Substack Publication posts API

POST

API health

24h health: Normal
24h average time: —
Last checked: September 26, 2026 at 18:04 (UTC)

Healthy / normal
Available
Limited
Mostly down

Health APINormal

Last 24 hours

Last 30 days

How health is measured

Health = the share of calls that returned data, in percent. Empty results, failures and unknown outcomes do not count as returning data.
Levels: 90% and above is healthy, 70% and above is available, 40% and above is limited; anything lower is mostly down.
A period (the last 24 hours, one hour or one day) gets a score only once it has at least 50 calls. Periods with fewer calls show as normal: a few failures among a handful of calls do not mean the API is down.
Calls include real customer calls and our own daily probe calls. Request errors (wrong parameters, no balance) are excluded.
Average time counts only calls that completed normally: response time for sync calls, acceptance to completion for async ones.

By period

Time (UTC)	Status	Health	Average time
2026-09-26 18:00 - 18:59	Normal	—	—
2026-09-26 17:00 - 17:59	Normal	—	—
2026-09-26 16:00 - 16:59	Normal	—	—
2026-09-26 15:00 - 15:59	Normal	—	—
2026-09-26 14:00 - 14:59	Normal	—	—
2026-09-26 13:00 - 13:59	Normal	—	—
2026-09-26 12:00 - 12:59	Normal	—	—
2026-09-26 11:00 - 11:59	Normal	—	—
2026-09-26 10:00 - 10:59	Normal	—	—
2026-09-26 09:00 - 09:59	Normal	—	—
2026-09-26 08:00 - 08:59	Normal	—	—
2026-09-26 07:00 - 07:59	Normal	—	—
2026-09-26 06:00 - 06:59	Normal	—	—
2026-09-26 05:00 - 05:59	Normal	—	—
2026-09-26 04:00 - 04:59	Normal	—	—
2026-09-26 03:00 - 03:59	Normal	—	—
2026-09-26 02:00 - 02:59	Normal	—	—
2026-09-26 01:00 - 01:59	Normal	—	—
2026-09-26 00:00 - 00:59	Normal	—	—
2026-09-25 23:00 - 23:59	Normal	—	—
2026-09-25 22:00 - 22:59	Normal	—	—
2026-09-25 21:00 - 21:59	Normal	—	—
2026-09-25 20:00 - 20:59	Normal	—	—
2026-09-25 19:00 - 19:59	Normal	—	—
2026-09-26	Normal	—	—
2026-09-25	Normal	—	—
2026-09-24	Normal	—	—
2026-09-23	Normal	—	—
2026-09-22	Normal	—	—
2026-09-21	Normal	—	—
2026-09-20	Normal	—	—
2026-09-19	Normal	—	—
2026-09-18	Normal	—	—
2026-09-17	Normal	—	—
2026-09-16	Normal	—	—
2026-09-15	Normal	—	—
2026-09-14	Normal	—	—
2026-09-13	Normal	—	—
2026-09-12	Normal	—	—
2026-09-11	Normal	—	—
2026-09-10	Normal	—	—
2026-09-09	Normal	—	—
2026-09-08	Normal	—	—
2026-09-07	Normal	—	—
2026-09-06	Normal	—	—
2026-09-05	Normal	—	—
2026-09-04	Normal	—	—
2026-09-03	Normal	—	—
2026-09-02	Normal	—	—
2026-09-01	Normal	—	—
2026-08-31	Normal	—	—
2026-08-30	Normal	—	—
2026-08-29	Normal	—	—
2026-08-28	Normal	—	—

Retrieve publication posts from Substack. Accepts these parameters: url, since, until, and content_type. Returns these fields: reading_time_minutes, subtitle, publication_handle, and posted_at.

Price $1.39 per 1,000 requests ($0.001389 per call). Failed calls and empty results are not charged. Synchronous. For slow jobs add "mode": "async" to the body, take the job_id and poll.

Request parameters

Name	In	Type	Required	Default	Description
`Authorization`	header	`string`	Yes	-	Bearer followed by your API key. Create it in the console; never put it in a URL or a code repository.
`platform`	body	`string`	Yes	`substack`	Platform identifier, fixed value.
`action`	body	`string`	Yes	`publication_posts`	Capability identifier, fixed value.
`url`	body.params	Not declared	Yes	-	Specifies the target Substack resource link. Use publication homepages for publication and publication_posts, or direct /p/ post links for post and comments. The publication action requires a URL containing a recognizable Substack handle (custom domains may not parse), whereas publication_posts accepts custom domain links directly.
`content_type`	body.params	`enum`	No	-	Filters publication posts by content format using all_types, newsletter_posts_only, podcast_episodes_only, or threads_only. Field presence must be verified against specific post links, and setting this value does not unlock paywalled content.Allowed values`all_typesnewsletter_posts_onlypodcast_episodes_onlythreads_only`
`since`	body.params	Not declared	No	-	Specifies the start date string for filtering posts or activity feeds within a date range. Its presence in shared profile or publication parameters does not enable account creation date filtering.
`until`	body.params	Not declared	No	-	Specifies the end date string for filtering posts or activity feeds alongside since. This parameter does not represent subscription expiration dates or trigger complete historical archive exports.
`limit`	body.params	`integer (1–30)`	No	`10`

Code samples

bash

curl -X POST 'https://api.everyinfra.com/api/v1/social' \
  -H "Authorization: Bearer $EVERYINFRA_API_KEY" \
  -H 'Content-Type: application/json' \
  --data-raw '{
  "platform": "substack",
  "action": "publication_posts",
  "params": {
    "url": "https://astralcodexten.substack.com"
  }
}'

[OpenAPI definition (JSON)]Samples read the key from the EVERYINFRA_API_KEY environment variable; copied code never contains your key.

