Walmart Search API

Please help me write a data collection script with the EveryInfra Walmart Search endpoint (walmart/search).

Endpoint contract:
- Request: POST https://api.everyinfra.com/api/v1/social with the header Authorization: Bearer <API key>. Read the key from the EVERYINFRA_API_KEY environment variable and never hard-code it.
- In the request body, set platform to walmart and action to search, and put the parameters inside params.
- Required parameters:
  - keyword: Specifies the product search term for the search action. The search targets the US Walmart storefront and fetches a single page of results. It does not search store locations or product reviews.
- Optional parameters:
  - lang: Sets the display language for the search and profile actions. Allowed values are en (English, default) and fr (French). This parameter changes only the interface language, not the storefront region or review filtering. (allowed: en / fr)
  - limit: The most rows to return in this call, an integer of 1 or more. The default applies when you leave it out, and a call can return fewer rows.
- Returns a list of records. Main fields of each record: item_id, name, url, brand, price, was_price, currency, rating, rating_scale, review_count, in_stock, availability; 17 fields in total, full list at https://api.everyinfra.com/api/v1/social/catalog?platform=walmart.
- Example request body:
{
  "platform": "walmart",
  "action": "search",
  "params": {
    "keyword": "air purifier"
  }
}
- Price: $1.39 per 1,000 requests; failed and empty results are not charged.
- For dozens or hundreds of targets, add "mode": "async" to the body: you get a job_id at once and poll GET https://api.everyinfra.com/api/v1/jobs/{job_id} for the result.
- On 422, fix the request using the suggested parameter names and allowed values in the error; on 429 or 503, wait for Retry-After and try again.

Before writing code, ask me which targets I need, how many, which fields, and what output format I want; then confirm the plan and the rough cost with me.