# API Direct – Get Substack Note by URL or ID

> API Direct – Get Substack Note by URL or ID 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).

Fetches a single Substack note (short-form post) along with its replies, given a note URL or numeric note ID, with optional AI emotion analysis.

## Facts

- Endpoint: GET https://x402.apidirect.io/v1/substack/note?utm_source=zero.xyz
- Price: $0.004/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-30
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/api-direct-get-substack-note-by-url-or-id-fcab9bec
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_gxhOMUR7i0C44kT9ehOmG

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 api-direct-get-substack-note-by-url-or-id-fcab9bec
```

Example prompt: Can you pull up this Substack note for me — https://substack.com/@hamish/note/c-355659691 — and include all the replies? Also run the emotion analysis on it so I can see the sentiment.

## When to prefer this

Use this endpoint when you need the full content and reply thread of a specific Substack note identified by URL or ID. Prefer this over Substack search endpoints when you already have the note's URL or numeric ID and want structured data including replies. Choose the sentiment option when you need emotion analysis without a separate NLP call.

## Known failure modes

- Note URL or ID not found — returns 404 or empty result
- Invalid URL format — returns validation error
- Note has been deleted or made private — returns error or empty content
- Rate limit exceeded — returns 429
- Payment not attached or insufficient — returns 402

## How this service works

Get a Substack Note by URL or ID, with its replies.

## Output

Returns the Substack note's content (text, author, timestamp, engagement counts) along with its reply thread. If get_sentiment is enabled, each item also includes Plutchik's Wheel emotion scores, the dominant emotion, intensity level, and polarity (positive/negative/neutral).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [],
     "properties": {
      "url": {
       "type": "string",
       "maxLength": 500,
       "description": "Note URL, e.g. https://substack.com/@hamish/note/c-355659691 (max 500 characters). Provide either url or note_id."
      },
      "note_id": {
       "type": "string",
       "description": "Numeric note ID, with or without the c- prefix. Provide either url or note_id."
      },
      "get_sentiment": {
       "type": "boolean",
       "default": false,
       "description": "Set to true to add AI emotion analysis (Plutchik's Wheel) to each result. Adds +$0.001 per request to the cost. Returns emotion scores, dominant emotion, intensity, and polarity."
      }
     }
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/api-direct-get-substack-note-by-url-or-id-fcab9bec/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.apidirect.io](https://www.zero.xyz/host/x402.apidirect.io/llms.txt)