IBM Watson Text to Speech

Name: IBM Watson Text to Speech API
Brand: IBM Watson Text to Speech
Availability: InStock

★ Only Publicly Available OpenAPI DocumentAI/MLSpeechbearer6 EndpointsREST

For Agents

Synthesise text into spoken audio in many languages and voices via IBM Watson — list voices, fetch pronunciations, and manage custom pronunciation models.

Connect the IBM Watson Text to Speech to your agent

Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the IBM Watson Text to Speech, or any other public or private API you need. You set the rules, the agent never sees your credentials, and every call is logged.

Install Jentic One Beta (Self-Hosted)

Jentic One Host machine

# On the machine that will host your Jentic One instance:
curl -fsSL https://raw.githubusercontent.com/jentic/jentic-one/main/tools/install.sh | sh

Agent machine

# On the machine where your agent runs (keep this separate from the instance):
curl -fsSL https://raw.githubusercontent.com/jentic/jentic-one/main/tools/install.sh | sh
jentic register       # connects your agent to your Jentic One instance

Jentic One is in public beta. The setup above keeps your agent separate from the instance, which is what you want before using real credentials: an agent running as the same OS user as Jentic One can read its stored keys directly. Just evaluating? A single local install is fine to start. See the secure deployment guide for the tiers.

Capabilities

What an agent can do with IBM Watson Text to Speech API.

Synthesise text into audio via /v1/synthesize

List the catalogue of available voices via /v1/voices

Get the details of a specific voice via /v1/voices/{voice}

Look up the phonetic pronunciation of a word via /v1/pronunciation

GET STARTED

Start building with IBM Watson Text to Speech API

Explore with Jentic

View OpenAPI Document

Jentic publishes the only available OpenAPI document for IBM Watson Text to Speech, keeping it validated and agent-ready.

Jentic publishes the only available OpenAPI specification for IBM Watson Text to Speech, keeping it validated and agent-ready. IBM Watson Text to Speech synthesises text into natural-sounding audio across multiple languages, dialects, and named voices, and is widely used to add spoken output to IVR systems, accessibility features, and assistants. The API exposes the synthesis endpoint, the catalogue of available voices, a pronunciation lookup, and a customizations resource for managing per-tenant pronunciation overrides.

Use Cases

Patterns agents use IBM Watson Text to Speech API for, with concrete tasks.

★ IVR Prompt Generation

Render IVR prompts as audio at deploy time or on demand by POSTing the prompt text to /v1/synthesize and storing the returned audio. Watson supports multiple languages and named voices, so the same pipeline can produce localised prompts without a voice actor and without redeploying the IVR system.

POST the text 'Press one for billing' to /v1/synthesize with voice en-US_AllisonV3Voice and accept audio/mp3, then save the binary response as billing.mp3.

Accessibility Read-Aloud

Add a spoken read-aloud feature to a web or mobile app by sending the visible text to /v1/synthesize and streaming the returned audio to the client. Watson handles the speech generation and a list of voices is available via /v1/voices, which lets users pick a preferred voice and language.

Synthesise the body of an article via /v1/synthesize using the user's selected voice from /v1/voices and stream the audio to the browser.

Custom Pronunciation Models

Create a customization under /v1/customizations to teach Watson how to pronounce industry-specific terms, brand names, or product SKUs. Once a customization is in place, calls to /v1/synthesize can reference it so the synthesised audio uses the corrected pronunciation.

Create a customization for the en-US base model, add an entry mapping the brand name 'Acme' to its phonetic spelling, and synthesise a sentence that uses it.

AI Agent Voice Output

An AI agent uses Jentic to add a spoken-output channel — for example, generating audio briefings or accessibility output — without managing an IBM Cloud IAM token directly. The agent searches by intent, loads the synthesise schema, and posts the text. Typical agent integration is under one hour because the synthesise surface is one operation.

Search Jentic for 'synthesise text to speech with IBM Watson', load the /v1/synthesize schema, and produce an MP3 of the daily briefing text.

