TonePerfect (Pronunciation Assessment API)

TonePerfect offers an AI‑powered pronunciation assessment API for language learning applications. It supports ten languages and provides a single endpoint that returns a detailed score (0‑100) for the whole sentence, each word, and individual sounds, including tone information for Mandarin. The service includes free tier credits, transparent pricing, and robust error handling, making it suitable for developers integrating speech evaluation into apps.

TonePerfect (Pronunciation Assessment API) publishes 3 API contracts indexed on the APIs.io network: Assessment API, Capabilities API, and Utilities API. Tagged areas include Company, AI, Speech, Language-Learning, and Pronunciation.

The TonePerfect (Pronunciation Assessment API) catalog on APIs.io includes 1 JSON-LD context and 1 Spectral governance ruleset.

TonePerfect (Pronunciation Assessment API)’s developer surface includes authentication, pricing, changelog, engineering blog, getting-started guide, documentation, and 22 more developer resources.

🌐 Visit website 📡 Source on GitHub
60.1/100 strong Agent 45/100 agent native Full breakdown ↓
scored 2026-10-09 · rubric v0.23.0
1 published contract
CompanyAISpeechLanguage-LearningPronunciation

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-10-09 · rubric v0.23.0
Composite quality — 60.1/100 · strong
Contract Quality 12.9 / 21
Developer Ergonomics 7.3 / 17
Access Clarity 12.4 / 17
Operational Transparency 4.7 / 11
Contract Governance 8.1 / 10
Discoverability 4.9 / 9
Regulatory Posture 3.4 / 15
Agent readiness — 45/100 · agent native
Machine-Readable Contract 18 / 18
Agentic Access Contract 10 / 10
Documented Reversibility 0 / 6
MCP Server 12 / 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 0 / 6
Protected Resource Metadata 0 / 5
Registration Without a Human 0 / 6
Agentic Commerce Well-Known Document 0 / 5
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/.
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 github.com/api-evangelist/toneperfect: open an issue to ask a question, or submit a pull request to add artifacts. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

APIs 3

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

TonePerfect (Pronunciation Assessment API) Assessment API

The Assessment API from TonePerfect (Pronunciation Assessment API) — 1 operation(s) for assessment.

TonePerfect (Pronunciation Assessment API) Capabilities API

The Capabilities API from TonePerfect (Pronunciation Assessment API) — 1 operation(s) for capabilities.

TonePerfect (Pronunciation Assessment API) Utilities API

The Utilities API from TonePerfect (Pronunciation Assessment API) — 3 operation(s) for utilities.

Pricing Plans 1

Published pricing tiers and plan structures.

Toneperfect Plans Pricing

3 plans

PLANS

Semantic Vocabularies 1

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

Toneperfect Context

11 classes · 62 properties

JSON-LD

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

TonePerfect (Pronunciation Assessment API) API Rules

14 rules · 12 errors 1 warnings 1 info

SPECTRAL

JSON Schema 4

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

Assessment

19 properties

JSON SCHEMA

Capabilities

3 properties

JSON SCHEMA

CompactAssessment

11 properties

JSON SCHEMA

StatusWindow

6 properties

JSON SCHEMA

Security Posture 2

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

Toneperfect Authentication

1 scheme

SECURITY

Toneperfect Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Agentic Access 1

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

Toneperfect Agentic Access

5 operations · 2 acting

5 operations · 2 acting

AGENTIC

Resources

Get Started 2

Portal, sign-up, and the first successful call

Login
Login
 GettingStarted
GettingStarted

Documentation 1

Reference material describing how the API behaves

Documentation
Documentation

Agent Surfaces 2

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess
AgenticAccess
 LLMsTxt
LLMsTxt

Design & Contract 8

Pagination, idempotency, versioning, errors, and events

Spectral
Spectral
 JSONLD
JSONLD
 Vocabulary
Vocabulary
 DataModel
DataModel
 Idempotency
Idempotency
 Conventions
Conventions
 ErrorCatalog
ErrorCatalog
 Conformance
Conformance

