Just Captions

Just Captions provides a simple tool to add AI-generated captions to any video. Users can upload videos, choose from multiple caption styles, and export subtitles in various formats. The service supports over 50 languages, offers word-level timestamps, and includes features like emoji and word highlights. It offers a free tier with 30 audio minutes per month and a paid plan for higher usage, targeting creators, marketers, and developers integrating captioning into their workflows.

Just Captions publishes 14 API contracts indexed on the APIs.io network, including Billing API, Correct API, Emoji API, and 11 more. Tagged areas include Video, Artificial Intelligence, Captioning, Productivity, and Software-as-a-Service.

The Just Captions catalog on APIs.io includes 1 Spectral governance ruleset.

Just Captions’ developer surface includes support, changelog, getting-started guide, authentication, documentation, API reference, engineering blog, and 14 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

35.6/100 thin Agent 27/100 agent aware Full breakdown ↓
scored 2026-11-13 · rubric v0.28.0 · Show this score on your site →

1 published contract 1 Agent Skills

Video Artificial Intelligence Captioning Productivity Software-as-a-Service Company

Kin Score

Kin Score How this is scored →
scored 2026-11-13 · rubric v0.28.0

Composite quality — 35.6/100 · thin

Contract Quality 9.7 / 21

Developer Ergonomics 8.4 / 17

Access Clarity 2.9 / 17

Operational Transparency 1.6 / 11

Contract Governance 1.9 / 10

Discoverability 5.6 / 9

Regulatory Posture 2.6 / 15

Agent readiness — 27/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 0 / 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 0 / 7

Typed Event Surface 0 / 6

Agent Skills 5 / 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 0 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 0 / 5

Pagination 5 / 5

Distinct Operations 0 / 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 could not be measured. We hold no machine-readable contract for this provider to read, so there is nothing to measure a write surface against. Excluded rather than scored zero: never-measured and measured-empty are different facts. Publishing an OpenAPI is what makes this facet — and several others — scorable at all.

The six quality facets above are damped to 85 points between them, because the conditional facet above carries the other 15. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 85% 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 Ask about this →
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0 Ask about this →
Rate-Limit Signaling +7 pts — OpenAPI responses document X-RateLimit-* / RateLimit headers (verified), else a rate_limits artifact or RateLimits link (documented) Ask about this →
Registration Without a Human +6 pts — a `registration_endpoint` in the served RFC 8414 / OIDC discovery document Ask about this →
Delegated User Identity +6 pts — a served discovery document listing authorization_code in grant_types_supported (served), else an oauth2 authorizationCode flow or openIdConnect declared in an OpenAPI (documented) Ask about this →
Typed Event Surface +6 pts — AsyncAPI document, OR webhooks/callbacks objects in the as-published OpenAPI, OR common[].type includes Webhooks Ask about this →

7 more unmet checks in the Agent Readiness table above.

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

Access Clarity scores 17.0 — up to +16.6 composite points Ask about this →
Contract Quality scores 45.5 — up to +13.6 composite points Ask about this →
Operational Transparency scores 14.3 — up to +11.1 composite points Ask about this →

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.

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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/justcaptions-com/apis.yml: open an issue on github.com/api-evangelist/justcaptions-com 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 1

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.

OpenAPI

measured — observed by APIs.io (published)

APIs 14

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

Just Captions Billing API

The Billing API from Just Captions — 4 operation(s) for billing.

Just Captions Correct API

The Correct API from Just Captions — 1 operation(s) for correct.

Just Captions Emoji API

The Emoji API from Just Captions — 1 operation(s) for emoji.

Just Captions Estimate API

The Estimate API from Just Captions — 1 operation(s) for estimate.

Just Captions Fonts API

The Fonts API from Just Captions — 1 operation(s) for fonts.

Just Captions Health API

The Health API from Just Captions — 1 operation(s) for health.

Just Captions Keys API

The Keys API from Just Captions — 3 operation(s) for keys.

