Subreddit Monitor — New Post Alerts (Vigia)

Monitor a whole subreddit and get only NEW posts since last check, with a discussion-velocity spike signal. Charged only on new posts, never per run. Ideal for community-management, trend-tracking and social-listening agents.

Free tier — 10 results free on every run

The first 10 results of every run are free, on every run you ever make — not a one-off trial. Run it on your own subjects and see the real output before you are billed for a single result.

One guard: the free allowance never covers more than half of a run, so a run returning 6 results gets 3 free. That keeps the offer sustainable.

What it does

Watch a whole subreddit for new posts and a discussion spike. You get only what changed since your last check — never a full re-dump to diff yourself.

Why Vigia — 5 advantages a raw scraper can't match

1. You pay the alert price only for real change. New-post alerts are billed only for genuinely new posts since your last check. A quiet run bills just the small source-check fee (the cost of looking) — never the alert price on unchanged data. Raw scrapers bill every row of a full re-scan every run.
2. Never billed on a failed source. The source check is charged only when the source actually responded. If it's down, you don't pay for our outage.
3. Append-only delta + spike signal. The first monitored run stores a free baseline; later runs deliver only what's new, plus a velocity-spike alert when volume suddenly surges (trend / review-bomb / hiring-surge).
4. Hard cost cap you control. Set maxTotalChargeUsd and the run can never bill above it — predictable spend, no surprise invoice.
5. Agent-ready output. Clean, normalized rows and a RUN_SUMMARY.json with ready-to-use signals — chainable from any MCP / A2A agent in one step.

Example input

{
  "subreddits": [
    "SaaS",
    "startups"
  ],
  "monitorEnabled": true,
  "maxTotalChargeUsd": 1.0
}

Set monitorEnabled: true so the first run stores a free baseline and later runs return only new results. Pin a monitorId to keep separate targets from sharing state.

Output

Each row is a normalized change record: record_id, query_id, title, url, author, published_at, score, text. A RUN_SUMMARY.json accompanies every run with the aggregated signal (counts, velocity spikes, trend).

How you're charged

• Post alert — billed once per new post since the last check (this is the only charge that scales with change).
• Source check ($0.10) — billed once per monitored target per run, only when the source responded. A failed source is free.
• A quiet run bills only the source check ($0.10), never the alert price. Vigia never scrapes the source itself; it chains a licensed scraper, caps every call, and passes you only the delta.

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Part of the Vigia monitoring suite — change-only billing, outage-safe, agent-ready.

Related scrapers

Same data, other sources — all with the same free tier, the same clean schema and the same pay-only-for-what-you-get billing:

Actor
Reddit Search Scraper - Posts & Mentions by Keyword
Hacker News Scraper - Posts & Comments by Keyword
Stack Overflow Scraper - Questions by Tag or Keyword
Google News Scraper - Articles by Keyword or Topic
X (Twitter) Search Scraper - Posts by Keyword
Company Careers & ATS Jobs API - Workday, Greenhouse