Reddit Posts by user API

Please help me write a data collection script with the EveryInfra Reddit Posts by user endpoint (reddit/user_posts).

How the endpoint works:
- 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 reddit and action to user_posts, and put the parameters inside params.
- Required parameters:
  - username: Specifies the username or full /user/username/ URL for user_posts. For usernames that start with u, pass the full URL and check the result. user_comments also takes the username, u/username or a profile URL.
- Optional parameters:
  - date_range: Filters posts by time range for subreddit and user listings. Allowed values are all_time, past_hour, past_day, past_week, past_month, and past_year. (allowed: all_time / past_day / past_hour / past_month / past_week / past_year)
  - sort: Orders Reddit post listings by newest, popular, relevance, rising, or top. The post_detail and comments actions do not accept sort. (allowed: newest / popular / relevance / rising / top)
  - limit: The most rows to return in this call, an integer from 1 to 50. The default applies when you leave it out, and a call can return fewer rows. Larger values return 422 before any charge. (default: 10)
- Returns a list of records. Main fields of each record: id, url, title, text, author_username, community, like_count, comment_count, posted_at, flair, domain, external_link; 14 fields in total, full list at https://api.everyinfra.com/api/v1/social/catalog?platform=reddit.
- Example request body:
{
  "platform": "reddit",
  "action": "user_posts",
  "params": {
    "username": "spez"
  }
}
- Price: $0.56 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.