GET/social-media/{socialMediaId}/follower-history

Returns daily follower/subscriber snapshots for one connected account, plus the current count and the net change over the range. Build growth charts without storing your own snapshots. The latest count is also on GET /social-media/my-social-accounts.

https://api.postfa.st/Auth: pf-api-keyRate limit: 200 requests per hour

How the range works

from and to are optional ISO 8601 dates. Omit both for the last 90 days; the window is capped at 365 days, so an older from is clamped to one year before to.

series is ordered oldest-first and limited to the requested range. currentFollowerCount and trackingStartedAt always reflect the account's full history, so the current count can be newer than the last point in series when to is in the past.

Snapshots are captured once per UTC day (around 04:00 UTC), the same source as followerCount on /social-media/my-social-accounts. A temporary platform outage can skip a day, leaving a gap in series.

Counts are bigint strings

currentFollowerCount, delta, and each series[].followerCount are numeric strings (bigint-safe), e.g. "1234" not 1234. Parse them with BigInt or a bigint-safe parser rather than parseInt for very large accounts.

An account id that is not in your workspace (or has no history yet) returns 200 with an empty series and the count fields omitted, never an error. A non-UUID id returns 400.

Path parameters

socialMediaIdstring (UUID)required

The connected account id, from /social-media/my-social-accounts. Must be a valid UUID, otherwise the request returns 400.

Query parameters

fromISO 8601optional

Start of the range, e.g. 2026-03-01T00:00:00.000Z. Defaults to 90 days before to. The window is capped at 365 days, so a from older than that is clamped to one year before to.

toISO 8601optional

End of the range, e.g. 2026-06-01T00:00:00.000Z. Defaults to now.

Follower history by platform

PlatformTrackedNotes
InstagramYesBusiness/Creator accounts
FacebookYesPages only; personal accounts are not tracked
YouTubeYesSubscribers (approximate; hidden-subscriber channels return no count)
ThreadsYes
PinterestYes
BlueskyYes
TelegramYesChannel/group members; the PostFast bot must remain in the chat
LinkedInYesOrganization Pages only; personal profiles are not tracked
X (Twitter)Not tracked
TikTokNot tracked
Google Business ProfileNot tracked

History accrues from the day tracking begins; there is no backfill for the period before an account was connected.

Response

200 OK Follower history for the account. series and delta cover the requested range; currentFollowerCount and trackingStartedAt reflect the account's full history.

socialMediaIdstring (UUID)required

The account id you requested, echoed back.

currentFollowerCountstring (bigint)optional

Latest captured follower/subscriber count overall (not limited to the range), as a numeric string. Omitted until the first daily capture.

deltastringoptional

Net change across the range: currentFollowerCount minus the first captured count within the range. A signed numeric string - decreases are prefixed with - (e.g. -123); increases have no leading sign (e.g. 57). Omitted when the range contains no captured count.

trackingStartedAtISO 8601optional

Date of the earliest snapshot on record for this account (when PostFast began tracking it). Omitted if no count has ever been captured.

seriesarrayoptional

Daily snapshots within the range, oldest first.

capturedAtISO 8601optional

The UTC day the count was captured for.

followerCountstring (bigint)optional

Follower/subscriber count on that day, as a numeric string. Omitted for a day with no captured value.