Scroll for all 8

Build 2

SDKs, sample code, and the tooling you integrate with

Packages
Packages
 SDKs
SDKs

Access & Security 3

Authentication, authorization, and security posture

Authentication
Authentication
 Security
Security
 DomainSecurity
DomainSecurity

Operate 2

Status, limits, changes, and where to get help

StatusPage
StatusPage
 ChangeLog
ChangeLog

Commercial 4

Pricing, plans, and the legal terms of use

Plans
Plans
 TermsOfService
TermsOfService
 PrivacyPolicy
PrivacyPolicy
 Pricing
Pricing

Company 2

The organization behind the API

Blog
Blog
 Website
Website

Other 2

Properties that don't map to a standard resource type

Hosts
Hosts
 Vendors
Vendors

Source (apis.yml)

apis.yml Raw ↑ 
aid: toneperfect
name: TonePerfect (Pronunciation Assessment API)
image: https://api.toneperfect.app/static/og-image.png
description: TonePerfect offers an AI‑powered pronunciation assessment API for language learning applications. It supports
  ten languages and provides a single endpoint that returns a detailed score (0‑100) for the whole sentence, each word, and
  individual sounds, including tone information for Mandarin. The service includes free tier credits, transparent pricing,
  and robust error handling, making it suitable for developers integrating speech evaluation into apps.
url: https://raw.githubusercontent.com/api-evangelist/toneperfect/refs/heads/main/apis.yml
x-type: company
x-source: harvest:new-submission
x-tier: profiled
x-tier-reason: enrichment pass 2026-10-08 (modular-v1; was harvest)
specificationVersion: '0.20'
created: '2026-10-08'
modified: '2026-10-08'
tags:
- Company
- AI
- Speech
- Language-Learning
- Pronunciation
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: AgenticAccess
  url: agentic-access/toneperfect-agentic-access.yml
- type: Plans
  url: plans/toneperfect-plans-pricing.yml
- type: Spectral
  url: rules/toneperfect-rules.yml
- type: JSONLD
  url: json-ld/toneperfect-context.jsonld
- type: Vocabulary
  url: vocabulary/toneperfect-vocabulary.yml
- type: DataModel
  url: data-model/toneperfect-data-model.yml
- type: Idempotency
  url: conventions/toneperfect-conventions.yml
- type: Conventions
  url: conventions/toneperfect-conventions.yml
- type: Authentication
  url: authentication/toneperfect-authentication.yml
- type: ErrorCatalog
  url: errors/toneperfect-problem-types.yml
- type: Conformance
  url: conformance/toneperfect-conformance.yml
- type: LLMsTxt
  url: llms/toneperfect-llms.txt
- type: Hosts
  url: hosts/toneperfect-hosts.yml
- type: Vendors
  url: vendors/toneperfect-vendors.yml
- type: Packages
  url: packages/toneperfect-packages.yml
- type: TermsOfService
  url: https://api.toneperfect.app/terms/
- type: StatusPage
  url: https://api.toneperfect.app/status/
- type: Security
  url: https://api.toneperfect.app/security/
- type: SDKs
  url: https://api.toneperfect.app/sdk/
- type: PrivacyPolicy
  url: https://api.toneperfect.app/privacy/
- type: Pricing
  url: https://api.toneperfect.app/pricing/
- type: Login
  url: https://api.toneperfect.app/login
- type: ChangeLog
  url: https://api.toneperfect.app/changelog/
- type: Blog
  url: https://api.toneperfect.app/blog/
- type: GettingStarted
  url: https://api.toneperfect.app/quickstart/
- type: DomainSecurity
  url: security/toneperfect-domain-security.yml
- type: Website
  url: https://api.toneperfect.app
- type: Documentation
  url: https://api.toneperfect.app/docs
apis:
- aid: toneperfect:toneperfect-assessment-api
  name: TonePerfect (Pronunciation Assessment API) Assessment API
  description: The Assessment API from TonePerfect (Pronunciation Assessment API) — 1 operation(s) for assessment.
  humanURL: https://api.toneperfect.app/docs
  tags:
  - Assessment
  properties:
  - type: OpenAPI
    url: openapi/toneperfect-assessment-api-openapi.yml
  - type: JSONSchema
    url: json-schema/toneperfect-assessment-schema.json
  - type: JSONSchema
    url: json-schema/toneperfect-capabilities-schema.json
  - type: JSONSchema
    url: json-schema/toneperfect-compact-assessment-schema.json
  - type: JSONSchema
    url: json-schema/toneperfect-status-window-schema.json
- aid: toneperfect:toneperfect-capabilities-api
  name: TonePerfect (Pronunciation Assessment API) Capabilities API
  description: The Capabilities API from TonePerfect (Pronunciation Assessment API) — 1 operation(s) for capabilities.
  humanURL: https://api.toneperfect.app/docs
  tags:
  - Capabilities
  properties:
  - type: OpenAPI
    url: openapi/toneperfect-capabilities-api-openapi.yml
  - type: JSONSchema
    url: json-schema/toneperfect-assessment-schema.json
  - type: JSONSchema
    url: json-schema/toneperfect-capabilities-schema.json
  - type: JSONSchema
    url: json-schema/toneperfect-compact-assessment-schema.json
  - type: JSONSchema
    url: json-schema/toneperfect-status-window-schema.json
- aid: toneperfect:toneperfect-utilities-api
  name: TonePerfect (Pronunciation Assessment API) Utilities API
  description: The Utilities API from TonePerfect (Pronunciation Assessment API) — 3 operation(s) for utilities.
  humanURL: https://api.toneperfect.app/docs
  tags:
  - Utilities
  properties:
  - type: OpenAPI
    url: openapi/toneperfect-utilities-api-openapi.yml
  - type: JSONSchema
    url: json-schema/toneperfect-assessment-schema.json
  - type: JSONSchema
    url: json-schema/toneperfect-capabilities-schema.json
  - type: JSONSchema
    url: json-schema/toneperfect-compact-assessment-schema.json
  - type: JSONSchema
    url: json-schema/toneperfect-status-window-schema.json
x-submission-notes: Solo founder, gmail contact. Domain toneperfect.app; submitter asks for one API only.
x-submission-probe: root/docs 200; openapi.json 200 (OpenAPI 3.1); llms.txt 200; soft-404 clean (404)
x-submitted-by: nicolas.maissouradze@gmail.com (apis.io/add, 2026-10-07T07:41:08.244Z)
x-enrichment:
  date: '2026-10-08'
  status: enriched
  artifacts_added: 19
  pass: modular-v1
  engine: identity=local,contract=local,surfaces=local,docs=local,regulatory=local

