PostOnce

PostOnce is a cross‑posting platform that lets creators and businesses publish content to multiple social media channels from a single dashboard. Users can connect accounts on TikTok, Instagram, YouTube, Facebook, LinkedIn, X, Threads, Bluesky, Pinterest and more, then schedule or instantly push posts across all selected networks. The service offers integrations with tools like ChatGPT, Canva, and n8n, and provides API access for automating workflows, managing media, and tracking performance.

PostOnce publishes 6 API contracts indexed on the APIs.io network, including Accounts API, Drafts API, Media API, and 3 more. Tagged areas include Company, Social Media, Automation, and Marketing.

The PostOnce catalog on APIs.io includes 1 JSON-LD context and 1 Spectral governance ruleset.

PostOnce’s developer surface includes changelog, authentication, documentation, API reference, getting-started guide, support, engineering blog, and 26 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

52.3/100 developing ▼ -8.7 Agent 53/100 agent native Heartbeat 100/100 alive Full breakdown ↓
scored 2026-11-06 · rubric v0.27.0 · Show this score on your site →

AccessPaid

1 published contract

Company Social Media Automation Marketing

What this lets a business do 1

Business capabilities this provider's published APIs can perform, derived from its own contracts. Browse all capabilities →

Media, Creator & Social

AE-170

Posts

POST /v1/posts POST /v1/posts/{id}/publish POST /v1/posts/{id}/targets/{targetId}/retry

Kin Score

Kin Score How this is scored →
scored 2026-11-06 · rubric v0.27.0

Composite quality — 52.3/100 · developing

Contract Quality 12.7 / 19

Developer Ergonomics 4.5 / 15

Access Clarity 9.3 / 15

Operational Transparency 3.9 / 10

Contract Governance 2.0 / 9

Discoverability 4.8 / 8

Regulatory Posture 3.1 / 15

Create-or-Update Ergonomics 2.8 / 10

Agent readiness — 53/100 · agent native

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 6 / 6

MCP Server 0 / 12

Machine-Readable Auth 10 / 10

Idempotency 9 / 9

Stable Error Semantics 8 / 8

Request/Response Examples 7 / 7

Rate-Limit Signaling 7 / 7

Typed Event Surface 0 / 6

Agent Skills 0 / 5

Well-Known Catalog 0 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 0 / 4

Delegated User Identity 6 / 6

Protected Resource Metadata 5 / 5

Registration Without a Human 6 / 6

Agentic Commerce Well-Known Document 0 / 5

Pagination 5 / 5

Distinct Operations 3 / 3

MCP Tool Quality 6 / 6

Regulatory Posture applies to this provider. Its tags matched the Horizontal (data, software, accessibility, platform) regime, so Regulatory Posture carries 15 points of the composite. If this regime is wrong for your business, say so on your provider repo — the applicability map is public and we will correct it.

Create-or-Update Ergonomics applies to this provider. This API accepts writes, so it carries 10 points of the composite. It is scored from the published contracts themselves: whether a caller can create-or-update in one call, whether the write accepts a key the caller already holds, and whether the response says which branch ran. Without that, every write needs a search-and-branch in front of it, and the first time that check is skipped a duplicate record is created. Scored against the observed mean rather than raw — a provider at the catalog average is unchanged by this facet, not penalised by it.

The six quality facets above are damped to 75 points between them, because the conditional facet above carries the other 25. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 75% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.

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Agent readiness — checks not met, largest first (exact, from this profile):

MCP Server +12 pts — deployment.mode + probe verdict on the mcp/ manifest, not the pointer; an unprobed slug falls back to authorship
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0
Typed Event Surface +6 pts — AsyncAPI document, OR webhooks/callbacks objects in the as-published OpenAPI, OR common[].type includes Webhooks
Agent Skills +5 pts — skills artifact present, graded by who authored it
Agentic Commerce Well-Known Document +5 pts — a parsing /.well-known/ucp.json or acp.json declaring a version and at least one service, OR (0.27) a live x402 payment challenge from _data/x402-adoption.json — `self` when its endpoints are on the provider's own domain, `platform` when they are on a vendor's
Dry-Run / Simulate Mode +4 pts — OpenAPI: destructive operations expose a dry_run / simulate / preview / validate_only parameter

2 more unmet checks in the Agent Readiness table above.

