Google Text to Speech Service for Twilio

Extends Twilio's text to speech capabilities with Google Cloud Text to Speech.

Twilio and Google provide text-to-speech support for 32 languages each. The following languages are available on Google's Text to Speech api that are not available on Twilio as of December 2019:

• Arabic
• Czech
• Filipino
• Greek
• Hungarian
• Indonesian
• Slovak
• Ukrainian
• Vietnamese

Setup

Prerequisites

1. Install the Google Cloud SDK: brew cask install google-cloud-sdk
2. Install gsutil: https://cloud.google.com/storage/docs/gsutil_install
3. Create a new project: https://console.cloud.google.com/projectcreate
4. Enable the Speech to Text API: https://console.cloud.google.com/flows/enableapi?apiid=texttospeech.googleapis.com
5. Create a service account and download JSON key file: https://console.cloud.google.com/apis/credentials/serviceaccountkey

Create Google Cloud Resources

1. Authenticate gcloud cli tool: gcloud auth login
2. Create a project: gcloud projects create [PROJECT_NAME]
3. Check project was created: gcloud projects describe [PROJECT_ID]
4. Create a cloud storage bucket: gsutil mb -p [PROJECT_NAME] gs://[BUCKET_NAME]
5. Make cloud storage bucket publicly accessible: gsutil defacl set public-read gs://[BUCKET_NAME]

Run Locally

1. Clone the repo: git clone [repo]
2. Go into repo directory: cd gcp-tts
3. Save JSON key file as gcloud-key.json
4. Copy .env.sample to .env and specify GCLOUD_STORAGE_BUCKET and API_KEY
5. Copy app.yaml.sample to app.yaml and specify GCLOUD_STORAGE_BUCKET and API_KEY
6. Install dependencies: npm install
7. Start local server: npm start

Deploy

1. Create an AppEngine app: gcloud app create --project=[PROJECT_NAME]
2. gcloud app deploy --project=[PROJECT_NAME]

Usage:

Sample Requests

Make POST requests to https://[APP_NAME].appspot.com with the following parameters:

{
	"text": "Text to be recorded to speech file.",
	"languageCode": "One of the languages from the list of [Supported Voices and Languages](https://cloud.google.com/text-to-speech/docs/voices). E.g. ar-XA",
	"ssmlGender": "NEUTRAL",
	"name": "One of the voice names from the list of [Supported Voices and Languages](https://cloud.google.com/text-to-speech/docs/voices). E.g. ar-XA-Standard-A",
	"apiKey": "Random string to include in requests. Set in .env and app.yaml files to verify requests."
}

Example request body:

{
	"text": "Nhiệm vụ của Lone Star Legal Aid là bảo vệ và nâng cao các quyền pháp lý dân sự của hàng triệu người dân Texas sống trong nghèo đói trong khu vực dịch vụ 76 quận của mình bằng cách vận động miễn phí, đại diện pháp lý và giáo dục cộng đồng để đảm bảo công bằng.",
	"languageCode": "vi-VN",
	"ssmlGender": "NEUTRAL",
	"name": "vi-VN-Standard-A",
	"apiKey": "atryfyjei3043094"
}

Service Costs

Google Text to Speech

Feature Monthly free tier Paid usage Standard (non-WaveNet) voices 0 to 4 million characters $4.00 USD / 1 million characters WaveNet voices 0 to 1 million characters $16.00 USD / 1 million characters

Google Cloud Storage

Standard Storage (recommended): $0.026 / GB / Month

Google AppEngine

B1 Class Instance in US-West2: $0.6 per hour.