# Newsletter Sponsor Finder: Substack Sponsors & Ad Leads (`matidepa22/newsletter-sponsor-finder`) Actor

Find Substack newsletters in any niche that sell sponsorships. Get subscribers, posting cadence, engagement and the brands already sponsoring them: ready-made leads for newsletter advertising and sponsorship sales.

- **URL**: https://apify.com/matidepa22/newsletter-sponsor-finder.md
- **Developed by:** [Matias De Pascuale](https://apify.com/matidepa22) (community)
- **Categories:** Marketing, Lead generation, News
- **Stats:** 2 total users, 1 monthly users, 0.0% runs succeeded, 0 bookmarks
- **User rating**: No ratings yet

## Pricing

from $20.00 / 1,000 newsletter analyzeds

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

## Newsletter Sponsor Finder — Substack newsletters that take sponsors

Looking for newsletters to advertise in? Give this Actor a topic ("fintech", "AI", "marketing") or a Substack category, and it returns **newsletters in that niche that actually run sponsors** — with audience size, posting cadence, engagement and **the brands that already sponsored them**.

It reads each newsletter's recent posts and detects sponsor blocks ("Brought to you by…", "Sponsored by…", "Today's sponsor…"), so you only get newsletters with proven sponsorship activity.

### Who it's for

- **Brands & growth teams** — build a media list of newsletters your audience reads, prioritized by size and sponsorship history.
- **Agencies & media buyers** — see which newsletters competitors sponsor and how often.
- **Newsletter writers** — find brands that sponsor newsletters like yours: warm leads for your own sponsorship sales.

### Example

`keywords: ["AI"]`, `categories: ["Technology"]`, 15 newsletters (September 2026):

| Newsletter | Subscribers | Sponsored posts | Recent sponsors |
|---|---|---|---|
| The Pragmatic Engineer | 1,100,000 | 3 of 10 | turbopuffer, Antithesis, Linear, WorkOS |
| Product Growth | 241,000 | 5 of 10 | Arize, Bolt, Product Faculty |
| Latent.Space | 202,000 | 1 of 10 | Supabase |
| Engineering Leadership | 197,000 | 5 of 10 | Unblocked, Hygraph, DX |
| Last Week in AI | 184,000 | 5 of 10 | ODSC, Langfuse |
| Ben's Bites | 171,000 | 1 of 10 | Google Cloud |
| Elena's Growth Scoop | 99,000 | 4 of 10 | Firecrawl, Chargebee, Optimizely, Amplitude |

The run took about 2 minutes and scanned 116 newsletters to find 15 with sponsors.

### Input

```json
{
  "keywords": ["fintech", "payments"],
  "categories": ["Finance"],
  "maxNewsletters": 30,
  "onlyWithSponsors": true,
  "minSubscribers": 1000,
  "postsPerNewsletter": 10,
  "language": "en"
}
```

- **keywords** search Substack for newsletters writing about each topic.
- **categories** browse Substack's own categories (Technology, Business, Finance, Crypto, Health & Wellness…), most popular first.
- **onlyWithSponsors** (default on) returns only newsletters with at least one sponsored post among those scanned. Turn it off to get every newsletter in the niche with its stats.

### Output

One row per newsletter:

```json
{
  "name": "Elena's Growth Scoop",
  "url": "https://www.elenaverna.com",
  "author": "Elena Verna",
  "authorProfileUrl": "https://substack.com/@plgrowth",
  "subscribers": 99000,
  "subscribersLabel": "Tens of thousands of subscribers",
  "paidSubscriptions": true,
  "postsScanned": 10,
  "sponsoredPosts": 4,
  "sponsoredShare": 0.4,
  "sponsors": [
    {
      "name": "Firecrawl",
      "domain": "firecrawl.dev",
      "posts": 2
    },
    {
      "name": "Chargebee",
      "domain": "chargebee.com",
      "posts": 1
    }
  ],
  "lastSponsoredPostDate": "2026-09-24T17:58:00.785Z",
  "postsPerMonth": 2.4,
  "avgReactions": 354,
  "avgComments": 29
}
```

The **`SUMMARY` record** adds a **sponsor leaderboard**: every brand found, ranked by how many newsletters in your niche it sponsors. It's a quick map of who buys newsletter ads in that market.

### Pricing

**$0.02 per newsletter returned.** Newsletters scanned but filtered out (no sponsors, too small) are not charged. Set a maximum cost per run and the Actor stops before exceeding it.

### Good to know

- **Coverage:** Substack newsletters only, including those on custom domains. Newsletters on beehiiv, Ghost or ConvertKit aren't included.
- **Detection:** sponsor blocks with a link are detected reliably. Sponsors mentioned only in plain text can be missed, and occasionally a cross-promotion with another newsletter is counted as a sponsor.
- **Niche size:** in smaller niches only a fraction of newsletters run sponsors, so the Actor may return fewer than `maxNewsletters` after scanning up to 10× that many.
- **Subscriber counts** are the public figures Substack shows; some newsletters hide theirs.
- No contact emails are returned. Use the newsletter URL or the author's Substack profile to reach out.

Need post-level data for specific newsletters instead? See [Substack Scraper & Newsletter Sponsor Finder](https://apify.com/matidepa22/substack-scraper).

# Actor input Schema

## `keywords` (type: `array`):

Topics to search on Substack, e.g. fintech, AI, marketing, crypto. Each keyword finds newsletters writing about it.

## `categories` (type: `array`):

Browse Substack's own categories (sorted by popularity).

## `maxNewsletters` (type: `integer`):

How many newsletters to return (each one is analyzed and charged).

## `onlyWithSponsors` (type: `boolean`):

Return only newsletters with at least one sponsored post among the scanned posts. Scans more candidates to fill your list; you're only charged for newsletters returned.

## `minSubscribers` (type: `integer`):

Skip small newsletters. Newsletters that hide their count are kept.

## `postsPerNewsletter` (type: `integer`):

How many recent posts to check for sponsors in each newsletter. More posts = better sponsor coverage.

## `language` (type: `string`):

Optional two-letter code, e.g. en, es, pt.

## `maxConcurrency` (type: `integer`):

Newsletters analyzed in parallel.

## Actor input object example

```json
{
  "keywords": [
    "fintech"
  ],
  "maxNewsletters": 30,
  "onlyWithSponsors": true,
  "minSubscribers": 1000,
  "postsPerNewsletter": 10,
  "maxConcurrency": 4
}
```

# Actor output Schema

## `newsletters` (type: `string`):

One row per newsletter: audience, cadence, engagement and past sponsors.

## `summary` (type: `string`):

Brands sponsoring newsletters in your niche, ranked by how many newsletters they sponsor.

# 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 = {
    "keywords": [
        "fintech"
    ]
};

// Run the Actor and wait for it to finish
const run = await client.actor("matidepa22/newsletter-sponsor-finder").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 = { "keywords": ["fintech"] }

# Run the Actor and wait for it to finish
run = client.actor("matidepa22/newsletter-sponsor-finder").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 '{
  "keywords": [
    "fintech"
  ]
}' |
apify call matidepa22/newsletter-sponsor-finder --silent --output-dataset

```

## MCP server setup

```json
{
    "mcpServers": {
        "apify": {
            "type": "http",
            "url": "https://mcp.apify.com/?tools=fetch-actor-details,matidepa22/newsletter-sponsor-finder"
        }
    }
}
```

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/DMVy6nqBLN0BS5GwL/builds/7Xlg3Kja3CCBsbWNk/openapi.json