The substack API from AnyAPI — 1 operation(s) for substack.
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openapi: 3.2.0
info:
contact:
email: support@getanyapi.com
description: 'Any API, one wallet, USD, no subscriptions. Each API is a single discovered operation: send the normalized input, get a normalized result. Prices and payment outcomes are reported in USD; each operation documents the settlement policy for its enabled payment rails.'
title: Any Substack API
version: 1.0.0
x-guidance: 'Use each operation''s published method and path with its normalized JSON input (see the operation requestBody). Before setting a client or tool timeout, GET /v1/apis/{sku} and inspect its trailing-30-day latency p50/p95/p99 and sample; p99 is an observation, not a maximum. To pay: send your AnyAPI key (Authorization: Bearer, billed from your USD wallet). For operations that advertise an inline rail, pay per call inline with x402 - call with no key, receive HTTP 402 with a PAYMENT-REQUIRED header, then retry with the PAYMENT-SIGNATURE header (base, no account needed); or pay per call inline with MPP (Machine Payments Protocol) - call with no key, receive HTTP 402 with a WWW-Authenticate: Payment challenge, then retry with the Authorization: Payment header (tempo, no account needed). x402 settles after execution; execution failure is reported as released; mpp settles before execution; execution failure is reported as charged_undelivered.'
servers:
- url: https://api.getanyapi.com
security:
- bearerAuth: []
- apiKeyAuth: []
tags:
- name: substack
x-group: Substack
paths:
/v1/run/substack.posts:
post:
description: 'Pull posts from any Substack publication by its URL, or pass a single post URL (…/p/slug) to fetch just that one article. Returns title, subtitle, publish date, paywall status, word count, engagement (reactions, comments, restacks), author profile, and full article HTML.
**Price:** billed per result - \$5.50 per 1,000 requests base + \$1.72 per 1,000 results, capped at \$178.00 per 1,000 requests.
**Routing:** one lane serves this API today, so a failed attempt has nowhere to fail over to. Payment outcome follows the selected rail''s settlement policy.
**Catalog:** Substack Posts pricing and uptime - live USD price, lane routing, and measured 30-day uptime. Every Substack endpoint.'
operationId: substack_posts
parameters:
- description: Optional. Comma-separated keys (dotted paths like `author.name` descend into nested objects) to keep on each result item. Keys are matched relative to each result item after the `data`/`items` envelope is unwrapped, not against the top-level response envelope, so use `jq` to reshape the whole envelope. Shrinks the response without changing cost.
in: query
name: fields
required: false
schema:
type: string
- description: Optional. Cap the number of result rows returned; a `_truncated` note reports how many were withheld so you can page via the API's own `limit`. Does not change cost.
in: query
name: max_items
required: false
schema:
minimum: 0
type: integer
- description: Optional. Return only a structural outline (top-level keys, item counts, and per-field byte sizes) instead of the full data. Does not change cost.
in: query
name: summary
required: false
schema:
type: boolean
- description: 'Optional. A jq expression applied to the result envelope; its output replaces `output` (multiple outputs collect into an array). Reshape freely, e.g. `jq=.data | {title, description, md: .markdown[:3500]}`. Runs sandboxed with a 250ms / 2MB budget; on failure the full result is returned with a `jqError`. Does not change cost.'
in: query
name: jq
required: false
schema:
type: string
- description: Optional. The most you are willing to pay for this one request, in US dollars (for example 0.05). Any route that would charge more than this is not used, so a request only ever runs on something you can afford. If nothing is available at or below your amount, the request is refused before it runs, nothing is charged, and the message tells you the cheapest price per request so you can raise it. Leave it out to accept the normal price.
in: query
name: max_cost_usd
required: false
schema:
type: string
- description: Optional wallet idempotency key, scoped to this customer for 24 hours. When the gateway honors the key, this synchronous in-process execution can continue after the caller disconnects, bounded by its execution deadline. A completed replayable result charges normally exactly once and can be replayed without another provider run or charge. A pending duplicate returns 409 idempotency_in_progress; reuse with different request semantics returns 409 idempotency_conflict.
in: header
name: Idempotency-Key
required: false
schema:
maxLength: 255
minLength: 1
type: string
requestBody:
content:
application/json:
example:
limit: 3
url: https://www.astralcodexten.com
schema:
additionalProperties: false
example:
limit: 3
url: https://www.astralcodexten.com
properties:
contentType:
default: all
description: Restrict to a single post type, or 'all' (e.g. newsletter).
