Arpeggi Labs

Arpeggi Labs is the company behind Kits AI, a studio-quality AI music and audio platform for musicians, producers, and developers. Kits AI provides voice cloning and conversion, an AI singing generator with 100+ royalty-free artist voice models, vocal isolation, stem separation, AI mastering, and a voice-model blender, alongside an ethically sourced "Earn" program that pays vocalists to license digital clones of their voice. The Kits AI API exposes these capabilities as asynchronous inference jobs over a REST interface at arpeggi.io/api/kits/v1, authenticated with a bearer API key: create a voice conversion, vocal separation, stem split, or voice-blend job, then poll for the signed output file URLs. Arpeggi Labs is an a16z portfolio company; its earlier product was Arpeggi Studio, a web3 in-browser music creation platform.

Arpeggi Labs publishes 5 API contracts indexed on the APIs.io network, including Stem Splitter API, Vocal Separation API, Voice Blender API, and 2 more. Tagged areas include Company, Music, Audio, Artificial Intelligence, and Voice.

The Arpeggi Labs catalog on APIs.io includes 1 Spectral governance ruleset.

Arpeggi Labs’ developer surface includes authentication, documentation, API reference, getting-started guide, support, engineering blog, pricing, and 19 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

46.0/100 developing ▬ flat Agent 24/100 agent aware Front door AI 6/6 dominant Heartbeat 12/100 dormant saas Full breakdown ↓
scored 2026-11-06 · rubric v0.27.0 · Show this score on your site →

1 published contract 3 Agent Skills

Company Music Audio Artificial Intelligence Voice Machine Learning Generative AI Media

What this lets a business do 1

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

AI Model Services

AE-110

Stem SplitterVocal SeparationVoice Conversion

POST /voice-conversions POST /stem-splits POST /vocal-separations

Kin Score

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

Composite quality — 46.0/100 · developing

Contract Quality 9.5 / 19

Developer Ergonomics 8.8 / 15

Access Clarity 6.7 / 15

Operational Transparency 2.3 / 10

Contract Governance 1.6 / 9

Discoverability 5.5 / 8

Regulatory Posture 3.4 / 15

Create-or-Update Ergonomics 0.0 / 10

Agent readiness — 24/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 10 / 10

Idempotency 0 / 9

Stable Error Semantics 8 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 7 / 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 3 / 3

MCP Tool Quality 6 / 6

Regulatory Posture applies to this provider. Its tags matched the AI & Biometrics 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
Agentic Access Contract +10 pts — agentic_access artifact present (x-agentic-access), graded by author
Idempotency +9 pts — OpenAPI mutating operations declare an idempotency key — a header, a request-body property, or a named de-duplication token whose own description says so (verified); else common[].type matches /idempoten/i (documented)
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0
Request/Response Examples +7 pts — share of operations carrying request/response examples; else an Examples / Code Samples link
Registration Without a Human +6 pts — a `registration_endpoint` in the served RFC 8414 / OIDC discovery document

8 more unmet checks in the Agent Readiness table above.

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

Contract Quality scores 50.6 — up to +12.4 composite points
Access Clarity scores 44.7 — up to +11.1 composite points
Operational Transparency scores 23.7 — up to +9.9 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/arpeggi-labs/apis.yml: open an issue on github.com/api-evangelist/arpeggi-labs 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 →

Markets this provider is in provisional

The Kin Score Market layer reads a provider inside its market: its position, and how deep its integrations go. Depth is only comparable within a position. Provisional and unweighted: not part of the Kin Score or agent readiness.

Market	Position	Depth	Registered MCP server	Declares compatibility
Music and Rights	undeclared	-	-	-

Registered MCP server and declares compatibility are report only — not weighted. Undeclared means we found nothing we can read, so there is no number: we never infer integrations.

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 5

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

Arpeggi Labs Stem Splitter API

Split an audio track into vocal and instrument stems.

Arpeggi Labs Vocal Separation API

Isolate vocals from a mixed audio track.

Arpeggi Labs Voice Blender API

Blend two to four voice models into a new voice model.

Arpeggi Labs Voice Conversion API

Convert an input performance to a target voice model.

Arpeggi Labs Voice Models API

Browse and retrieve available voice models.

Open Collections 5

Open, tool-agnostic API collections (OpenAPI-derived and Bruno).

Kits AI Stem Splitter API

OPEN COLLECTION

Kits AI Stem Splitter Vocal Separation API

OPEN COLLECTION

Kits AI Stem Splitter Voice Blender API

OPEN COLLECTION

Kits AI Stem Splitter Voice Conversion API

OPEN COLLECTION

Kits AI Stem Splitter Voice Models API

OPEN COLLECTION

Agent Skills 3

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

Blend voice models into a new voice

AGENT SKILL

Convert a performance to a Kits AI voice

AGENT SKILL

Separate vocals and stems from a track

AGENT SKILL

Arpeggi Labs API pricing

Rate limits

GET requests: 1000 requests per minute
POST requests: 1 requests per minute

Rate-limit details →

Rate Limits 1

Documented rate limits and quota policies.