Kin Score — facets with the most composite points still available (weight × headroom):

Developer Ergonomics scores 29.8 — up to +14.0 composite points
Contract Governance scores 22.0 — up to +9.4 composite points
Contract Quality scores 67.7 — up to +8.1 composite points

Each check links to what satisfies it. Publish the artifact, or tell us where it already lives, and the score moves on the next scoring run.

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. Every facet and dimension name above is a link: it opens that measurement's own page — what it means, the exact checks that feed it, how the whole catalog distributes on it, and the providers at the top of it. This rating is computed from the provider profile at artifacts.apis.io/postonce/apis.yml: open an issue on github.com/api-evangelist/postonce to ask a question or point us at an artifact you publish. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

Standards implemented 3

Standards this provider implements or carries. De facto ones are profiled and measured by the API Commons; formal ones come from the standards directory and are linked by the provider's own tags. The evidence column says how each claim was established — not that it was made.

OAuth 2.0 Protected Resource Metadata

measured — observed by APIs.io (verified)

Dynamic Client Registration

measured — observed by APIs.io (published)

OpenAPI

measured — observed by APIs.io (published)

APIs 6

Individual APIs this provider publishes, each with its own machine-readable definition.

PostOnce Public API

Public API for PostOnce paid users

PostOnce Accounts API

The Accounts API from PostOnce — 3 operation(s) for accounts.

PostOnce Drafts API

The Drafts API from PostOnce — 2 operation(s) for drafts.

PostOnce Media API

The Media API from PostOnce — 2 operation(s) for media.

PostOnce Posts API

The Posts API from PostOnce — 5 operation(s) for posts.

PostOnce Workflows API

The Workflows API from PostOnce — 2 operation(s) for workflows.

PostOnce API pricing

Prices published by PostOnce, read 2026-10-14 from postonce.to/pricing.

Plan	Price
Creator	$29
Creator	$290
Pro	$69
Pro	$690
Agency	$199
Agency	$1,990

Plan details, limits and sources →

Rate limits

Starter and Creator request limit: 60 requests per minute per API key
Pro, Agency and Partner request limit: 300 requests per minute per API key

Rate-limit details →

Billed by: seat · FinOps profile →

Pricing Plans 2

Published pricing tiers and plan structures.

Postonce Plans Pricing

6 plans

PLANS

Postonce Price Estimates

0 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Postonce Rate Limits

2 limits

RATE LIMITS

Service Levels 1

Uptime the provider promises or reports, as SLA4OAI. Read from its own pages; APIs.io runs no monitors.

PostOnce

SLA

FinOps 1

Cost, billing, and metering signals for API financial operations.

Postonce Finops

FINOPS

Semantic Vocabularies 1

JSON-LD contexts and semantic vocabularies used across these APIs.

Postonce Context

14 classes · 53 properties

JSON-LD

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

PostOnce API Rules

54 rules · 49 errors 4 warnings 1 info

SPECTRAL

JSON Schema 6

Standalone JSON Schema definitions for this provider's data models.

Account

9 properties

JSON SCHEMA

ConnectAccountResponse

1 properties

JSON SCHEMA

MediaInput

7 properties

JSON SCHEMA

PostTargetInput

3 properties

JSON SCHEMA

Workflow

13 properties

JSON SCHEMA

WorkflowSettings

3 properties

JSON SCHEMA

Security Posture 2

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Postonce Authentication

1 scheme

SECURITY

Postonce Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Agentic Access 1

Recommended x-agentic-access execution contracts for AI agents.