enum:
- all
- newsletter
- podcast
- thread
type: string
endDate:
description: Only return posts published on or before this date, format YYYY-MM-DD (e.g. 2024-12-31). Applied within the most recent 'limit' posts scanned.
type: string
includeContent:
default: true
description: Include the full article body as HTML. Set false for metadata only (e.g. false).
type: boolean
limit:
description: Maximum number of recent posts to return when given a publication URL (1-100, default 25); ignored for a single post URL, which always returns that one post. You are billed per post returned, so a lower limit costs less.
maximum: 100
minimum: 1
type: integer
onlyFree:
default: false
description: Return only free (non-paywalled) posts (e.g. true).
type: boolean
preferLatencyUnderMs:
description: 'Optional; omit it and routing is unchanged, with the cheapest source serving. Prefer sources whose typical response time (median over the trailing 30 days, as published on this endpoint''s lane health) is under this many milliseconds; among those, the cheapest serves. This can raise your price: when the cheapest source misses the target, a faster and dearer one serves, and you are quoted and charged its price. If no source is that fast the request is still served, by whichever source offers the best speed for its price - it is never refused for being slow. Sources we have not timed are tried last. This is a preference, not a guarantee: the median describes past requests and is not a ceiling on this one, and it excludes any wait this request itself asks for. On a paginated walk it applies to the first page only: later pages stay with the source that page chose, at the price it was quoted.'
minimum: 1
type: integer
startDate:
description: Only return posts published on or after this date, format YYYY-MM-DD (e.g. 2024-01-01). Applied within the most recent 'limit' posts scanned, so raise 'limit' to reach older date ranges.
type: string
url:
description: Either a Substack publication URL / custom domain to fetch its recent posts (e.g. https://www.astralcodexten.com), OR a single post URL to fetch just that one article with full content (e.g. https://www.astralcodexten.com/p/your-book-review).
type: string
required:
- url
title: Substack posts input
type: object
required: true
responses:
'200':
content:
application/json:
schema:
properties:
costUsd:
description: USD charged on the original run. On a replay this value is echoed for parity; the replay itself is free.
type: number
hint:
description: 'Optional one-line nudge, absent when there is nothing to say. `large_result:` suggests the fields/max_items/summary/jq controls for a big response. `paging_unavailable:` means this result came from a source that cannot return a `nextCursor`, so it may be INCOMPLETE and cannot be continued - re-run with `requireCursor: true` to be served only by a source that can page, which may cost more per request.'
type: string
items:
description: Number of result rows returned. For per-result SKUs the per-item cost is charged against this count; for input-priced SKUs the charge is per submitted input, independent of this count.
type: integer
jqError:
description: Present only when a `jq` expression failed; `output` then carries the full unshaped result and this explains why the reshape did not apply.
type: string
output:
anyOf:
- additionalProperties: false
properties:
data:
description: Result payload, or null when nothing was found.
oneOf:
- type: 'null'
- additionalProperties: false
properties:
items:
description: 'Post records: title, subtitle, URL, publish date, paywall status, word count, engagement (reactions, comments, restacks), author profile, publication info, and full article HTML when requested. Populated whenever the provider has data for the entity.'
items:
properties:
authorHandle:
description: Handle of the post author. Populated whenever the provider has data for the entity.
type: string
x-anyapi-must-populate: true
authorName:
description: Display name of the post author. Populated whenever the provider has data for the entity.
type: string
x-anyapi-must-populate: true
commentCount:
description: Number of comments on the post.
type: integer
createdUtc:
description: UTC epoch timestamp in seconds (Unix time). Multiply by 1000 for a JS Date in milliseconds. Populated whenever the provider has data for the entity.
type: number
x-anyapi-must-populate: true
description:
description: Post description or article HTML/summary. Populated whenever the provider has data for the entity.
type: string
x-anyapi-must-populate: true
image:
description: Cover image URL. Populated whenever the provider has data for the entity.
type: string
x-anyapi-must-populate: true
isPaid:
description: Whether the post is behind a paywall.
type: boolean
postId:
description: Substack post identifier. Populated whenever the provider has data for the entity.