Work with this as data

Every provider here is available over the APIs.io API and to AI agents over MCP.

MCP server

One button, every client — Claude, Cursor, VS Code and the rest.

https://apis.io/mcp

Tools for providers

9 MCP tools reach this
  • find_providersBrowse and filter every provider in the catalog.
  • get_provider_artifactsEvery artifact this provider publishes, grouped by type.
  • get_provider_operationsEvery operation across all of their OpenAPIs — one call instead of parsing every spec.
  • get_provider_toolsEvery MCP tool they ship, with the operation each wraps.
  • get_provider_evidenceHow each part of their score was established. Free — the basis for a claim should not sit behind it.
  • get_provider_ratingPRO — composite, band, trend and facet scores.
  • apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
  • resolveTurn a domain, URL or GitHub org into the provider it belongs to.
  • find_cohortsEvery scored population of providers in the catalog.
All 92 tools →

Call it yourself

curl for this page
This provider 
curl "https://apis.io/api/v1/providers/toneperfect"
All providers 
curl "https://apis.io/api/v1/providers?limit=25"
Every operation they expose 
curl "https://apis.io/api/v1/providers/toneperfect/operations?limit=25"
How their score was established 
curl "https://apis.io/api/v1/providers/toneperfect/evidence"

Discovery needs no key. Ratings and market analysis are Pro.

Get an API key

Free tier, no form to fill in. Signing in shares your email address with us — we store it to create your key and to recognise you if you sign in with another provider. See our Privacy Policy and Terms.

GitHub Google LinkedIn

A second provider on the same verified email joins the account you already have.