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API Direct – Substack Publication Posts
x402
API Direct – Substack Publication Posts is a paid API for AI agents from x402.apidirect.io, paid per call via x402, $0.004/call, status unknown (last checked 2026-10-30).
Retrieve a Substack publication's posts sorted by newest, top, or most discussed, or search them by keyword — with optional AI sentiment analysis.
Price / call$0.004
Success—
StatusUnknown
How this service works
Get a publication's posts, newest first, top or most discussed, or search them by keyword.
Output
A paginated list of up to 20 posts from the specified Substack publication, including post titles, dates, and metadata. When searching by keyword, results are ranked by relevance. When sort_by is used, results are ordered by most_recent, top, or discussions. If get_sentiment is true, each post also includes Plutchik's Wheel emotion scores, the dominant emotion, intensity level, and polarity (positive/negative).
Example use cases
Newsletter research by keyword
“Search Lenny's Substack (lenny.substack.com) for all posts mentioning 'growth loops' and show me the most relevant ones.”
Track a writer's latest output
“Pull the 20 newest posts from the 'Stratechery' Substack publication so I can see what Ben Thompson has been writing about recently.”
Podcast episode archive browsing
“Get me only the podcast episodes from 'The Diff' newsletter on Substack, sorted by most recent, starting from page 1.”
Technical details
Endpoint
GEThttps://x402.apidirect.io/v1/substack/publication/posts?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need to browse, search, or monitor posts from a specific known Substack publication — particularly when you want keyword search, sorting by engagement or recency, or optional AI emotion scoring on results. Prefer this over the trending Substack endpoint when you have a target publication in mind rather than wanting cross-platform trending content.
Side effects
- Invalid or unresolvable publication subdomain returns an error or empty result
- Keyword query exceeding 500 characters is rejected
- Requesting sort_by with a keyword query is ignored (relevance overrides sort)
- Page number beyond available archive returns empty results
- Publication with no posts or a private/paywalled archive may return empty or partial results
- Network timeouts or Substack rate limiting may cause request failures
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object |
Tags
x402
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