# Substack API: Search newsletters

> Finds public Substack newsletters matching a topic, in Substack's search order. Subscriber counts are null when Substack does not display one.

Unofficial. Not affiliated with or endorsed by Substack.

- Page: https://fous.com/methods/substack.com/search-newsletters
- Method: `substack.com/search_newsletters`, version 1
- Website: substack.com
- Returns: name, author, description, subscriber count, paid subscription flag, logo, newsletter link
- Effect: read (it gets data and changes nothing)
- Sign-in: none needed
- Cost: 1 credit per completed run (1¢ with pay as you go); failed runs are free
- Verified: Nov 2, 2026

## Inputs

| Field | Type | Required | In the run below | Description |
|---|---|---|---|---|
| `topic` | string | yes | `"personal finance"` | Words describing newsletters to find, for example, product management. |
| `max_results` | integer | no | `50` | Maximum newsletters to return, for example, 20. Default 20. |

## Output

From a run on Oct 23, 2026, shortened. Its input:

```json
{
  "topic": "personal finance",
  "max_results": 50
}
```

Its output:

```json
{
  "newsletters": [
    {
      "name": "Beyond Your Budget",
      "author": "Michela Allocca",
      "description": "Helping you reach your 6-figure savings goals!",
      "logo_image_link": "https://substackcdn.com/image/fetch/$s_!r3xM!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F32003b2c-1b1f-4ba0-bc06-767055ffd484_630x630.png",
      "newsletter_link": "https://breakyourbudget.substack.com",
      "subscriber_count": "Over 10,000 subscribers",
      "offers_paid_subscriptions": true
    },
    {
      "name": "The Crunch",
      "author": "The Money Cruncher, CPA",
      "description": "The Crunch provides weekly tips to ordinary people on how to build wealth. \n\nMy weekly newsletter arrives in your inbox every Saturday and tells you everything you need to know about personal finance in just 5 minutes.",
      "logo_image_link": "https://substackcdn.com/image/fetch/$s_!vbpr!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F7e4f1095-bf04-44be-aa64-2189474d599e_1280x1280.png",
      "newsletter_link": "https://thecrunchcpa.substack.com",
      "subscriber_count": "Over 4,000 subscribers",
      "offers_paid_subscriptions": true
    },
    {
      "name": "The Finance Notebook📝",
      "author": "The Finance Notebook📝",
      "description": "By Yukti Manglani | A finance student documenting what I learn- one concept, one insight, one day at a time.",
      "logo_image_link": "https://substackcdn.com/image/fetch/$s_!sv9p!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F09aaa04a-108c-43ed-ae84-4fc48d468594_1170x1170.png",
      "newsletter_link": "https://yuktimanglani.substack.com",
      "subscriber_count": "Over 15,000 subscribers",
      "offers_paid_subscriptions": false
    }
  ]
}
```

## Run it

From code, with a Fous API key in `FOUS_API_KEY`; the answer's `data` holds the output:

```bash
curl https://api.fous.com/v1/runs \
  -H "Authorization: Bearer $FOUS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"method":"substack.com/search_newsletters","input":{"topic":"personal finance","max_results":50}}'
```

From an AI agent connected to the Fous MCP server: its `run` with the same method and input. To connect one, give it `set up https://fous.com/SKILL.md`.

## Ask your agent

- Find me public newsletters about product management on Substack, up to 10 results.
- Which climate change newsletters have the most subscribers? Show me the top 20 from Substack.
- I need paid newsletters on personal finance and investing, with their authors and descriptions.
- Look up indie game development newsletters and include their logos and links, max 15.
- Search for Substack newsletters covering remote work tips, showing whether each one is paid.

## Input schema

```json
{
  "type": "object",
  "required": [
    "topic"
  ],
  "properties": {
    "topic": {
      "type": "string",
      "minLength": 1,
      "description": "Words describing newsletters to find, for example, product management."
    },
    "max_results": {
      "type": "integer",
      "default": 20,
      "maximum": 50,
      "minimum": 1,
      "description": "Maximum newsletters to return, for example, 20."
    }
  }
}
```

## Output schema

```json
{
  "type": "object",
  "required": [
    "newsletters"
  ],
  "properties": {
    "newsletters": {
      "type": "array",
      "items": {
        "type": "object",
        "required": [
          "name",
          "author",
          "description",
          "subscriber_count",
          "offers_paid_subscriptions",
          "logo_image_link",
          "newsletter_link"
        ],
        "properties": {
          "name": {
            "type": "string"
          },
          "author": {
            "type": [
              "string",
              "null"
            ]
          },
          "description": {
            "type": [
              "string",
              "null"
            ]
          },
          "logo_image_link": {
            "type": [
              "string",
              "null"
            ]
          },
          "newsletter_link": {
            "type": "string"
          },
          "subscriber_count": {
            "type": [
              "string",
              "null"
            ],
            "description": "Subscriber count as shown on Substack, or null when not displayed."
          },
          "offers_paid_subscriptions": {
            "type": "boolean"
          }
        },
        "additionalProperties": false
      },
      "description": "Matching newsletters in Substack search order."
    }
  },
  "additionalProperties": false
}
```

## See more

- [Substack API: List newsletter posts](https://fous.com/methods/substack.com/list-newsletter-posts.md): Finds a Substack newsletter by name or web address and returns its latest public posts with dates, authors, access level and engagement counts.
- [Medium API: List topic articles](https://fous.com/methods/medium.com/list-topic-articles.md): Lists public Medium articles for a topic, newest first or popular this week, with author, publication, reading time, claps and membership status.
- [ESPN API: List news for a league or team](https://fous.com/methods/espn.com/list-news.md): Finds an ESPN league or team by name and lists the latest headlines ESPN publishes for it, newest first.
- [Google API: List top stories](https://fous.com/methods/news.google.com/list-top-stories.md): Lists the current top Google News stories, overall or for one topic, in a chosen country and language edition.
- [Meetup API: Search events](https://fous.com/methods/meetup.com/search-events.md): Finds upcoming public Meetup events by topic and city, sorted by start time. Only events that mention the topic are included; external costs and undisclosed venues may not be shown.
- [Polymarket API: Search markets](https://fous.com/methods/polymarket.com/search-markets.md): Finds Polymarket prediction markets about a topic, ranked by total trading volume, with outcome chances and market details.
- [Product Hunt API: Search products](https://fous.com/methods/producthunt.com/search-products.md): Finds Product Hunt products by name or by what they do, in Product Hunt search order, with tagline, review rating, review count, followers and topics. Ratings are null for products without reviews.
- [Britannica API: Get article](https://fous.com/methods/britannica.com/get-article.md): Finds the best-matching Britannica encyclopedia article for a topic and returns its introduction, quick facts, section headings, update date and main image.
- [All Substack methods](https://fous.com/methods/substack.com.md)