--- title: Inworld Realtime TTS-2 | Runware Docs url: https://runware.ai/docs/models/inworld-tts-2 description: Conversational text-to-speech with realtime voice direction and audio-aware delivery --- # Inworld Realtime TTS-2 Inworld Realtime TTS-2 is a conversational text-to-speech model built for realtime voice interaction rather than static narration. It supports free-form voice direction, carries tone and pacing forward from prior audio in a session, preserves one voice identity across 100+ languages, and is designed for expressive, low-latency speech in assistants, characters, support agents, and interactive products. - **ID**: `inworld:tts@2` - **Status**: live - **Creator**: Inworld AI - **Release Date**: May 5, 2026 - **Capabilities**: Text to Audio, Checkpoint ## Pricing - **1000 input characters**: `$0.035` ## Compatibility & Validation When `speech.language` is `en`, `speech.voice` is limited to `Loretta`, `Darlene`, `Marlene`, `Hank`, `Evelyn`, `Celeste`, `Pippa`, `Tessa`, `Liam`, `Callum`, `Hamish`, `Abby`, `Graham`, `Rupert`, `Mortimer`, `Snik`, `Anjali`, `Saanvi`, `Arjun`, `Claire`, `Oliver`, `Simon`, `Elliot`, `James`, `Serena`, `Gareth`, `Vinny`, `Lauren`, `Jessica`, `Ethan`, `Tyler`, `Jason`, `Chloe`, `Veronica`, `Victoria`, `Miranda`, `Sebastian`, `Victor`, `Malcolm`, `Nate`, `Brian`, `Amina`, `Kelsey`, `Derek`, `Evan`, `Kayla`, `Jake`, `Grant`, `Tristan`, `Nadia`, `Selene`, `Marcus`, `Riley`, `Damon`, `Cedric`, `Mia`, `Naomi`, `Jonah`, `Levi`, `Avery`, `Brandon`, `Conrad`, `Bianca`, `Lucian`, `Trevor`, `Alex`, `Ashley`, `Craig`, `Deborah`, `Dennis`, `Edward`, `Elizabeth`, `Hades`, `Julia`, `Pixie`, `Mark`, `Olivia`, `Priya`, `Ronald`, `Sarah`, `Shaun`, `Theodore`, `Timothy`, `Wendy`, `Dominus`, `Hana`, `Clive`, `Carter`, `Blake`, `Luna`, `Reed`, `Duncan`, `Felix`, `Eleanor`, `Sophie`. --- When `speech.language` is `ja`, `speech.voice` is limited to `Asuka`, `Satoshi`. --- When `speech.language` is `zh`, `speech.voice` is limited to `Yichen`, `Xiaoyin`, `Xinyi`, `Jing`. --- When `speech.language` is `ko`, `speech.voice` is limited to `Hyunwoo`, `Minji`, `Seojun`, `Yoona`. --- When `speech.language` is `ru`, `speech.voice` is limited to `Svetlana`, `Elena`, `Dmitry`, `Nikolai`. --- When `speech.language` is `it`, `speech.voice` is limited to `Gianni`, `Orietta`. --- When `speech.language` is `es`, `speech.voice` is limited to `Diego`, `Lupita`, `Miguel`, `Rafael`. --- When `speech.language` is `de`, `speech.voice` is limited to `Johanna`, `Josef`. --- When `speech.language` is `fr`, `speech.voice` is limited to `Alain`, `Hélène`, `Mathieu`, `Étienne`. --- When `speech.language` is `ar`, `speech.voice` is limited to `Nour`, `Omar`. --- When `speech.language` is `pl`, `speech.voice` is limited to `Szymon`, `Wojciech`. --- When `speech.language` is `nl`, `speech.voice` is limited to `Erik`, `Katrien`, `Lennart`, `Lore`. --- When `speech.language` is `hi`, `speech.voice` is limited to `Riya`, `Manoj`. --- When `speech.language` is `he`, `speech.voice` is limited to `Yael`, `Oren`. ## Request Parameters **API Options** Platform-level options for task execution and delivery. ### [taskType](https://runware.ai/docs/models/inworld-tts-2#request-tasktype) - **Type**: `string` - **Required**: true - **Value**: `audioInference` Identifier for the type of task being performed ### [taskUUID](https://runware.ai/docs/models/inworld-tts-2#request-taskuuid) - **Type**: `string` - **Required**: true - **Format**: `UUID v4` UUID v4 identifier for