Data points

Markdown

A data point is one extra fact about a source, a person or a post. Subscriber counts, chart positions, how often a publication posts, engagement on an issue.

They sit apart from the main fields because they are observations rather than properties. A value can change over time, and it is not always there.

{
  "key": "inbound_corpus_links",
  "value": 11649,
  "source": "derived:corpus",
  "fetched_at": "2026-08-19T04:11:02Z"
}

Field	What it holds
`key`	What this fact is.
`value`	The value. A number, a string, or a small object, depending on the key.
`source`	Where we got it. See below.
`fetched_at`	When we last observed it.

Where a value came from

Every data point says where it came from. Use it to judge a number: a subscriber count a platform publishes is a different kind of fact from one we worked out ourselves.

We share this detail with customers rather than publishing it. Sign in to read it.

Where they appear

Data points come back on the detail response for a source, a person or a post. They are not on list rows, because loading them costs a query per item.

/api/v1/sources/<slug>
/api/v1/people/<slug>
/api/v1/posts/<slug>

What to expect

They are sparse. A key exists for a publication only if we could observe it. Most sources have some data points and no source has all of them. Always check whether the key is there before reading it.

Keys are not a fixed schema. We add keys as we learn to observe new things, and stop refreshing ones that stop being available. Read the keys you recognise and ignore the rest. You may see a source not listed above, from a collector we have retired.

Values are point-in-time. fetched_at tells you how fresh a number is. A subscriber count from three months ago is still a useful order of magnitude and is not today's number.

Some counts are bucketed. Where a platform reports a range rather than an exact figure, the value is the bottom of the bucket. A paid_subscriber_bucket of 1000 means at least a thousand, not exactly a thousand.

Audience and reach, on a source

The ones most people want. These tell you how big a publication is and how active it is.

Key	What it holds
`subscriber_count_free`	Free subscribers, where the platform publishes it.
`paid_subscriber_bucket`	Paid subscribers, as the bottom of a bucket.
`leaderboard_rank`	Its rank in its category, where it appears in one.
`leaderboard_category`	The category that rank is in.
`apple_chart_ranks`	Podcast chart positions, by country and category.
`episode_count`	Episodes published, for a podcast.
`total_post_count`	Posts we hold for it.

Activity and standing, on a source

Key	What it holds
`posting_cadence_per_week`	Posts per week, averaged.
`posting_consistency`	How regular that cadence is, from 0 to 1. A weekly show that never misses scores high.
`feed_age_days`	How long it has been publishing.
`inbound_corpus_links`	How many times other publications we index have linked to it. A rough measure of standing among its peers.
`has_custom_domain`	Whether it publishes on its own domain.
`feed_hosts`	Who writes or hosts it, with each person's share of its posts and their person slug.

Identity, on a source

Key	What it holds
`author_name`, `owner_name`	Names the feed declares.
`owner_email`	The contact address in the feed. Publishers put this there deliberately.
`feed_language`	The language the feed declares.
`genres`	Podcast genres.
`explicit`	Whether the feed marks itself explicit.
`artwork_url`, `itunes_id`	Cover art and the Apple id, for a podcast.
`twitter_handle`	Where the publication declares one.

On a person

Key	What it holds
`follower_count`	Followers on the platform they publish through.
`subscriber_count_bucket`	Subscribers to their own publication, as the bottom of a bucket.
`bestseller_tier`	A platform badge for paid-subscriber milestones. The number is the tier, not a count.
`author_publications`	Publications they write for.
`author_socials`	Links they list on their profile.
`publication_email`, `email`	Contact addresses declared in a feed.

On a post

Engagement, where the publishing platform reports it.

Key	What it holds
`reaction_count`	Likes on the issue.
`comment_count`, `child_comment_count`	Comments, and replies to comments.
`restack_count`	Times it was reshared on the platform.
`word_count`	Length.
`paywall_status`	Whether the issue was paywalled.
`post_type`	What kind of item it is.
`is_audio`	Whether it carries audio.
`section_name`	The publication's own section, where it uses them.

Using them

Ranking coverage by audience size is the common one. Search for mentions, fetch each publication, and sort by subscriber_count_free or apple_chart_ranks.

Fetching one source per result costs a call each, so scope the search first and fetch only the publications you are going to report on. See API intro.