Postonce Agentic Access

22 operations · 14 acting

AGENTIC

Resources

Get Started 2

Portal, sign-up, and the first successful call

Login

GettingStarted

GettingStarted

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

APIReference

APIReference

Agent Surfaces 3

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

AgenticAccess

LLMsTxt

LLMsTxt

WellKnown

WellKnown

Design & Contract 8

Pagination, idempotency, versioning, errors, and events

Spectral

JSONLD

Vocabulary

Conformance

DataModel

Idempotency

Conventions

ErrorCatalog

Scroll for all 8

Build 2

SDKs, sample code, and the tooling you integrate with

IntegrationEdges

IntegrationEdges

GitHubOrganization

GitHubOrganization

Access & Security 2

Authentication, authorization, and security posture

Authentication

Authentication

DomainSecurity

DomainSecurity

Operate 3

Status, limits, changes, and where to get help

RateLimits

RateLimits

ChangeLog

ChangeLog

Support

Support

Commercial 5

Pricing, plans, and the legal terms of use

FinOps

TermsOfService

PrivacyPolicy

Plans

Pricing

Company 2

The organization behind the API

Website

Website

Blog

Blog

Other 4

Properties that don't map to a standard resource type

CapabilityMap

AgentCard

Hosts

Vendors

Source (apis.yml)