tracking tasks and matching async responses. Must be unique per task. ### [outputType](https://runware.ai/docs/models/inworld-tts-2#request-outputtype) - **Type**: `string` - **Default**: `URL` Audio output type. **Allowed values**: `URL` `base64Data` `dataURI` ### [outputFormat](https://runware.ai/docs/models/inworld-tts-2#request-outputformat) - **Type**: `string` - **Default**: `MP3` Specifies the file format of the generated output. The available values depend on the task type and the specific model's capabilities. - \`MP3\`: Compressed audio, smaller file size. - \`WAV\`: Uncompressed, high-quality audio. - \`FLAC\`: Lossless compression. - \`OGG\`: Open-source compressed audio format (Vorbis codec). **Allowed values**: `MP3` `WAV` `FLAC` `OGG` ### [audioSettings](https://runware.ai/docs/models/inworld-tts-2#request-audiosettings) - **Path**: `audioSettings.bitrate` - **Type**: `object (3 properties)` Audio encoding settings for controlling the bitrate, number of channels, and sample rate of the generated audio. Only applicable for lossy output formats (`MP3` and `OGG`). When using lossless formats (`WAV` or `FLAC`), this parameter must not be provided. The available sample rates and valid bitrate ranges depend on the output format. For `OGG`, bitrate limits also vary by the number of channels. **MP3 bitrate limits**: Bitrate limits for MP3 are the same regardless of mono or stereo. | Sample Rate | Min Bitrate | Max Bitrate | | --- | --- | --- | | 8,000 Hz | 8 kbps | 64 kbps | | 11,025 Hz | 8 kbps | 64 kbps | | 12,000 Hz | 8 kbps | 64 kbps | | 16,000 Hz | 8 kbps | 160 kbps | | 22,050 Hz | 8 kbps | 160 kbps | | 24,000 Hz | 8 kbps | 160 kbps | | 32,000 Hz | 32 kbps | 320 kbps | | 44,100 Hz | 32 kbps | 320 kbps | | 48,000 Hz | 32 kbps | 320 kbps | **OGG bitrate limits — Mono (1 channel)**: | Sample Rate | Min Bitrate | Max Bitrate | | --- | --- | --- | | 8,000 Hz | 8 kbps | 40 kbps | | 12,000 Hz | 16 kbps | 48 kbps | | 16,000 Hz | 16 kbps | 96 kbps | | 24,000 Hz | 16 kbps | 80 kbps | | 48,000 Hz | 32 kbps | 224 kbps | **OGG bitrate limits — Stereo (2 channels)**: | Sample Rate | Min Bitrate | Max Bitrate | | --- | --- | --- | | 8,000 Hz | 16 kbps | 80 kbps | | 12,000 Hz | 16 kbps | 96 kbps | | 16,000 Hz | 24 kbps | 192 kbps | | 24,000 Hz | 32 kbps | 160 kbps | | 48,000 Hz | 48 kbps | 256 kbps | > [!NOTE] > **Lossless formats**: When `outputFormat` is set to `WAV` or `FLAC`, the `audioSettings` parameter is not available since these formats produce uncompressed or lossless audio with no configurable encoding settings. #### [bitrate](https://runware.ai/docs/models/inworld-tts-2#request-audiosettings-bitrate) - **Path**: `audioSettings.bitrate` - **Type**: `integer` - **Min**: `8` Audio bitrate in kbps. #### [channels](https://runware.ai/docs/models/inworld-tts-2#request-audiosettings-channels) - **Path**: `audioSettings.channels` - **Type**: `integer` - **Default**: `2` Number of audio channels. 1 for mono, 2 for stereo. **Allowed values**: `1` `2` #### [sampleRate](https://runware.ai/docs/models/inworld-tts-2#request-audiosettings-samplerate) - **Path**: `audioSettings.sampleRate` - **Type**: `integer` Audio sample rate in Hz. ### [webhookURL](https://runware.ai/docs/models/inworld-tts-2#request-webhookurl) - **Type**: `string` - **Format**: `uri` Specifies a webhook URL where JSON responses will be sent via HTTP POST when generation tasks complete. For batch requests with multiple results, each completed item triggers a separate webhook call