Reddit Subreddit Finder — Community Discovery

Find Reddit communities related to your topic and export a ranked list with original links, descriptions and available weekly activity estimates. Use it for audience research, community discovery, content planning and identifying discussions to review.

Quick start

1. Enter topics such as hiking and camping.
2. Choose a maximum result count and match threshold.
3. Set a spending limit. Start with a $3 maximum charge for two topics.
4. Run the Actor, open Overview, then check the coverage summary in OUTPUT.

{
  "topics": ["hiking", "camping"],
  "maxResults": 25,
  "minRelevance": 50,
  "maxRunSeconds": 240,
  "region": "US"
}

The result count is a maximum, not a guaranteed number. The Actor reads the available community search cards, up to 30 per topic; it does not promise an exhaustive directory.

Matching and ranking

• 100: the community name contains the full topic after spaces and punctuation are removed.
• 50: the description contains the topic phrase.
• 0: no supported name or description match; these communities are excluded.

For example, machine learning can match r/machinelearning. Matching is a text-based signal, not a semantic or AI relevance score. Synonyms are not inferred. Use English or Latin-alphabet topics with at least two letters/numbers; non-Latin-only or punctuation-only topics have no supported match.

Set minRelevance to 100 for name matches only, or 50 to include description matches. The default 0 also excludes unrelated communities. Rows rank by relevance, then weekly visitors. Communities found under several topics appear once, with those sources in discoveredIn.

Inputs

Input	Default	Meaning
topics	Required	Up to 20 unique search topics
maxResults	50	Maximum saved communities, from 1 to 200
minRelevance	0	Match threshold, from 0 to 100
region	US	Access location: US, DE, GB, FR, CA or AU
maxRunSeconds	240	Collection budget after initialization, from 30 to 900 seconds

region does not filter communities or authors by country. Startup and cleanup add to total run time. Time and spending limits can stop collection before all topics are searched.

Output

Field	Meaning
name, url	Subreddit name and original community link
description	Available description from the search result
weeklyVisitors	Displayed weekly visitor estimate
weeklyContributions	Displayed weekly contribution estimate
relevanceScore	Best supported topic match: 50 or 100
nicheConfidence	high for name match, medium for description match
discoveredIn	Topics whose search results contained the community
observedAt	Observation timestamp

Weekly metrics describe the displayed activity period. Values abbreviated as K/M are rounded estimates; missing values remain null. These are not subscriber or member counts.

Dataset views:

• Overview: ranked matches, activity, descriptions and links.
• Community activity: weekly visitor/contribution estimates.
• Topics & descriptions: match sources, descriptions and observation time.

The OUTPUT record contains searched sources, unavailable/stopped/no-match topics, filters, emitted counts and billing counters. PARTIAL means a time or spending limit stopped work; saved rows remain usable. The platform run may still show success because those rows were finalized correctly.

Unconfirmed empty pages, recognized errors and access blocks are reported as unavailable. A confirmed no-results page, or loaded results with no relevant communities, can correctly produce zero rows. Review coverage before treating a scan as complete.

Pricing

Event	Price
Run start	$0.05 per GB of memory, minimum one GB
Community search-page attempt	$0.25
Unique community saved to this run dataset	$0.02

At the default 2 GB, the start fee is $0.10. Every attempted topic search is charged before navigation, including retries, blocked pages and attempts that produce no matching communities. Browser resource files are not separate events.

A community saved once in a run is charged once. Saving it again in a later run is charged again. Examples without retries, using default memory:

• Two search pages and 25 saved communities: $1.10.
• Two search pages and 10 saved communities: $0.80.
• One search page and zero saved communities: $0.35.

These are billing examples, not guarantees of coverage or result count. The minimum maximum charge is $0.40; a small cap can stop output after only a few rows. A $3 cap gives more room for the two-topic example and retries. The Actor checks spending before search navigation and dataset writes.

API and integrations

Use immutable Actor ID BJcMldaDqWuL2p8a6 so integrations remain stable if the Store name changes:

POST https://api.apify.com/v2/actors/BJcMldaDqWuL2p8a6/runs?maxTotalChargeUsd=3
Authorization: Bearer YOUR_APIFY_TOKEN
Content-Type: application/json

Send the quick-start JSON as the request body, then poll the returned run ID:

GET https://api.apify.com/v2/actor-runs/RUN_ID
Authorization: Bearer YOUR_APIFY_TOKEN

Read rows and coverage from the returned default storage IDs:

GET https://api.apify.com/v2/datasets/DATASET_ID/items?clean=true&format=json
GET https://api.apify.com/v2/key-value-stores/KEY_VALUE_STORE_ID/records/OUTPUT
Authorization: Bearer YOUR_APIFY_TOKEN

Schedule repeated discovery in Apify or connect exports to your database and automation tools.

This independent research tool is not affiliated with Reddit.