Just Captions Limits API

The Limits API from Just Captions — 1 operation(s) for limits.

Just Captions Pricing API

The Pricing API from Just Captions — 1 operation(s) for pricing.

Just Captions Signup API

The Signup API from Just Captions — 1 operation(s) for signup.

Just Captions Styles API

The Styles API from Just Captions — 1 operation(s) for styles.

Just Captions Transcribe API

The Transcribe API from Just Captions — 1 operation(s) for transcribe.

Just Captions Translate API

The Translate API from Just Captions — 1 operation(s) for translate.

Just Captions Usage API

The Usage API from Just Captions — 1 operation(s) for usage.

Scroll for all 14

Agent Skills 1

Packaged agent skills for driving this provider's APIs from an AI assistant.

justcaptions-com-caption-workflow

AGENT SKILL

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs. Counts are the severity each rule declares, not results of running them.

Just Captions API Rules

41 rules · 36 error-severity 4 warn-severity 1 info-severity

SPECTRAL

Security Posture 2

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

Just Captions Authentication

http · 1 scheme

SECURITY

Just Captions Domain Security

TLSv1.3

SECURITY

Agentic Access (API Evangelist recommendations) 1

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

Just Captions Agentic Access

20 operations · 12 acting · 2 human-in-the-loop

20 operations · 12 acting

AGENTIC

Resources

Get Started 1

Portal, sign-up, and the first successful call

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

AgentSkill

AgentSkill

LLMsTxt

LLMsTxt

Design & Contract 5

Pagination, idempotency, versioning, errors, and events

Spectral

Idempotency

Conventions

ErrorCatalog

Conformance

Access & Security 2

Authentication, authorization, and security posture

Authentication

Authentication

DomainSecurity

DomainSecurity

Operate 2

Status, limits, changes, and where to get help

Support

Support

ChangeLog

ChangeLog

Commercial 2

Pricing, plans, and the legal terms of use

TermsOfService

TermsOfService

PrivacyPolicy

PrivacyPolicy

Company 2

The organization behind the API

Website

Website

Blog

Blog

Other 2

Properties that don't map to a standard resource type

Hosts

Hosts

Vendors

Vendors

Source (apis.yml)