aid: postonce
name: PostOnce
accessModel:
  pricing: paid
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Paid
  confidence: high
  probe_state: gated
  source:
  - plans
  - authentication
  - rate-limits
  - security
  generated: '2026-11-06'
  method: derived
image: https://postonce.to/og-image-v3.png?v=1
description: PostOnce is a cross‑posting platform that lets creators and businesses publish content to multiple social media
  channels from a single dashboard. Users can connect accounts on TikTok, Instagram, YouTube, Facebook, LinkedIn, X, Threads,
  Bluesky, Pinterest and more, then schedule or instantly push posts across all selected networks. The service offers integrations
  with tools like ChatGPT, Canva, and n8n, and provides API access for automating workflows, managing media, and tracking
  performance.
url: https://raw.githubusercontent.com/api-evangelist/postonce/refs/heads/main/apis.yml
x-type: company
x-source: harvest:new-submission
x-tier: profiled
x-tier-reason: enrichment pass 2026-10-14 (modular-v1; was harvest)
specificationVersion: '0.20'
created: '2026-10-14'
modified: '2026-10-14'
x-docs-platform: mintlify
x-docs-platform-confidence: medium
x-docs-platform-checked: 2026-10-17
x-docs-hosting: vercel
tags:
- Company
- Social Media
- Automation
- Marketing
tags_raw:
- Company
- Social Media
- Automation
- Marketing
- API
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: AgenticAccess
  url: agentic-access/postonce-agentic-access.yml
- type: FinOps
  url: finops/postonce-finops.yml
- type: IntegrationEdges
  url: integrations/postonce-integration-edges.yml
- type: CapabilityMap
  url: capabilities/postonce-capability-edges.yml
  name: PostOnce Business Capability Map
- type: Spectral
  url: rules/postonce-rules.yml
- type: JSONLD
  url: json-ld/postonce-context.jsonld
- type: Vocabulary
  url: vocabulary/postonce-vocabulary.yml
- type: Conformance
  url: conformance/postonce-conformance.yml
- type: TermsOfService
  url: https://postonce.to/tos
- type: PrivacyPolicy
  url: https://postonce.to/privacy-policy
- type: RateLimits
  url: rate-limits/postonce-rate-limits.yml
- type: Plans
  url: plans/postonce-plans-pricing.yml
- type: DataModel
  url: data-model/postonce-data-model.yml
- type: ChangeLog
  url: changelog/postonce-changelog.yml
- type: Idempotency
  url: conventions/postonce-conventions.yml
- type: Conventions
  url: conventions/postonce-conventions.yml
- type: Authentication
  url: authentication/postonce-authentication.yml
- type: ErrorCatalog
  url: errors/postonce-problem-types.yml
- type: LLMsTxt
  url: llms/postonce-llms.txt
- type: AgentCard
  url: a2a/postonce-a2a.yml
- type: WellKnown
  url: well-known/postonce-well-known.yml
- type: Hosts
  url: hosts/postonce-hosts.yml
- type: Vendors
  url: vendors/postonce-vendors.yml
- type: Login
  url: https://postonce.to/signin
- type: GitHubOrganization
  url: https://github.com/postoncehq
- type: DomainSecurity
  url: security/postonce-domain-security.yml
- type: Website
  url: https://postonce.to
- type: Documentation
  url: https://docs.postonce.to/introduction
- type: APIReference
  url: https://docs.postonce.to/api-reference/list-accounts
- type: GettingStarted
  url: https://docs.postonce.to/getting-started/authentication
- type: Support
  url: https://postonce.to/contact
- type: Blog
  url: https://postonce.to/blog
- type: Pricing
  url: https://postonce.to/pricing
apis:
- name: PostOnce Public API
  description: Public API for PostOnce paid users
  humanURL: https://docs.postonce.to/api-reference/list-accounts
  baseURL: https://postonce.to/api/public
  aid: postonce:postonce-public-api
- aid: postonce:postonce-accounts-api
  name: PostOnce Accounts API
  description: The Accounts API from PostOnce — 3 operation(s) for accounts.
  humanURL: https://docs.postonce.to/api-reference/list-accounts
  baseURL: https://postonce.to/api/public
  tags:
  - Account
  tags_raw:
  - Accounts
  properties:
  - type: OpenAPI
    url: openapi/postonce-accounts-api-openapi.yml
  - type: JSONSchema
    url: json-schema/postonce-workflow-settings-schema.json
  - type: JSONSchema
    url: json-schema/postonce-post-target-input-schema.json
  - type: JSONSchema
    url: json-schema/postonce-account-schema.json
  - type: JSONSchema
    url: json-schema/postonce-connect-account-response-schema.json
  - type: JSONSchema
    url: json-schema/postonce-media-input-schema.json
  - type: JSONSchema
    url: json-schema/postonce-workflow-schema.json
- aid: postonce:postonce-drafts-api
  name: PostOnce Drafts API
  description: The Drafts API from PostOnce — 2 operation(s) for drafts.
  humanURL: https://docs.postonce.to/api-reference/list-accounts
  baseURL: https://postonce.to/api/public
  tags:
  - Drafts
  properties:
  - type: OpenAPI
    url: openapi/postonce-drafts-api-openapi.yml
  - type: JSONSchema
    url: json-schema/postonce-workflow-settings-schema.json