type: string
x-anyapi-must-populate: true
postType:
description: Post type (e.g. newsletter, podcast, thread). Populated whenever the provider has data for the entity.
type: string
x-anyapi-must-populate: true
reactionCount:
description: Number of reactions on the post.
type: integer
subtitle:
description: Post subtitle or deck. Populated whenever the provider has data for the entity.
type: string
x-anyapi-must-populate: true
title:
description: Post title. Populated whenever the provider has data for the entity.
type: string
x-anyapi-must-populate: true
url:
description: Canonical post URL. Populated whenever the provider has data for the entity.
type: string
x-anyapi-must-populate: true
wordcount:
description: Approximate word count of the article.
type: integer
required:
- title
- url
type: object
type: array
x-anyapi-must-populate: true
required:
- items
type: object
found:
description: Whether any posts were found for the request.
type: boolean
required:
- found
- data
title: Substack posts output
type: object
- type: 'null'
description: Normalized output, or null when the replay payload was not retained.
provider:
description: Always "AnyAPI".
type: string
replayed:
description: True when this response replays the durable result of an earlier run without billing or upstream execution.
type: boolean
resultId:
description: Opaque handle to the full unshaped result, cached ~15 min. Re-shape it for free (fields/max_items/summary/jq) via GET /v1/results/{id}, no re-billing. Absent when the result was too large to cache.
type: string
required:
- output
- provider
- costUsd
- items
- replayed
type: object
description: Normalized result.
headers:
Idempotency-Replayed:
description: Present only when the request carried an Idempotency-Key this gateway honored. "false" means the key was claimed and the run executed freshly; "true" means it replayed a prior identical run and was NOT charged again. Absent means either no key was sent or this gateway does not honor keys, so a retry could be charged twice.
schema:
enum:
- 'false'
- 'true'
type: string
PAYMENT-RESPONSE:
description: Inline x402 payment receipt.
schema:
type: string
Payment-Receipt:
description: Inline mpp payment receipt.
schema:
type: string
X-PAYMENT-RESPONSE:
description: Inline x402 payment receipt.
schema:
type: string
'400':
content:
application/json:
schema:
$ref: '#/components/schemas/Error'
description: Input did not match the schema, or the upstream rejected the request.
'401':
content:
application/json:
schema:
$ref: '#/components/schemas/Error'
description: Missing or invalid API key.
'402':
content:
application/json:
schema:
oneOf:
- $ref: '#/components/schemas/PaymentRequiredError'
- $ref: '#/components/schemas/TrialCapReached'
application/problem+json:
schema:
properties:
challengeId:
minLength: 1
type: string
status:
const: 402
type: integer
required:
- status
- challengeId
type: object
description: Insufficient wallet balance or spend cap, or an inline-payment challenge. Agent trials receive a trial_cap_reached continuation with a live RFC 8628 device authorization.
headers:
PAYMENT-REQUIRED:
description: Inline x402 payment challenge.
schema:
type: string
WWW-Authenticate:
description: Inline mpp payment challenge.
schema:
type: string
'404':
content:
application/json:
schema:
$ref: '#/components/schemas/Error'
description: Unknown SKU, or the upstream had no matching resource.
'409':
content:
application/json:
schema:
$ref: '#/components/schemas/Error'
description: 'Idempotency collision. Codes: idempotency_in_progress means retry after the Retry-After delay; idempotency_conflict means use a new key for different request semantics; idempotency_needs_review means stop retrying and contact AnyAPI support with X-Anyapi-Request-Id.'
'422':
content:
application/json:
schema:
$ref: '#/components/schemas/Error'
description: The request was well formed but this API cannot serve the requested target site; the body's `alternatives` array lists the AnyAPI APIs that can.
'429':
content:
application/json:
schema:
$ref: '#/components/schemas/Error'
description: The upstream was rate limited; inspect `payment` when present before deciding whether to retry.
'500':
content:
application/json:
schema:
$ref: '#/components/schemas/Error'
description: An internal error prevented completion. Inspect payment when present before retrying.