Arpeggi Labs Rate Limits

2 limits

RATE LIMITS

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

Arpeggi Labs API Rules

62 rules · 59 errors 1 warnings 2 info

SPECTRAL

OpenAPI Overlays 1

Overlays applied on top of this provider's contracts. Each card says who wrote it: a document the provider publishes, or one API Evangelist derived or generated.

Arpeggi Labs Kits Overlay

3 actions · update · arpeggi-labs-kits-openapi.yml

DERIVED

Security Posture 2

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

Arpeggi Labs Authentication

http · 1 scheme

SECURITY

Arpeggi Labs Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Resources

Get Started 3

Portal, sign-up, and the first successful call

DeveloperPortal

DeveloperPortal

GettingStarted

GettingStarted

SignUp

SignUp

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

APIReference

APIReference

Agent Surfaces 3

MCP servers, agent skills, and machine-readable catalogs

LLMsTxt

LLMsTxt

X-MCPServerCandidate

X-MCPServerCandidate

AgentSkill

AgentSkill

Design & Contract 5

Pagination, idempotency, versioning, errors, and events

ErrorCatalog

Conventions

Lifecycle

DataModel

Conformance

Build 2

SDKs, sample code, and the tooling you integrate with

GitHubOrganization

GitHubOrganization

Packages

Packages

Access & Security 2

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Authentication

Authentication

Operate 2

Status, limits, changes, and where to get help

Support

Support

RateLimits

RateLimits

Commercial 3

Pricing, plans, and the legal terms of use

Pricing

Pricing

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

CapabilityMap

CapabilityMap

Overlay

Overlay

Source (apis.yml)

