Substack Reactors API
The people who reacted to a post, up to the 100 Substack lists, with their public profile details.
GET /v1/substack/posts/{post}/reactors1 credit Failed requests are free
About this endpoint
GET /v1/substack/posts/{post}/reactors lists the people who reacted to a post. The post is a numeric id or a canonical post URL. data.postId names the post.
data.reactors[] carries id, name, photoUrl, bestsellerTier, badges and a primaryPublication summary with id, name and subdomain. Substack lists at most 100 people per post, so a 100-row response sets truncated to true. lookupStatus is found or not_found.
Substack Reactors API FAQ
What is in a reactor row?
The reader's numeric id, display name, photo and badges, plus the publication Substack marks as their primary one. The list does not include private account data.
How many reactors can I get?
Substack lists at most 100 people per post. A 100-row response sets truncated to true because it is at that limit.
Does this include restacks?
No. Reactions and restacks are separate lists. Use post.restackers.list for restacks.
How many credits does a reactors lookup cost?
Pricing is documented on the operation in the API registry (shown on this page). Confirm on every response with meta.creditsCharged: that field is the billing source of truth.
Other Substack endpoints
- PublicationGET /v1/substack/publications/{publication}
- PostsGET /v1/substack/publications/{publication}/posts
- Post bodiesGET /v1/substack/publications/{publication}/posts/bodies
- Post indexGET /v1/substack/publications/{publication}/posts/index
- Search postsGET /v1/substack/publications/{publication}/posts/search
- RecommendationsGET /v1/substack/publications/{publication}/recommendations
- Publication feedGET /v1/substack/publications/{publication}/feed
- PostGET /v1/substack/posts/{post}