aid: justcaptions-com
name: Just Captions
accessModel:
  pricing: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source:
  - authentication
  - security
  generated: '2026-11-13'
  method: derived
image: https://justcaptions.com/assets/og.png
description: Just Captions provides a simple tool to add AI-generated captions to any video. Users can upload videos, choose
  from multiple caption styles, and export subtitles in various formats. The service supports over 50 languages, offers word-level
  timestamps, and includes features like emoji and word highlights. It offers a free tier with 30 audio minutes per month
  and a paid plan for higher usage, targeting creators, marketers, and developers integrating captioning into their workflows.
url: https://artifacts.apis.io/justcaptions-com/apis.yml
x-type: company
x-source: harvest:mcp-registry
x-tier: profiled
x-tier-reason: enrichment pass 2026-11-13 (modular-v1; was harvest)
specificationVersion: '0.20'
created: '2026-11-13'
modified: '2026-11-13'
tags:
- Video
- Artificial Intelligence
- Captioning
- Productivity
- Software-as-a-Service
- Company
tags_raw:
- Video
- AI
- Captioning
- Productivity
- SaaS
- Company
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: AgenticAccess
  url: agentic-access/justcaptions-com-agentic-access.yml
- type: Spectral
  url: rules/justcaptions-com-rules.yml
- type: AgentSkill
  url: skills/_index.yml
- type: Idempotency
  url: conventions/justcaptions-com-conventions.yml
- type: Conventions
  url: conventions/justcaptions-com-conventions.yml
- type: ErrorCatalog
  url: errors/justcaptions-com-problem-types.yml
- type: Conformance
  url: conformance/justcaptions-com-conformance.yml
- type: LLMsTxt
  url: llms/justcaptions-com-llms.txt
- type: Hosts
  url: hosts/justcaptions-com-hosts.yml
- type: Vendors
  url: vendors/justcaptions-com-vendors.yml
- type: Support
  url: https://justcaptions.com/api/support/
- type: ChangeLog
  url: https://github.com/SpaceSheepBoy/justcaptions-support-packs/releases/download/mac-direct-1.0-5/JustCaptions-Mac-1.0-5-universal.dmg
- type: GettingStarted
  url: https://justcaptions.com/agents/
- type: Authentication
  url: authentication/justcaptions-com-authentication.yml
- type: DomainSecurity
  url: security/justcaptions-com-domain-security.yml
- type: Website
  url: https://justcaptions.com/
- type: Documentation
  url: https://justcaptions.com/api/
- type: APIReference
  url: https://justcaptions.com/api/docs/
- type: Blog
  url: https://justcaptions.com/blog/
- type: TermsOfService
  url: https://justcaptions.com/api/terms/
- type: PrivacyPolicy
  url: https://spacesheepboy.github.io/JustCaptions-legal/privacy/
apis:
- aid: justcaptions-com:justcaptions-com-billing-api
  name: Just Captions Billing API
  description: The Billing API from Just Captions — 4 operation(s) for billing.
  humanURL: https://justcaptions.com/api/docs/
  baseURL: https://api.justcaptions.com/v1
  tags:
  - Billing
  properties:
  - type: OpenAPI
    url: openapi/justcaptions-com-billing-api-openapi.yml
- aid: justcaptions-com:justcaptions-com-correct-api
  name: Just Captions Correct API
  description: The Correct API from Just Captions — 1 operation(s) for correct.
  humanURL: https://justcaptions.com/api/docs/
  baseURL: https://api.justcaptions.com/v1
  tags:
  - Correct
  properties:
  - type: OpenAPI
    url: openapi/justcaptions-com-correct-api-openapi.yml
- aid: justcaptions-com:justcaptions-com-emoji-api
  name: Just Captions Emoji API
  description: The Emoji API from Just Captions — 1 operation(s) for emoji.
  humanURL: https://justcaptions.com/api/docs/
  baseURL: https://api.justcaptions.com/v1
  tags:
  - Emoji
  properties:
  - type: OpenAPI
    url: openapi/justcaptions-com-emoji-api-openapi.yml
- aid: justcaptions-com:justcaptions-com-estimate-api
  name: Just Captions Estimate API
  description: The Estimate API from Just Captions — 1 operation(s) for estimate.
  humanURL: https://justcaptions.com/api/docs/
  baseURL: https://api.justcaptions.com/v1
  tags:
  - Estimate
  properties:
  - type: OpenAPI
    url: openapi/justcaptions-com-estimate-api-openapi.yml
- aid: justcaptions-com:justcaptions-com-fonts-api
  name: Just Captions Fonts API
  description: The Fonts API from Just Captions — 1 operation(s) for fonts.
  humanURL: https://justcaptions.com/api/docs/
  baseURL: https://api.justcaptions.com/v1
  tags:
  - Fonts
