Listnr

Listnr AI is a text-to-speech and AI voice platform offering 1,000+ ultra-realistic voices across 142+ languages and accents, used for voiceovers, podcasts, and text-to-video. Beyond the web app, Listnr exposes a documented public Text-to-Speech API (base https://bff.listnr.tech/api/tts/v1) that converts SSML text or article URLs into MP3/WAV audio synchronously or asynchronously, lists available voices, and reports async job status. API keys are generated from the Listnr dashboard at voices.listnr.tech and passed via an x-listnr-token header.

Listnr publishes 3 API contracts indexed on the APIs.io network: Agent API, Billing API, and Catalog API. Tagged areas include Artificial Intelligence, Text-to-Speech, Voice, Speech Synthesis, and Audio.

The Listnr catalog on APIs.io includes 1 Spectral governance ruleset.

Listnr’s developer surface includes pricing, engineering blog, authentication, documentation, signup flow, and 8 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

34.4/100 thin ▬ flat Agent 40/100 agent native Front door AI 6/6 dominant Heartbeat 100/100 alive saas Full breakdown ↓
scored 2026-11-13 · rubric v0.28.0 · Show this score on your site →

AccessFreemiumSelf serve⚡ Free to try

1 published contract

Artificial Intelligence Text-to-Speech Voice Speech Synthesis Audio Voiceover

Kin Score

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

Composite quality — 34.4/100 · thin

Contract Quality 9.7 / 19

Developer Ergonomics 4.8 / 15

Access Clarity 5.9 / 15

Operational Transparency 1.2 / 10

Contract Governance 1.2 / 9

Discoverability 5.0 / 8

Regulatory Posture 0.8 / 15

Create-or-Update Ergonomics 0.0 / 10

Agent readiness — 40/100 · agent native

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 0 / 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 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 0 / 5

Pagination 0 / 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 Ask about this →
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0 Ask about this →
Request/Response Examples +7 pts — share of operations carrying request/response examples; else an Examples / Code Samples link Ask about this →
Registration Without a Human +6 pts — a `registration_endpoint` in the served RFC 8414 / OIDC discovery document 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 →
Documented Reversibility +6 pts — a reversal operation in the contract, graded up when a window is documented too 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):

Developer Ergonomics scores 32.1 — up to +13.6 composite points Ask about this →
Contract Quality scores 51.5 — up to +12.1 composite points Ask about this →
Access Clarity scores 39.4 — up to +12.1 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/listnr/apis.yml: open an issue on github.com/api-evangelist/listnr 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 3

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

Listnr Agent API

Discovery and authentication hints

Listnr Billing API

Published plan and credit limits

Listnr Catalog API

Tools and marketing pages

Open Collections 4

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

Listnr Text-to-Speech Jobs API

OPEN COLLECTION

Listnr Jobs Text-to-Speech API

OPEN COLLECTION

Listnr Text-to-Speech Jobs Voices API

OPEN COLLECTION

Listnr Text-to-Speech API

OPEN COLLECTION

Listnr API pricing

Prices published by Listnr, read 2026-10-07 from listnr.ai/pricing.

Plan	Price
Free	$0 per month Includes: 1,000 credits to start; Preview 1,000+ AI voices; 142+ languages and accents; Listnr Studio access
Individual	$19 per month Includes: 20,000 credits/month (~2 hours), 50GB storage, 50 videos/month, unlimited downloads, commercial righ
Solo	$39 per month Includes: 50,000 credits/month (~5 hours), 100GB storage, 150 videos/month
Agency	$99 per month Includes: 250,000 credits/month (~25 hours), 250GB storage, 250 videos/month
Custom pricing / Enterprise	Contact us Includes: Seat-based licenses, custom credit volumes, dedicated API throughput, SSO, volume pricing

Plan details, limits and sources →

Rate limits

Text-to-Speech API Requests: not published requests
Monthly Voice-Generation Credits: per plan credits
Asynchronous Job Processing: queue-bound jobs

Compiled by API Evangelist, not yet checked against Listnr's documentation. Rate-limit details →

Pricing Plans 1

Published pricing tiers and plan structures.

Listnr Plans Pricing

5 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Listnr Rate Limits

3 limits

RATE LIMITS

FinOps 1

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

Listnr Finops

FINOPS

Spectral Rules 1

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

Listnr API Rules

61 rules · 59 error-severity 1 warn-severity 1 info-severity

SPECTRAL

Security Posture 2

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

Listnr Authentication

apiKey · 1 scheme

SECURITY

Listnr Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Agentic Access (API Evangelist recommendations) 1

