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Azure Text-to-Speech for Bolna AI voice agents

Azure Text-to-Speech gives your Bolna voice agent Microsoft's neural voices in many languages, covered by Bolna's flat per-minute rate on the neural model.

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At a glance

How Azure Text-to-Speech fits in the stack

Best for

Natural delivery, tone, and response speed on live calls.

Use this layer when

You care about voice quality, expressiveness, or low-latency playback.

Connects to

LLM output upstream and the phone network downstream.

Voice Stack

Text-to-speech is the speaking layer

Text-to-speech is the speaking layer

This provider turns the agent’s response into audio the caller hears. It affects brand perception, caller comfort, and how quickly the next utterance can begin.

TelephonyPhone Network
→
STTListener
→
LLMReasoning
→
TTSVoice
→
ToolsActions

Last updated

What is Azure Text-to-Speech used for in a Bolna voice agent?

Azure Text-to-Speech is Microsoft's neural speech synthesis service, and in Bolna it turns your agent's replies into speech using Azure neural voices. Bolna's provider guide recommends it for multilingual and enterprise agents, since it is strong across many languages.

The Bolna docs describe Azure TTS as supporting over 140 languages, with SSML and custom lexicons for pronouncing technical terms and company names.

How do I set up Azure Text-to-Speech with Bolna?

  1. Optional: connect your own Azure account at platform.bolna.ai/auth/azure.
  2. Open your agent in Agent Studio and go to the Languages tab.
  3. Pick the language you are configuring, then in the Voice section choose AzureTTS as the provider.
  4. Select the neural model and pick a voice. Use the play button to preview it with your welcome message.
  5. If you build the agent through the API, set provider to azuretts and include language inside provider_config. It is required.

For more detail, see the Azure Text-to-Speech setup guide in the Bolna docs.

Which Azure TTS models does Bolna support?

DetailValue
API provider valueazuretts
Modelneural
LanguagesOver 140, per the Bolna docs
language in provider_configRequired
Flat-rate pricingneural is on Bolna's preferred model list
Own accountConnect at platform.bolna.ai/auth/azure

What can you build with Azure Text-to-Speech and Bolna?

An all-Azure voice stack. Pair Azure TTS with Azure speech-to-text and Azure OpenAI to keep transcription, reasoning and voice in the Microsoft ecosystem.

Multilingual support lines. Give each language tab its own Azure voice so callers hear a native-sounding voice in their language.

Recruitment and HR screening. The Bolna docs describe using Azure's pronunciation controls for job roles and company names in interview and screening calls.

Predictable pricing at scale. Because neural is on the preferred list, an agent that also uses preferred transcriber and LLM models stays on Bolna's flat rate. See pricing.

FAQ

Azure Text-to-Speech on Bolna: frequently asked questions

Yes. Choose AzureTTS as the voice provider on the agent's Languages tab. Through the API the provider value is `azuretts`, not `azure`.

Yes. Azure's `neural` model is on Bolna's preferred model list, so it is covered by the flat per-minute rate.

Yes. Connect your own Azure account at platform.bolna.ai/auth/azure and use it with your agents.

Yes. `language` is required inside `provider_config` for `azuretts`. Leaving it out fails with a 400 error, even if the transcriber already has a language.

Related

Other providers in this layer

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Amazon Polly

Amazon Polly gives your Bolna voice agent low-cost text-to-speech with generative, neural and standard engines across a broad range of locales.

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Cartesia

Cartesia gives your Bolna voice agent fast Sonic text-to-speech in 42 languages, including Hindi, with voice cloning and your own API key.

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Custom TTS

Custom TTS lets your Bolna voice agent speak through your own OpenAI-compatible text-to-speech server, such as vLLM-Omni or an open-weight model, with your key.

Browse this layer

Keep exploring the voice stack

Browse

Text-to-Speech

Text-to-speech turns your agent responses into spoken audio. Voice quality shapes how callers perceive your brand. Flat, robotic speech kills trust while natural, expressive voices build it. Bolna integrates with the fastest TTS providers so responses sound human and arrive without awkward pauses.

Browse

Telephony

Telephony providers connect your voice agents to the phone network so they can make and receive real calls. Bolna supports managed integrations with major carriers as well as bring-your-own-carrier via SIP trunking, giving you full control over call routing, number provisioning, and cost.

Browse

Large Language Models

The LLM is the brain of your voice agent. It understands what callers say and decides how to respond. Bolna lets you switch between models like GPT-5.4 mini, Claude and DeepSeek by changing the provider and model in your agent LLM settings, so you can tune for speed, cost or reasoning depth.

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Speech-to-Text

Speech-to-text converts what callers say into text that your LLM can process. Transcription accuracy and latency directly affect how natural a conversation feels. Bolna supports streaming STT providers optimized for telephony audio, including specialized models for Indian languages.

Browse

Tools & Workflows

Tools let your voice agents take action during a call, not just talk. Book a calendar slot, look up an order through your own API, push a lead into your CRM, or trigger a multi-step automation in Zapier. These integrations turn voice agents from answering machines into workflow engines.

See where Azure Text-to-Speech fits in your production workflow

Use the demo to walk through provider selection, stack tradeoffs, and the exact workflow you want Bolna to automate.

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