FreJun Teler

FreJun Teler is a developer-first programmable voice/telephony API (CPaaS) that handles carriers, phone numbers, and real-time audio streaming so developers can connect AI models (STT/LLM/TTS) to live phone calls. It offers real-time bidirectional audio over WebSocket (L16/8000 Hz, sub-250ms latency) and programmable SIP trunking, with webhook event delivery and official Python (teler) and Node (@frejun/teler) SDKs.

FreJun Teler publishes 1 API on the APIs.io network: Teler Voice API. Tagged areas include programmable voice API, voice AI infrastructure, CPaaS, SIP Trunking, and telephony API.

The FreJun Teler catalog on APIs.io includes 1 event-driven AsyncAPI specification.

FreJun Teler’s developer surface includes documentation, API reference, engineering blog, pricing, signup flow, authentication, sandbox, and 25 more developer resources.

🌐 Visit website 📡 Source on GitHub
48.3/100 developing Agent 47/100 agent ready Full breakdown ↓
scored 2026-09-15 · rubric v0.22.0
1 APIs 1 MCP Servers
programmable voice APIvoice AI infrastructureCPaaSSIP Trunkingtelephony APIreal-time media streamingWebSocket audioCall Automationconversational AI infrastructure

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-09-15 · rubric v0.22.0
Composite quality — 48.3/100 · developing
Contract Quality 11.3 / 19
Developer Ergonomics 8.5 / 15
Access Clarity 6.7 / 15
Operational Transparency 3.6 / 10
Contract Governance 0.4 / 9
Discoverability 5.7 / 8
Regulatory Posture 5.2 / 15
Create-or-Update Ergonomics 0.0 / 10
Agent readiness — 47/100 · agent ready
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 7 / 7
Rate-Limit Signaling 7 / 7
Typed Event Surface 6 / 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 6 / 6
Protected Resource Metadata 5 / 5
Registration Without a Human 6 / 6
Agentic Commerce Well-Known Document 0 / 5
Regulatory Posture applies to this provider. Its tags matched the Telecommunications 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/.
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/frejun-teler: 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 1

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

Teler Voice API

Programmable voice/telephony API. Places and controls live voice calls (initiate, play audio, DTMF, transfer, hangup), streams bidirectional call audio to AI agents over a WebSo...

MCP Servers 1

Model Context Protocol servers that expose these APIs to AI agents.

FreJun Teler MCP Server

MCP SERVER

Pricing Plans 1

Published pricing tiers and plan structures.

Frejun Teler Plans Pricing

0 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Frejun Teler Rate Limits

0 limits

RATE LIMITS

Event Specifications 1

AsyncAPI definitions for this provider's event-driven and streaming APIs.

Frejun Teler Webhooks

ASYNCAPI

Security Posture 2

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

Frejun Teler Authentication

apiKey · 1 scheme

SECURITY

Frejun Teler Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Resources

Get Started 4

Portal, sign-up, and the first successful call

DeveloperPortal
DeveloperPortal
 SignUp
SignUp
 Login
Login
 Sandbox
Sandbox

Documentation 2

Reference material describing how the API behaves

Documentation
Documentation
 APIReference
APIReference

Agent Surfaces 4

MCP servers, agent skills, and machine-readable catalogs

LLMsTxt
LLMsTxt
 WellKnown
WellKnown
 MCPServer
MCPServer
 AgentSkill
AgentSkill

Design & Contract 7

Pagination, idempotency, versioning, errors, and events

Conventions
Conventions
 Lifecycle
Lifecycle
 Conformance
Conformance
 Components
Components
 Webhooks
Webhooks
 DataModel
DataModel
 ErrorCatalog
ErrorCatalog

Scroll for all 7

Build 3

SDKs, sample code, and the tooling you integrate with

GitHubOrganization
GitHubOrganization
 Packages
Packages
 SDKs
SDKs

Access & Security 2

Authentication, authorization, and security posture

Authentication
Authentication
 DomainSecurity
DomainSecurity

Operate 3

Status, limits, changes, and where to get help

StatusPage
StatusPage
 Deprecation
Deprecation
 RateLimits
RateLimits

Commercial 4

Pricing, plans, and the legal terms of use

Pricing
Pricing
 TermsOfService
TermsOfService
 PrivacyPolicy
PrivacyPolicy
 Plans
Plans

