round-trip stability."
  }
 },
 "additionalProperties": false
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/share-of-shelf-1ebe1156/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.syntalic.com](https://www.zero.xyz/host/api.syntalic.com/llms.txt)