Key Endpoints

6 endpoints — jentic publishes the only available openapi specification for ibm watson text to speech, keeping it validated and agent-ready.

METHOD

PATH

DESCRIPTION

POST

/v1/synthesize

Synthesise text into audio

GET

/v1/voices

List available voices

GET

/v1/voices/{voice}

Get details of a specific voice

GET

/v1/pronunciation

Get the pronunciation of a word

GET

/v1/customizations

List custom pronunciation models

POST

/v1/synthesize

Synthesise text into audio

GET

/v1/voices

List available voices

GET

/v1/voices/{voice}

Get details of a specific voice

GET

/v1/pronunciation

Get the pronunciation of a word

GET

/v1/customizations

List custom pronunciation models

Why though Jentic?

Three things that make agents converge on Jentic-routed access.

Credential isolation

IBM Cloud IAM bearer tokens are stored encrypted in the Jentic vault. Agents call Watson Text to Speech via scoped Jentic credentials and never see the raw IAM token in their context.

Intent-based discovery

Agents search by intent (for example 'synthesise text to speech with IBM Watson') and Jentic returns the /v1/synthesize operation with its parameter schema, so the agent does not have to read the Watson API reference.

Time to first call

Direct Watson TTS integration: 1-2 days for IAM token exchange, audio handling, and voice selection. Through Jentic: under one hour — search, load schema, execute.

Related APIs

Alternatives and complements available in the Jentic catalogue.

Alternative

ElevenLabs API

ElevenLabs offers state-of-the-art neural voice cloning and synthesis; Watson focuses on enterprise-grade multilingual TTS.

Choose ElevenLabs for highly expressive or cloned voices. Choose Watson when the deployment is on IBM Cloud or needs the standard Watson voice set.

Alternative

OpenAI API

OpenAI's audio endpoints provide TTS alongside chat and whisper; Watson is a dedicated speech service.

Choose OpenAI when the agent already uses OpenAI for other modalities. Choose Watson when standardising on IBM Cloud for speech synthesis.

Complementary

Deepgram API

Deepgram is a speech-to-text service that pairs with Watson TTS to build a full conversational stack.

Use Deepgram for transcription on the input side. Use Watson TTS for spoken output on the response side.

FAQs

Specific to using IBM Watson Text to Speech API through Jentic.

Why is there no official OpenAPI spec for IBM Watson Text to Speech?

IBM does not publish an OpenAPI specification for Watson Text to Speech. Jentic generates and maintains this spec so that AI agents and developers can call IBM Watson Text to Speech via structured tooling. It is validated against the live API and kept up to date. Get started at https://app.jentic.com/sign-up.

What authentication does the IBM Watson Text to Speech API use?

The API uses HTTP bearer authentication with an IBM Cloud IAM token. Through Jentic, the IAM credentials are stored in the Jentic vault and the agent calls Watson via a scoped Jentic credential, never seeing the raw token.

Can I synthesise text into an MP3 with this API?

Yes. POST the text and voice to /v1/synthesize and set the Accept header to audio/mp3. The endpoint also supports other formats including audio/wav and audio/ogg, and the choice of voice is constrained to the names returned by /v1/voices.

How do I list the available voices?

GET /v1/voices returns the full set of named voices, including their language and gender. GET /v1/voices/{voice} returns the metadata for a specific voice, which is useful for surfacing voice attributes in a settings UI.

How do I generate audio through Jentic?

Search Jentic for 'synthesise text to speech with IBM Watson', load the /v1/synthesize schema, and execute with the text and voice. Install the SDK with pip install jentic and use the async search, load, execute pattern from Python.

What are the rate limits for the IBM Watson Text to Speech API?

Watson services apply IBM Cloud account-level rate limits rather than a published per-endpoint limit. Treat 429 responses as backpressure, retry with exponential backoff, and pre-render high-volume static prompts ahead of time.