# Substack Posts Tracker (`gochujang/substack-posts-tracker`) Actor

Fetch posts from any Substack publication: title, author, subtitle, publication date, word count, estimated reading time, tags, and post URL. Supports multiple newsletters, keyword filtering, and date range. Uses Substack's public API. No auth needed.

- **URL**: https://apify.com/gochujang/substack-posts-tracker.md
- **Developed by:** [Hojun Lee](https://apify.com/gochujang) (community)
- **Categories:** News
- **Stats:** 1 total users, 0 monthly users, 0.0% runs succeeded, 0 bookmarks
- **User rating**: No ratings yet

## Pricing

from $1.00 / 1,000 item trackeds

This Actor is paid per event. You are not charged for the Apify platform usage, but only a fixed price for specific events.

Learn more: https://docs.apify.com/actors/running/actors-in-store.md#pay-per-event

## What's an Apify Actor?

An Actor is a serverless cloud program that runs on the Apify platform. It has two run modes.
In Batch mode, an Actor accepts a well-defined JSON input, performs an action which can take anything from a few seconds to a few hours,
and optionally produces a well-defined JSON output, datasets with results, or files in key-value store.
In Standby mode, an Actor provides a web server which can be used as a website, API, or an MCP server.

Apify vocabulary and the platform model are defined once, in the agent quickstart at https://apify.com/agents.md.

## How to integrate an Actor?

If asked about integration, you help developers integrate Actors into their projects.
You adapt to their stack and deliver integrations that are safe, well-documented, and production-ready.

Do not guess an integration path. Every one of them is in the agent quickstart at https://apify.com/agents.md: the Apify MCP server, Agent Skills with the Apify CLI, the JavaScript and Python clients, the REST API, and the account-free path for an agent with no human to sign in. It also carries the rule on stating cost before the first paid run.

For examples already wired to this Actor's own input schema, see the [API](#api) section below.

Each client library has reference documentation the quickstart does not restate: [JavaScript/TypeScript](https://docs.apify.com/api/client/js/docs.md) (`npm install apify-client`) and [Python](https://docs.apify.com/api/client/python/docs.md) (`pip install apify-client`).

# README

## Substack Posts Tracker

**Substack Posts Tracker** fetches posts from any Substack newsletter — returning title, subtitle, publication date, word count, reading time, reactions, comments, and post URL. Supports multiple publications, keyword filtering, date range, and free-only mode. Substack's public API, no authentication required. $0.002/post.

Substack has become the primary publishing platform for independent analysis in crypto, tech, finance, and politics. The best alpha and insight lives in newsletters that don't have RSS readers. This actor makes any Substack programmatically accessible for research, monitoring, and content pipelines.

***

### Why use Substack Posts Tracker?

1. **Research and analysis pipeline** — Track the most-cited newsletters in your domain. High-reaction posts from top writers often precede mainstream coverage of emerging ideas.
2. **Investment research reading list** — Monitor crypto/finance newsletters (e.g. Bankless, Delphi Digital, The Block) for new posts and route them to your reading workflow automatically.
3. **Content curation for newsletters** — Pull top-performing posts (`reactions_count` descending) from multiple publications to curate weekly roundups.
4. **Competitive intelligence** — Monitor how competitors are positioning their content and what topics get the most engagement in your niche.
5. **Academic and media research** — Track publication frequency, word count trends, and topic evolution for specific writers over time.

***

### How to use

1. Open the actor on Apify Store and click **Try for free**.
2. Set `publications` to a list of Substack subdomains or custom domains (e.g. `["gwern.substack.com", "stratechery.com"]`).
3. Set `keyword` to filter to specific topics, or leave blank for all posts.
4. Set `since` to limit to recent posts only.
5. Click **Start**. Returns structured post records from each publication.

***

### Input

| Field | Type | Default | Description |
|-------|------|---------|-------------|
| `publications` | string\[] | *required* | Substack URLs or subdomains (e.g. `"gwern.substack.com"`, `"stratechery.com"`) |
| `maxPostsPerPublication` | integer | `25` | Max posts per newsletter (1–500) |
| `keyword` | string | — | Filter by keyword in title or subtitle (case-insensitive) |
| `freeOnly` | boolean | `true` | Skip paywalled posts (only return publicly accessible content) |
| `since` | string | — | ISO 8601 date cutoff — skip posts older than this (e.g. `"2024-01-01"`) |

***

### Output

```json
{
  "publication": "Gwern's Newsletter",
  "publication_url": "https://gwern.substack.com",
  "id": 123456,
  "title": "GPT-4 Capability Overview",
  "subtitle": "A deep dive into what GPT-4 can and cannot do",
  "slug": "gpt-4-capability-overview",
  "url": "https://gwern.substack.com/p/gpt-4-capability-overview",
  "type": "newsletter",
  "audience": "everyone",
  "post_date": "2024-03-15T12:00:00.000Z",
  "word_count": 4200,
  "reading_time_minutes": 21,
  "reactions_count": 312,
  "comments_count": 47,
  "cover_image": "https://substackcdn.com/..."
}
```

#### Key output fields

| Field | Type | Description |
|-------|------|-------------|
| `type` | string | `newsletter`, `podcast`, or `thread` |
| `audience` | string | `everyone` (free), `public`, or `paid` (paywalled) |
| `word_count` | integer | Full word count of the post |
| `reading_time_minutes` | integer | Estimated at 200 words per minute |
| `reactions_count` | integer | Total likes/emoji reactions |
| `comments_count` | integer | Total comments |