  properties:
  - type: OpenAPI
    url: openapi/justcaptions-com-fonts-api-openapi.yml
- aid: justcaptions-com:justcaptions-com-health-api
  name: Just Captions Health API
  description: The Health API from Just Captions — 1 operation(s) for health.
  humanURL: https://justcaptions.com/api/docs/
  baseURL: https://api.justcaptions.com/v1
  tags:
  - Health
  properties:
  - type: OpenAPI
    url: openapi/justcaptions-com-health-api-openapi.yml
- aid: justcaptions-com:justcaptions-com-keys-api
  name: Just Captions Keys API
  description: The Keys API from Just Captions — 3 operation(s) for keys.
  humanURL: https://justcaptions.com/api/docs/
  baseURL: https://api.justcaptions.com/v1
  tags:
  - Keys
  properties:
  - type: OpenAPI
    url: openapi/justcaptions-com-keys-api-openapi.yml
- aid: justcaptions-com:justcaptions-com-limits-api
  name: Just Captions Limits API
  description: The Limits API from Just Captions — 1 operation(s) for limits.
  humanURL: https://justcaptions.com/api/docs/
  baseURL: https://api.justcaptions.com/v1
  tags:
  - Limits
  properties:
  - type: OpenAPI
    url: openapi/justcaptions-com-limits-api-openapi.yml
- aid: justcaptions-com:justcaptions-com-pricing-api
  name: Just Captions Pricing API
  description: The Pricing API from Just Captions — 1 operation(s) for pricing.
  humanURL: https://justcaptions.com/api/docs/
  baseURL: https://api.justcaptions.com/v1
  tags:
  - Pricing
  properties:
  - type: OpenAPI
    url: openapi/justcaptions-com-pricing-api-openapi.yml
- aid: justcaptions-com:justcaptions-com-signup-api
  name: Just Captions Signup API
  description: The Signup API from Just Captions — 1 operation(s) for signup.
  humanURL: https://justcaptions.com/api/docs/
  baseURL: https://api.justcaptions.com/v1
  tags:
  - Sign Up
  tags_raw:
  - Signup
  properties:
  - type: OpenAPI
    url: openapi/justcaptions-com-signup-api-openapi.yml
- aid: justcaptions-com:justcaptions-com-styles-api
  name: Just Captions Styles API
  description: The Styles API from Just Captions — 1 operation(s) for styles.
  humanURL: https://justcaptions.com/api/docs/
  baseURL: https://api.justcaptions.com/v1
  tags:
  - Styles
  properties:
  - type: OpenAPI
    url: openapi/justcaptions-com-styles-api-openapi.yml
- aid: justcaptions-com:justcaptions-com-transcribe-api
  name: Just Captions Transcribe API
  description: The Transcribe API from Just Captions — 1 operation(s) for transcribe.
  humanURL: https://justcaptions.com/api/docs/
  baseURL: https://api.justcaptions.com/v1
  tags:
  - Transcribe
  properties:
  - type: OpenAPI
    url: openapi/justcaptions-com-transcribe-api-openapi.yml
- aid: justcaptions-com:justcaptions-com-translate-api
  name: Just Captions Translate API
  description: The Translate API from Just Captions — 1 operation(s) for translate.
  humanURL: https://justcaptions.com/api/docs/
  baseURL: https://api.justcaptions.com/v1
  tags:
  - Translate
  properties:
  - type: OpenAPI
    url: openapi/justcaptions-com-translate-api-openapi.yml
- aid: justcaptions-com:justcaptions-com-usage-api
  name: Just Captions Usage API
  description: The Usage API from Just Captions — 1 operation(s) for usage.
  humanURL: https://justcaptions.com/api/docs/
  baseURL: https://api.justcaptions.com/v1
  tags:
  - Usage
  properties:
  - type: OpenAPI
    url: openapi/justcaptions-com-usage-api-openapi.yml
x-enrichment:
  date: '2026-11-13'
  status: enriched
  artifacts_added: 20
  pass: modular-v1
  engine: identity=local,contract=local,surfaces=local,docs=local,regulatory=local

Just Captions API — frequently asked questions

Does Just Captions have an API?

Yes. APIs.io lists 14 APIs from Just Captions, including Just Captions Billing API, Just Captions Correct API and Just Captions Emoji API, and 11 more.

Is there an OpenAPI specification for the Just Captions API?

Yes. APIs.io indexes 14 OpenAPI specifications for Just Captions, each linked for download from this page.

How do I authenticate with the Just Captions API?

Just Captions uses bearer-token authentication (http · 1 scheme). The details are profiled on APIs.io as Just Captions Authentication.

Is the Just Captions API ready for AI agents?

Just Captions has a Kin Score of 35.6 out of 100 (thin) and an Agent Readiness score of 27.3 (agent-aware), scored by API Evangelist on 2026-11-13.

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