  - type: JSONSchema
    url: json-schema/postonce-post-target-input-schema.json
  - type: JSONSchema
    url: json-schema/postonce-account-schema.json
  - type: JSONSchema
    url: json-schema/postonce-connect-account-response-schema.json
  - type: JSONSchema
    url: json-schema/postonce-media-input-schema.json
  - type: JSONSchema
    url: json-schema/postonce-workflow-schema.json
- aid: postonce:postonce-media-api
  name: PostOnce Media API
  description: The Media API from PostOnce — 2 operation(s) for media.
  humanURL: https://docs.postonce.to/api-reference/list-accounts
  baseURL: https://postonce.to/api/public
  tags:
  - Media
  properties:
  - type: OpenAPI
    url: openapi/postonce-media-api-openapi.yml
  - type: JSONSchema
    url: json-schema/postonce-workflow-settings-schema.json
  - type: JSONSchema
    url: json-schema/postonce-post-target-input-schema.json
  - type: JSONSchema
    url: json-schema/postonce-account-schema.json
  - type: JSONSchema
    url: json-schema/postonce-connect-account-response-schema.json
  - type: JSONSchema
    url: json-schema/postonce-media-input-schema.json
  - type: JSONSchema
    url: json-schema/postonce-workflow-schema.json
- aid: postonce:postonce-posts-api
  name: PostOnce Posts API
  description: The Posts API from PostOnce — 5 operation(s) for posts.
  humanURL: https://docs.postonce.to/api-reference/list-accounts
  baseURL: https://postonce.to/api/public
  tags:
  - Posts
  properties:
  - type: OpenAPI
    url: openapi/postonce-posts-api-openapi.yml
  - type: JSONSchema
    url: json-schema/postonce-workflow-settings-schema.json
  - type: JSONSchema
    url: json-schema/postonce-post-target-input-schema.json
  - type: JSONSchema
    url: json-schema/postonce-account-schema.json
  - type: JSONSchema
    url: json-schema/postonce-connect-account-response-schema.json
  - type: JSONSchema
    url: json-schema/postonce-media-input-schema.json
  - type: JSONSchema
    url: json-schema/postonce-workflow-schema.json
- aid: postonce:postonce-workflows-api
  name: PostOnce Workflows API
  description: The Workflows API from PostOnce — 2 operation(s) for workflows.
  humanURL: https://docs.postonce.to/api-reference/list-accounts
  baseURL: https://postonce.to/api/public
  tags:
  - Workflows
  properties:
  - type: OpenAPI
    url: openapi/postonce-workflows-api-openapi.yml
  - type: JSONSchema
    url: json-schema/postonce-workflow-settings-schema.json
  - type: JSONSchema
    url: json-schema/postonce-post-target-input-schema.json
  - type: JSONSchema
    url: json-schema/postonce-account-schema.json
  - type: JSONSchema
    url: json-schema/postonce-connect-account-response-schema.json
  - type: JSONSchema
    url: json-schema/postonce-media-input-schema.json
  - type: JSONSchema
    url: json-schema/postonce-workflow-schema.json
x-submission-notes: 'Real cross-posting API, but submitted by grokbot.com third-party listing agent, not the provider | Kin
  approved listing 2026-10-14 (case-by-case: Real cross-posting API, but submitted by grokbot.com third-party listing agent,
  not the provider)'
x-submission-probe: root 200, docs 200; soft-404 ok
x-submitted-by: postonce@mail.grokbot.com (apis.io/add, 2026-10-14)
x-coverage:
  state: gated
  reason: partner-login
  method: derived
  generated: '2026-10-14'
  generator: derive-coverage.py (pre-flight evidence)
  detail: the company serves an API surface but requires credentials before any description of it can be read
  evidence:
  - url: https://docs.postonce.to/mcp
    status: null
  - url: https://postonce.to/openapi.json
    status: null
  - url: https://postonce.to/mcp
    status: 401
  - url: https://postonce.to
    status: 200
x-enrichment:
  date: '2026-10-14'
  status: enriched
  artifacts_added: 37
  pass: modular-v1
  engine: identity=local,contract=local,surfaces=local,docs=local,regulatory=local

PostOnce API — frequently asked questions

Does PostOnce have an API?

Yes. APIs.io lists 6 APIs from PostOnce, including PostOnce Public API, PostOnce Accounts API and PostOnce Drafts API, and 3 more.

Is there an OpenAPI specification for the PostOnce API?

Yes. APIs.io indexes 5 OpenAPI specifications for PostOnce, each linked for download from this page.

How do I authenticate with the PostOnce API?

PostOnce documents its authentication (1 scheme). The details are profiled on APIs.io as Postonce Authentication.

How much does the PostOnce API cost?

PostOnce publishes its prices; its Creator plan is $29 as of 2026-10-14. APIs.io lists 6 pricing plans for PostOnce, with each plan's price, limits and inclusions under Pricing on this page.

Is the PostOnce API ready for AI agents?

PostOnce has a Kin Score of 52.3 out of 100 (developing) and an Agent Readiness score of 53.3 (agent-native), scored by API Evangelist on 2026-11-06.

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