aid: arpeggi-labs
name: Arpeggi Labs
description: 'Arpeggi Labs is the company behind Kits AI, a studio-quality AI music and audio platform for musicians, producers,
  and developers. Kits AI provides voice cloning and conversion, an AI singing generator with 100+ royalty-free artist voice
  models, vocal isolation, stem separation, AI mastering, and a voice-model blender, alongside an ethically sourced "Earn"
  program that pays vocalists to license digital clones of their voice. The Kits AI API exposes these capabilities as asynchronous
  inference jobs over a REST interface at arpeggi.io/api/kits/v1, authenticated with a bearer API key: create a voice conversion,
  vocal separation, stem split, or voice-blend job, then poll for the signed output file URLs. Arpeggi Labs is an a16z portfolio
  company; its earlier product was Arpeggi Studio, a web3 in-browser music creation platform.'
url: https://raw.githubusercontent.com/api-evangelist/arpeggi-labs/refs/heads/main/apis.yml
deliveryModel:
  model: saas
  open_source: false
  commercial: true
  callable_host: true
  label: Hosted service · you call their endpoint
  confidence: high
  source:
  - openapi
  - pricing
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source:
  - authentication
  - rate-limits
  - security
  generated: '2026-11-06'
  method: derived
image: https://kits.ai/opengraph-image
x-type: company
x-source: vc-portfolio
x-backed-by:
- a16z
x-tier: profiled
x-tier-reason: portfolio-lead
specificationVersion: '0.23'
created: '2026-07-17'
modified: '2026-07-18'
x-docs-platform: mintlify
x-docs-platform-confidence: medium
x-docs-platform-checked: 2026-09-19
x-docs-hosting: vercel
tags:
- Company
- Music
- Audio
- Artificial Intelligence
- Voice
- Machine Learning
- Generative AI
- Media
tags_raw:
- Company
- Music
- Audio
- Artificial Intelligence
- Voice
- Machine Learning
- Generative AI
- Media
- Machine-Learning
apis:
- aid: arpeggi-labs:arpeggi-labs-stem-splitter-api
  name: Arpeggi Labs Stem Splitter API
  description: Split an audio track into vocal and instrument stems.
  humanURL: https://docs.kits.ai/api-reference/introduction/getting-started
  baseURL: https://arpeggi.io/api/kits/v1
  tags:
  - Stem Splitter
  properties:
  - type: OpenAPI
    url: openapi/arpeggi-labs-stem-splitter-api-openapi.yml
  - type: Documentation
    url: https://docs.kits.ai
  - type: APIReference
    url: https://docs.kits.ai/api-reference/introduction/getting-started
- aid: arpeggi-labs:arpeggi-labs-vocal-separation-api
  name: Arpeggi Labs Vocal Separation API
  description: Isolate vocals from a mixed audio track.
  humanURL: https://docs.kits.ai/api-reference/introduction/getting-started
  baseURL: https://arpeggi.io/api/kits/v1
  tags:
  - Vocal Separation
  properties:
  - type: OpenAPI
    url: openapi/arpeggi-labs-vocal-separation-api-openapi.yml
  - type: Documentation
    url: https://docs.kits.ai
  - type: APIReference
    url: https://docs.kits.ai/api-reference/introduction/getting-started
- aid: arpeggi-labs:arpeggi-labs-voice-blender-api
  name: Arpeggi Labs Voice Blender API
  description: Blend two to four voice models into a new voice model.
  humanURL: https://docs.kits.ai/api-reference/introduction/getting-started
  baseURL: https://arpeggi.io/api/kits/v1
  tags:
  - Voice Blender
  properties:
  - type: OpenAPI
    url: openapi/arpeggi-labs-voice-blender-api-openapi.yml
  - type: Documentation
    url: https://docs.kits.ai
  - type: APIReference
    url: https://docs.kits.ai/api-reference/introduction/getting-started
- aid: arpeggi-labs:arpeggi-labs-voice-conversion-api
  name: Arpeggi Labs Voice Conversion API
  description: Convert an input performance to a target voice model.
  humanURL: https://docs.kits.ai/api-reference/introduction/getting-started
  baseURL: https://arpeggi.io/api/kits/v1
  tags:
  - Voice Conversion
  properties:
  - type: OpenAPI
    url: openapi/arpeggi-labs-voice-conversion-api-openapi.yml
  - type: Documentation
    url: https://docs.kits.ai
  - type: APIReference
    url: https://docs.kits.ai/api-reference/introduction/getting-started
- aid: arpeggi-labs:arpeggi-labs-voice-models-api
  name: Arpeggi Labs Voice Models API
  description: Browse and retrieve available voice models.
  humanURL: https://docs.kits.ai/api-reference/introduction/getting-started
  baseURL: https://arpeggi.io/api/kits/v1
  tags:
  - Voice Models
  properties:
  - type: OpenAPI
    url: openapi/arpeggi-labs-voice-models-api-openapi.yml
  - type: Documentation
    url: https://docs.kits.ai
  - type: APIReference
    url: https://docs.kits.ai/api-reference/introduction/getting-started
common:
- type: CapabilityMap
  url: capabilities/arpeggi-labs-capability-edges.yml
  name: Arpeggi Labs Business Capability Map
- type: Overlay
  url: overlays/arpeggi-labs-kits-overlay.yaml
- type: DomainSecurity
  url: security/arpeggi-labs-domain-security.yml
- type: Authentication
  url: authentication/arpeggi-labs-authentication.yml
- type: Website
  url: https://kits.ai
- type: DeveloperPortal
  url: https://app.kits.ai
- type: Documentation
  url: https://docs.kits.ai
- type: APIReference
  url: https://docs.kits.ai/api-reference/introduction/getting-started
- type: GettingStarted
  url: https://docs.kits.ai/api-reference/introduction/quick-start
- type: Support
  url: https://help.kits.ai/
- type: Blog
  url: https://www.kits.ai/blog
- type: GitHubOrganization
  url: https://github.com/arpeggi-labs
- type: Pricing
  url: https://app.kits.ai/subscriptions
- type: SignUp
  url: https://app.kits.ai
- type: TermsOfService
  url: https://www.kits.ai/terms-of-service
- type: PrivacyPolicy
  url: https://www.kits.ai/privacy-policy
- type: LLMsTxt
  url: llms/arpeggi-labs-llms.txt
- type: RateLimits
  url: rate-limits/arpeggi-labs-rate-limits.yml
- type: ErrorCatalog
  url: errors/arpeggi-labs-problem-types.yml
- type: Conventions
  url: conventions/arpeggi-labs-conventions.yml
- type: Lifecycle
  url: lifecycle/arpeggi-labs-lifecycle.yml
- type: DataModel
  url: data-model/arpeggi-labs-data-model.yml
- type: Conformance
  url: conformance/arpeggi-labs-conformance.yml
- type: X-MCPServerCandidate
  url: mcp/arpeggi-labs-mcp.yml
  note: 'Renamed from MCPServer 2026-09-03 (roadmap#247): the manifest self-describes as status: candidate — a tool list derived
    from the published API contracts, not an existing server. The scorer already read the manifest and reported mcp_server
    correctly; the MCPServer type was crediting the artifact-type surfaces with a server that does not exist.'
- type: Packages
  url: packages/arpeggi-labs-packages.yml
- type: AgentSkill
  url: skills/_index.yml
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
x-enrichment:
  date: '2026-07-19'
  status: backfilled
  pass: local-v1
  note: backfilled from .gitignore signal + verified work evidence

Arpeggi Labs API — frequently asked questions

Does Arpeggi Labs have an API?

Yes. APIs.io lists 5 APIs from Arpeggi Labs, including Arpeggi Labs Stem Splitter API, Arpeggi Labs Vocal Separation API and Arpeggi Labs Voice Blender API, and 2 more.

Is there an OpenAPI specification for the Arpeggi Labs API?

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

How do I authenticate with the Arpeggi Labs API?

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

Is the Arpeggi Labs API ready for AI agents?

Arpeggi Labs has a Kin Score of 46.0 out of 100 (developing) and an Agent Readiness score of 24.0 (agent-aware), scored by API Evangelist on 2026-11-06.

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