'502':
content:
application/json:
schema:
$ref: '#/components/schemas/Error'
description: Every provider failed with a server/transport error, or inline payment settlement could not be confirmed; inspect `payment` when present before retrying.
security:
- bearerAuth: []
- apiKeyAuth: []
- {}
summary: Substack Posts
tags:
- substack
x-mint:
href: /api-reference/substack/posts
x-payment-info:
price:
currency: USD
max: '0.178000'
min: '0.005500'
mode: dynamic
protocols:
- x402:
asset: '0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913'
network: eip155:8453
payTo: '0x754BD2A6799e766B1E2b9f1Ae7fBdC0CeD96ef13'
scheme: exact
- mpp:
asset: '0x20c000000000000000000000b9537d11c60e8b50'
currency: USD
intent: charge
method: tempo
network: tempo
payTo: '0x754BD2A6799e766B1E2b9f1Ae7fBdC0CeD96ef13'
rail: tempo
scheme: exact
rails:
- headers:
challenge:
- PAYMENT-REQUIRED
credential:
- PAYMENT-SIGNATURE
- X-PAYMENT
receipt:
- PAYMENT-RESPONSE
- X-PAYMENT-RESPONSE
pricing:
currency: USD
max: '0.178000'
min: '0.005500'
minimumUsd: '0.001000'
mode: dynamic
quoteBasis: floor
protocol:
asset: '0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913'
network: eip155:8453
payTo: '0x754BD2A6799e766B1E2b9f1Ae7fBdC0CeD96ef13'
scheme: exact
rail: x402
settlement:
onExecutionFailure: released
onUnknownFinalization: indeterminate
timing: after_execution
- headers:
challenge:
- WWW-Authenticate
credential:
- Authorization
receipt:
- Payment-Receipt
pricing:
currency: USD
max: '0.178000'
min: '0.005500'
minimumUsd: null
mode: dynamic
quoteBasis: funded_ceiling
protocol:
asset: '0x20c000000000000000000000b9537d11c60e8b50'
currency: USD
intent: charge
method: tempo
network: tempo
payTo: '0x754BD2A6799e766B1E2b9f1Ae7fBdC0CeD96ef13'
rail: tempo
scheme: exact
rail: mpp
settlement:
onExecutionFailure: charged_undelivered
onVerificationError: indeterminate
timing: before_execution
components:
schemas:
AgentUpgrade:
properties:
authorizationServer:
format: uri
type: string
clientId:
type: string
device:
$ref: '#/components/schemas/DeviceUpgrade'
scope:
type: string
required:
- authorizationServer
- scope
type: object
Payment:
properties:
costUsd:
description: Known USD payment amount for this request.
minimum: 0
type: number
rail:
minLength: 1
type: string
settlementState:
enum:
- charged_undelivered
- indeterminate
type: string
required:
- rail
- settlementState
- costUsd
type: object
Error:
properties:
code:
description: Stable machine-readable error code when the endpoint defines one.
type: string
error:
description: Customer-safe error message.
type: string
payment:
$ref: '#/components/schemas/Payment'
requestId:
description: This run's AnyAPI request id, the same value as the X-Anyapi-Request-Id response header. Quote it to support. Absent on endpoints that do not execute a run.
format: uuid
type: string
required:
- error
type: object
PaymentRequiredError:
allOf:
- $ref: '#/components/schemas/Error'
- properties:
error:
not:
const: trial_cap_reached
type: object
DeviceUpgrade:
properties:
deviceCode:
type: string
expiresIn:
minimum: 0
type: integer
grantType:
type: string
interval:
minimum: 1
type: integer
tokenEndpoint:
format: uri
type: string
userCode:
type: string
verificationUri:
format: uri
type: string
verificationUriComplete:
format: uri
type: string
required:
- verificationUriComplete
- verificationUri
- userCode
- deviceCode
- tokenEndpoint
- grantType
- interval
- expiresIn
type: object
TrialCapReached:
properties:
error:
const: trial_cap_reached
type: string
message:
description: Human-relayable continuation instructions, including an executable token poll.
type: string
upgrade:
$ref: '#/components/schemas/AgentUpgrade'
required:
- error
- message
- upgrade
type: object
securitySchemes:
apiKeyAuth:
description: Your AnyAPI key.
in: header
name: X-API-Key
type: apiKey
x-default: YOUR_ANYAPI_KEY
bearerAuth:
description: Your AnyAPI key as a Bearer token.
scheme: bearer
type: http
x-default: YOUR_ANYAPI_KEY