Text to Speech API & YouTube Transcript API

Grammar checking, AI text generation, text-to-speech and YouTube transcripts through one normalized interface.

10 endpoints · 1 credit = $0.001. Each endpoint has its own credit cost, listed below. Calls that fail because of a service error are refunded.

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AxioAPI Studio · Content & Text Processing

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Text

Video

Speech

Văn Bản Gốc (Original)

—

Bản Tối Ưu Bởi AI (Enhanced)

—

Need YouTube video captions? Try our free transcript extractor.

Transcript Tool YouTube Workbench →

Ready ?

No request yet. Run a test to see the actual response.

What you can build with the text to speech API

The text to speech API turns up to 2,000 characters into audio with a choice of voices, alongside grammar checking, AI text generation and YouTube transcripts behind one set of REST endpoints. Try them in the tool above, then call the same operations from your app.

Check grammar in your editor or CMS

Send up to 50,000 characters and a language to get grammar and spelling suggestions back.

POST /api/v1/grammar/check

Turn text into audio

Convert up to 2,000 characters to speech with a voice of your choice, then download the audio file by job ID.

POST /api/v1/audio/tts

Get a YouTube transcript

Fetch the transcript and tags of a video by ID for summaries, search or content repurposing.

GET /api/v1/videos/{video}/transcript

Try it free, no account needed: YouTube transcript extractor · Text to speech

How the text to speech API works

1
Choose the operation

Grammar, text generation, transcript, tags, prompt topics or text to speech. Each has its own inputs.
2
Call the endpoint

For example POST /api/v1/audio/tts with text and a voice. List voices first with GET /api/v1/tts/voices.
3
Fetch the result

Each text-to-speech call returns a job ID: use it to check the job, download the audio artifact or delete the stored result.

Try the Content & Text Processing API with your own account

New accounts receive 200 credits after verification, enough for about 2000 calls to "List AI prompt topics catalog".

Get 200 free credits Read the docs

Using Content & Text Processing

Choose grammar, text, transcript, tags or prompt topics; each operation has its own inputs.

For speech, select a supported voice and use the returned job ID for status and the audio artifact.

Transcripts and tags require a video identifier. Empty results and unsupported languages are shown without invented replacements.

Text to speech API endpoints and pricing

OpenAPI 3.1 JSON

Select an operation above and open API & Docs for parameters and cURL, JavaScript, Python or PHP examples. The web tool uses your signed-in session; external integrations use a Bearer API key.

Method	Endpoint	Cost
POST	Grammar check `/api/v1/grammar/check` Helpful?	1 credit / request≈ $0.001
POST	Text generate `/api/v1/text/generate` Helpful?	2 credit / request≈ $0.002
GET	Video transcript `/api/v1/videos/{video}/transcript` Helpful?	1.5 credit / request≈ $0.0015
GET	Video tags `/api/v1/videos/{video}/tags` Helpful?	0.5 credit / request≈ $0.0005
GET	List AI prompt topics catalog `/api/v1/content/prompts/topics` Helpful?	0.1 credit / request≈ $0.0001
POST	Text to speech synthesis `/api/v1/audio/tts` Helpful?	5 credit / 1,000 characters≈ $0.005
GET	Get audio TTS job status `/api/v1/audio/tts/{job}` Helpful?	0 credit / request
GET	Download audio artifact `/api/v1/audio/tts/{job}/artifact` Helpful?	0 credit / request
DELETE	Cancel audio job and purge state `/api/v1/audio/tts/{job}` Helpful?	0 credit / request
GET	List TTS voices catalog `/api/v1/tts/voices` Helpful?	0.1 credit / request≈ $0.0001

Text to speech API: frequently asked questions

What is the text to speech API?

It converts text into spoken audio. The same group has a YouTube transcript API, a grammar check API and AI text generation, so one TTS API key covers all of them.

What can I send to the grammar check?

Plain text up to 50,000 characters with an optional language code.

How long can the text for text to speech be?

Up to 2,000 characters per request. Billing is per 1,000 characters.

Does every video have a transcript?

No. Transcripts and tags depend on the video and the language. Empty results and unsupported languages are reported as they are, not replaced.

How is it billed?

Per request, and per 1,000 characters for text to speech. Checking a job, downloading the artifact and cancelling are free. See the endpoint table below. New accounts receive 200 credits after verification.

Before integrating

Live and example data

Check the Live or Sandbox label before running. Examples demonstrate the response structure and do not guarantee live service status.

Credits and limits

Pricing depends on the endpoint and billable units. Failed live requests are not replaced with billable examples. Check your account limits before running repeated requests.

View pricing

Handling errors

Keep the request ID for troubleshooting. For 429, respect Retry-After when provided. If a create or delete request loses its connection, check the resource state before retrying.

Related APIs

All APIs

Often used together: YouTube Scraper API · AI Image Generation API · SEO API

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Text to Speech API & YouTube Transcript API

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