Response example

Real response

Captured September 26, 2026 at 08:56 (UTC) by calling this API with the parameters in the code sample above. results and count are that call's real response with personal information (names, handles, avatars, profile links, contact details) removed; the list keeps the first 2. id, billing and quota differ on every call, so only their shape is shown.

json

{
  "id": "req_…",
  "platform": "substack",
  "action": "publication_posts",
  "results": [
    {
      "id": 210681369,
      "url": "https://www.astralcodexten.com/p/your-book-review-lee-kuan-yews-memoirs",
      "title": "Your Book Review: Lee Kuan Yew's Memoirs",
      "subtitle": "Finalist #10 in the Book Review Contest",
      "text": "Finalist #10 in the Book Review Contest",
      "author_name": "（已隐去）",
      "author_username": "（已隐去）",
      "publication_name": "Astral Codex Ten",
      "publication_url": "https://www.astralcodexten.com",
      "like_count": 139,
      "comment_count": 31,
      "repost_count": 2,
      "word_count": 5683,
      "post_type": "newsletter",
      "audience": "everyone",
      "is_paid": false,
      "image_url": "https://substack-post-media.s3.amazonaws.com/public/images/3d745943-c11a-4ff0-9c6a-aaf91333ac9f_2546x2560.jpeg",
      "posted_at": "2026-09-25T22:26:10.306000+00:00",
      "updated_at": "2026-09-25T22:30:06.391000+00:00",
      "platform": "substack"
    },
    {
      "id": 215593613,
      "url": "https://www.astralcodexten.com/p/fall-meetups-2026-call-for-meetup",
      "title": "Fall Meetups 2026 - Call For Meetup Organizers",
      "subtitle": "...",
      "text": "...",
      "author_name": "（已隐去）",
      "author_username": "（已隐去）",
      "publication_name": "Astral Codex Ten",
      "publication_url": "https://www.astralcodexten.com",
      "like_count": 46,
      "comment_count": 18,
      "repost_count": 0,
      "word_count": 2086,
      "post_type": "newsletter",
      "audience": "everyone",
      "is_paid": false,
      "image_url": "https://substack-post-media.s3.amazonaws.com/public/images/53c58a6c-168a-4394-8fd1-2c4335f9eb12_1000x667.jpeg",
      "posted_at": "2026-09-25T06:06:18.720000+00:00",
      "updated_at": "2026-09-25T06:11:54.223000+00:00",
      "platform": "substack"
    }
  ],
  "count": 10,
  "billing": { … },
  "quota": { … }
}

Response fields

Business data is in results. The table lists the fields a record can contain; values the source does not provide are never made up.

Field	Meaning
`id`	The record's unique ID on the source platform. Unique only within one platform; IDs can repeat across platforms.
`url`	Link to the record on the source platform.
`title`	Title. null when the platform has no titles (for example text-only posts).
`subtitle`	Keeps the platform's own meaning
`text`	Body text with HTML removed. Long text may be truncated.
`author_name`	Author's display name.
`author_username`	Author's username (@handle), usually usable in URLs.
`publication_name`	Keeps the platform's own meaning
`publication_handle`	Keeps the platform's own meaning
`publication_url`	Keeps the platform's own meaning
`like_count`	Likes. null means the platform or this capability does not disclose it; it is not 0.
`comment_count`	Comments. null means not disclosed, not 0.
`repost_count`	Reposts (as distinct from quote posts). null means not disclosed.
`word_count`	Keeps the platform's own meaning
`reading_time_minutes`	Keeps the platform's own meaning
`post_type`	Keeps the platform's own meaning
`audience`	Keeps the platform's own meaning
`is_paid`	Keeps the platform's own meaning
`podcast_url`	Keeps the platform's own meaning
`image_url`	Image link. Capabilities with several images may return an image_urls array.
`posted_at`	Publish time in ISO 8601, UTC (for example 2026-08-07T12:34:56+00:00). Non-standard strings from the platform are passed through as is, so parse defensively. null means the platform does not disclose it.
`updated_at`	Keeps the platform's own meaning
`tags`	Array of tags. An empty array, not null, when there are none.
`platform`	Source platform identifier, the same as platform in the request (for example xiaohongshu, tiktok).

Errors and billing

401: Missing or invalid key. Authentication runs before parameter checks, so unauthenticated requests never see the parameter schema.
422: Wrong parameter name or value. The error lists the parameters and allowed values this capability accepts and the closest match; it happens before any charge.
402: Insufficient balance. Top up first.
429: Per-minute request limit reached. Wait for Retry-After and try again.
503: Could not complete right now. Any charge for the call goes back to your balance automatically, and the billing receipt in the response states the actual outcome, including when it is not yet known. Do not resend blindly.
200 empty: The request completed without data and is not charged (billing.reason = empty_result_refunded).

Official references

Used only to check objects and terms. They do not imply authorization or endorsement of EveryInfra by the platform.

Substack: Article, Audio, and Video Formats vs. Content Permissions ↗
Substack categorizes text, audio, and video posts as distinct content formats and maintains a strict separation between public materials and private articles. The `content_type` parameter on this page uses its own allowed values, which do not add video types or guarantee that filtering and retrieval are verified across every execution path.
Checked 2026-09-04