***

### Cost estimation

**Pay-Per-Event: $0.005 actor start + $0.002 per post returned.**

| Use case | Posts | Estimated cost |
|----------|-------|----------------|
| 25 posts from 1 newsletter | 25 | ~$0.055/run |
| 100 posts from 3 newsletters | 100 | ~$0.205/run |
| Weekly monitoring (50 new posts) | 50 | ~$0.105/week |
| 500 posts from 5 newsletters | 500 | ~$1.005/run |

***

### FAQ

**Does it work with custom domains (not .substack.com)?**
Yes — custom domains like `stratechery.com` or `mattstoller.substack.com` are supported. Enter the primary domain and the actor resolves the Substack API endpoint automatically.

**Can I get the full post content (body text)?**
The actor returns metadata, title, subtitle, and audience type. Full post body is only accessible from the post URL itself (and may be paywalled for `paid` audience posts).

**What does `freeOnly: true` do?**
When enabled (default), the actor skips posts with `audience: "paid"` — only publicly accessible posts are returned. Set to `false` to see all post metadata including paywalled titles (body still won't be accessible without a subscription).

**Does it support multiple publications at once?**
Yes — pass multiple subdomains in `publications`. Requests run 3 concurrent publications at a time with rate-limit backoff.

***

### Related actors

- [Tech News Aggregator](https://apify.com/gochujang/tech-news-aggregator) — Aggregate news from 6 tech publications alongside Substack newsletters
- [Reddit Subreddit Tracker](https://apify.com/gochujang/reddit-subreddit-tracker) — Reddit community discussion to complement newsletter analysis
- [Crypto News Sentiment Analyzer](https://apify.com/gochujang/crypto-news-sentiment) — AI sentiment scoring for crypto-focused newsletter content

### Feedback

If this actor is useful, a quick review helps others find it: [Leave a review on Apify Store](https://apify.com/gochujang/substack-posts-tracker#reviews)

# Actor input Schema

## `publications` (type: `array`):

Substack publication URLs or subdomains (e.g. 'gwern.substack.com' or 'stratechery.com')

## `maxPostsPerPublication` (type: `integer`):

Maximum number of posts to fetch per publication

## `keyword` (type: `string`):

Only return posts whose title or subtitle contains this keyword (case-insensitive)

## `freeOnly` (type: `boolean`):

Only return publicly accessible free posts

## `since` (type: `string`):

Only return posts published after this date (ISO 8601, e.g. 2024-01-01)

## Actor input object example

```json
{
  "maxPostsPerPublication": 25,
  "freeOnly": true
}
```

# Actor output Schema

## `results` (type: `string`):

No description

# API

You can run this Actor programmatically using our API. Below are code examples in JavaScript, Python, and CLI, as well as the OpenAPI specification and MCP server setup.

## JavaScript example

```javascript
import { ApifyClient } from 'apify-client';

// Initialize the ApifyClient with your Apify API token
// Replace the '<YOUR_API_TOKEN>' with your token
const client = new ApifyClient({
    token: '<YOUR_API_TOKEN>',
});

// Prepare Actor input
const input = {};

// Run the Actor and wait for it to finish
const run = await client.actor("gochujang/substack-posts-tracker").call(input);

// Fetch and print Actor results from the run's dataset (if any)
console.log('Results from dataset');
console.log(`💾 Check your data here: https://console.apify.com/storage/datasets/${run.defaultDatasetId}`);
const { items } = await client.dataset(run.defaultDatasetId).listItems();
items.forEach((item) => {
    console.dir(item);
});

// 📚 Want to learn more 📖? Go to → https://docs.apify.com/api/client/js/docs

```

## Python example

```python
from apify_client import ApifyClient

# Initialize the ApifyClient with your Apify API token
# Replace '<YOUR_API_TOKEN>' with your token.
client = ApifyClient("<YOUR_API_TOKEN>")

# Prepare the Actor input
run_input = {}

# Run the Actor and wait for it to finish
run = client.actor("gochujang/substack-posts-tracker").call(run_input=run_input)

# Fetch and print Actor results from the run's dataset (if there are any)
print(f"💾 Check your data here: https://console.apify.com/storage/datasets/{run.default_dataset_id}")
for item in client.dataset(run.default_dataset_id).iterate_items():
    print(item)

# 📚 Want to learn more 📖? Go to → https://docs.apify.com/api/client/python/docs/quick-start

```

## CLI example

```bash
echo '{}' |
apify call gochujang/substack-posts-tracker --silent --output-dataset

```

## MCP server setup

```json
{
    "mcpServers": {
        "apify": {
            "type": "http",
            "url": "https://mcp.apify.com/?tools=fetch-actor-details,gochujang/substack-posts-tracker"
        }
    }
}
```

The hosted server signs you in with OAuth on first connect, so no API token belongs in this config. Clients without OAuth support can send an `Authorization: Bearer <APIFY_API_TOKEN>` header instead, using a token from API & Integrations in Apify Console (https://console.apify.com/settings/integrations).

## OpenAPI specification

Download the OpenAPI definition: https://api.apify.com/v2/actors/MLm2q1Oq7WSr27Nk8/builds/dusDtHhdyTsHZ9dVi/openapi.json