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

Listnr Agentic Access

8 operations · 2 acting

AGENTIC

Resources

Get Started 1

Portal, sign-up, and the first successful call

SignUp

SignUp

Documentation 1

Reference material describing how the API behaves

Documentation

Documentation

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

AgenticAccess

Build 1

SDKs, sample code, and the tooling you integrate with

GitHubOrganization

GitHubOrganization

Access & Security 2

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Authentication

Authentication

Operate 1

Status, limits, changes, and where to get help

RateLimits

RateLimits

Commercial 3

Pricing, plans, and the legal terms of use

Pricing

Pricing

Plans

Plans

FinOps

FinOps

Company 3

The organization behind the API

Blog

Blog

LinkedIn

Website

Website

Source (apis.yml)

aid: listnr
url: https://raw.githubusercontent.com/api-evangelist/listnr/refs/heads/main/apis.yml
name: Listnr
kind: company
description: Listnr AI is a text-to-speech and AI voice platform offering 1,000+ ultra-realistic voices across 142+ languages
  and accents, used for voiceovers, podcasts, and text-to-video. Beyond the web app, Listnr exposes a documented public Text-to-Speech
  API (base https://bff.listnr.tech/api/tts/v1) that converts SSML text or article URLs into MP3/WAV audio synchronously or
  asynchronously, lists available voices, and reports async job status. API keys are generated from the Listnr dashboard at
  voices.listnr.tech and passed via an x-listnr-token header.
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: freemium
  onboarding: self-serve
  trial: false
  try_now: true
  public: false
  gated: none
  gated_source:
  - onboarding
  label: Freemium · Self-serve signup
  confidence: medium
  source:
  - plans
  - authentication
  - security
  generated: '2026-11-13'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/listnr.png
tags:
- Artificial Intelligence
- Text-to-Speech
- Voice
- Speech Synthesis
- Audio
- Voiceover
tags_raw:
- AI
- Text to Speech
- TTS
- Voice
- Speech Synthesis
- Audio
- Voiceover
created: '2026-07-11'
modified: '2026-10-06'
specificationVersion: '0.23'
apis:
- aid: listnr:listnr-agent-api
  name: Listnr Agent API
  description: Discovery and authentication hints
  humanURL: https://listnr.ai/text-to-speech-api
  baseURL: https://bff.listnr.tech/api/tts/v1
  tags:
  - Agents
  tags_raw:
  - Agent
  properties:
  - type: OpenAPI
    url: openapi/listnr-agent-api-openapi.yml
  - type: Documentation
    url: https://listnr.ai/text-to-speech-api
  - type: APIReference
    url: https://github.com/team-listnr/text-to-speech-api
  - type: PostmanCollection
    url: collections/listnr.postman_collection.json
  - type: OpenCollection
    url: collections/listnr.opencollection.json
- aid: listnr:listnr-billing-api
  name: Listnr Billing API
  description: Published plan and credit limits
  humanURL: https://listnr.ai/text-to-speech-api
  baseURL: https://bff.listnr.tech/api/tts/v1
  tags:
  - Billing
  properties:
  - type: OpenAPI
    url: openapi/listnr-billing-api-openapi.yml
  - type: Documentation
    url: https://listnr.ai/text-to-speech-api
  - type: APIReference
    url: https://github.com/team-listnr/text-to-speech-api
  - type: PostmanCollection
    url: collections/listnr.postman_collection.json
  - type: OpenCollection
    url: collections/listnr.opencollection.json
- aid: listnr:listnr-catalog-api
  name: Listnr Catalog API
  description: Tools and marketing pages
  humanURL: https://listnr.ai/text-to-speech-api
  baseURL: https://bff.listnr.tech/api/tts/v1
  tags:
  - Catalog
  properties:
  - type: OpenAPI
    url: openapi/listnr-catalog-api-openapi.yml
  - type: Documentation
    url: https://listnr.ai/text-to-speech-api
  - type: APIReference
    url: https://github.com/team-listnr/text-to-speech-api
  - type: PostmanCollection
    url: collections/listnr.postman_collection.json
  - type: OpenCollection
    url: collections/listnr.opencollection.json
common:
- type: Pricing
  url: https://listnr.ai/pricing
- url: https://listnr.ai/blog
  type: Blog
- type: AgenticAccess
  url: agentic-access/listnr-agentic-access.yml
- type: DomainSecurity
  url: security/listnr-domain-security.yml
- type: Authentication
  url: authentication/listnr-authentication.yml
- type: LinkedIn
  url: https://www.linkedin.com/company/listnr
- type: GitHubOrganization
  url: https://github.com/team-listnr
- type: Website
  url: https://listnr.ai
- type: Documentation
  url: https://github.com/team-listnr/text-to-speech-api
- type: SignUp
  url: https://voices.listnr.tech
- type: Plans
  url: plans/listnr-plans-pricing.yml
- type: RateLimits
  url: rate-limits/listnr-rate-limits.yml
- type: FinOps
  url: finops/listnr-finops.yml
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com

Listnr API — frequently asked questions

Does Listnr have an API?

Yes. APIs.io lists 3 APIs from Listnr, including Listnr Agent API, Listnr Billing API and Listnr Catalog API.

Is there an OpenAPI specification for the Listnr API?

Yes. APIs.io indexes 3 OpenAPI specifications for Listnr, each linked for download from this page.

How do I authenticate with the Listnr API?

Listnr documents its authentication (apiKey · 1 scheme). The details are profiled on APIs.io as Listnr Authentication.

How much does the Listnr API cost?

Listnr publishes its prices; its Free plan is $0 per month as of 2026-10-07. APIs.io lists 5 pricing plans for Listnr, with each plan's price, limits and inclusions under Pricing on this page.

Is the Listnr API ready for AI agents?

Listnr has a Kin Score of 34.4 out of 100 (thin) and an Agent Readiness score of 39.5 (agent-native), scored by API Evangelist on 2026-11-13.

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