Company 2

The organization behind the API

Website
Website
 Blog
Blog

Other 1

Properties that don't map to a standard resource type

Overlay
Overlay

Source (apis.yml)

apis.yml Raw ↑ 
aid: frejun-teler
name: FreJun Teler
description: FreJun Teler is a developer-first programmable voice/telephony API (CPaaS) that handles carriers, phone numbers,
  and real-time audio streaming so developers can connect AI models (STT/LLM/TTS) to live phone calls. It offers real-time
  bidirectional audio over WebSocket (L16/8000 Hz, sub-250ms latency) and programmable SIP trunking, with webhook event delivery
  and official Python (teler) and Node (@frejun/teler) SDKs.
type: Index
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/apis-json-logo.jpg
url: https://raw.githubusercontent.com/api-evangelist/frejun-teler/refs/heads/main/apis.yml
created: '2026-09-15'
modified: '2026-09-15'
tags:
- programmable voice API
- voice AI infrastructure
- CPaaS
- SIP Trunking
- telephony API
- real-time media streaming
- WebSocket audio
- Call Automation
- conversational AI infrastructure
tags_raw:
- programmable voice API
- voice AI infrastructure
- CPaaS
- SIP trunking
- telephony API
- real-time media streaming
- WebSocket audio
- call automation
- conversational AI infrastructure
apis:
- name: Teler Voice API
  image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/apis-json-logo.jpg
  description: Programmable voice/telephony API. Places and controls live voice calls (initiate, play audio, DTMF, transfer,
    hangup), streams bidirectional call audio to AI agents over a WebSocket media channel, and provisions programmable SIP
    trunking (trunks, IP ACLs, virtual numbers). REST resources for calls, voice apps, virtual numbers, SIP trunks/calls,
    webhook events, recordings and secrets use cursor pagination. Served from https://api.frejun.ai and authenticated with
    an x-api-key header. Backed by official Python (teler) and Node (@frejun/teler) SDKs.
  humanURL: https://frejun.com/docs/teler/
  baseURL: https://api.frejun.ai
  tags:
  - programmable voice API
  - voice AI infrastructure
  - CPaaS
  - SIP Trunking
  - telephony API
  - real-time media streaming
  - WebSocket audio
  - Call Automation
  - conversational AI infrastructure
  tags_raw:
  - programmable voice API
  - voice AI infrastructure
  - CPaaS
  - SIP trunking
  - telephony API
  - real-time media streaming
  - WebSocket audio
  - call automation
  - conversational AI infrastructure
  properties:
  - type: OpenAPI
    url: openapi/frejun-teler-openapi.json
  - type: Documentation
    url: https://frejun.com/docs/teler/
  - type: APIReference
    url: https://api.frejun.ai/redoc
  - type: Authentication
    url: authentication/frejun-teler-authentication.yml
  - type: Conventions
    url: conventions/frejun-teler-conventions.yml
  - type: ErrorCatalog
    url: errors/frejun-teler-problem-types.yml
  - type: DataModel
    url: data-model/frejun-teler-data-model.yml
  - type: Webhooks
    url: asyncapi/frejun-teler-webhooks.yml
  - type: Overlay
    url: overlays/frejun-teler-openapi-overlay.yaml
common:
- type: Website
  url: https://www.frejun.ai
- type: DeveloperPortal
  url: https://frejun.com/docs/teler/
- type: Documentation
  url: https://frejun.com/docs/teler/
- type: APIReference
  url: https://api.frejun.ai/redoc
- type: Blog
  url: https://frejun.com/teler-blog/
- type: Pricing
  url: https://frejun.com/teler/pricing/
- type: SignUp
  url: https://platform.frejun.ai/signup
- type: Login
  url: https://platform.frejun.ai/login
- type: TermsOfService
  url: https://frejun.com/terms/
- type: PrivacyPolicy
  url: https://frejun.com/privacy-policy/
- type: GitHubOrganization
  url: https://github.com/frejun-tech
- type: StatusPage
  url: https://frejun.statuspage.io
- type: LLMsTxt
  url: https://www.frejun.ai/llms.txt
- type: WellKnown
  url: well-known/frejun-teler-well-known.yml
- type: Authentication
  url: authentication/frejun-teler-authentication.yml
- type: DomainSecurity
  url: security/frejun-teler-domain-security.yml
- type: Conventions
  url: conventions/frejun-teler-conventions.yml
- type: Lifecycle
  url: lifecycle/frejun-teler-lifecycle.yml
- type: Deprecation
  url: lifecycle/frejun-teler-lifecycle.yml
- type: Conformance
  url: conformance/frejun-teler-conformance.yml
- type: MCPServer
  url: mcp/frejun-teler-mcp.yml
- type: AgentSkill
  url: skills/_index.yml
- type: Packages
  url: packages/frejun-teler-packages.yml
- type: SDKs
  url: packages/frejun-teler-packages.yml
- type: Components
  url: components/frejun-teler-components.yml
- type: Webhooks
  url: asyncapi/frejun-teler-webhooks.yml
- type: DataModel
  url: data-model/frejun-teler-data-model.yml
- type: ErrorCatalog
  url: errors/frejun-teler-problem-types.yml
- type: Overlay
  url: overlays/frejun-teler-openapi-overlay.yaml
- type: Sandbox
  url: sandbox/frejun-teler-sandbox.yml
- type: RateLimits
  url: rate-limits/frejun-teler-rate-limits.yml
- type: Plans
  url: plans/frejun-teler-plans-pricing.yml
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
x-enrichment:
  date: '2026-09-15'
  status: enriched
  artifacts_added: 24
  pass: local-v3

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