as it becomes available. **Learn more** (1 resource): - [Webhooks](https://runware.ai/docs/platform/webhooks) (platform) ### [deliveryMethod](https://runware.ai/docs/models/inworld-tts-2#request-deliverymethod) - **Type**: `string` - **Default**: `sync` Determines how the API delivers task results. **Allowed values**: - `sync` Returns complete results directly in the API response. - `async` Returns an immediate acknowledgment with the task UUID. Poll for results using getResponse. **Learn more** (1 resource): - [Task Polling](https://runware.ai/docs/platform/task-polling) (platform) ### [uploadEndpoint](https://runware.ai/docs/models/inworld-tts-2#request-uploadendpoint) - **Type**: `string` - **Format**: `uri` Specifies a URL where the generated content will be automatically uploaded using the HTTP PUT method. The raw binary data of the media file is sent directly as the request body. For secure uploads to cloud storage, use presigned URLs that include temporary authentication credentials. **Common use cases:** - **Cloud storage**: Upload directly to S3 buckets, Google Cloud Storage, or Azure Blob Storage using presigned URLs. - **CDN integration**: Upload to content delivery networks for immediate distribution. ```text // S3 presigned URL for secure upload https://your-bucket.s3.amazonaws.com/generated/content.mp4?X-Amz-Signature=abc123&X-Amz-Expires=3600 // Google Cloud Storage presigned URL https://storage.googleapis.com/your-bucket/content.jpg?X-Goog-Signature=xyz789 // Custom storage endpoint https://storage.example.com/uploads/generated-image.jpg ``` The content data will be sent as the request body to the specified URL when generation is complete. ### [ttl](https://runware.ai/docs/models/inworld-tts-2#request-ttl) - **Type**: `integer` - **Min**: `60` Time-to-live (TTL) in seconds for generated content. Only applies when `outputType` is `URL`. ### [includeCost](https://runware.ai/docs/models/inworld-tts-2#request-includecost) - **Type**: `boolean` Include task cost in the response. ### [numberResults](https://runware.ai/docs/models/inworld-tts-2#request-numberresults) - **Type**: `integer` - **Min**: `1` - **Max**: `4` - **Default**: `1` Number of results to generate. Each result uses a different seed, producing variations of the same parameters. **Core Parameters** Primary parameters that define the task output. ### [model](https://runware.ai/docs/models/inworld-tts-2#request-model) - **Type**: `string` - **Required**: true - **Value**: `inworld:tts@2` Identifier of the model to use for generation. **Learn more** (3 resources): - [Text To Image: Model Selection](https://runware.ai/docs/learn/text-to-image#model-selection) (learn) - [Image Inpainting: Model Specialized Inpainting Models](https://runware.ai/docs/learn/image-inpainting#model-specialized-inpainting-models) (learn) - [Image Outpainting: Other Critical Parameters](https://runware.ai/docs/learn/image-outpainting#other-critical-parameters) (learn) ### [speech](https://runware.ai/docs/models/inworld-tts-2#request-speech) - **Path**: `speech.text` - **Type**: `object (4 properties)` - **Required**: true Settings for speech generation. #### [text](https://runware.ai/docs/models/inworld-tts-2#request-speech-text) - **Path**: `speech.text` - **Type**: `string` - **Required**: true - **Min**: `2` - **Max**: `2000` Text to convert to speech. #### [voice](https://runware.ai/docs/models/inworld-tts-2#request-speech-voice) - **Path**: `speech.voice` - **Type**: `string` - **Required**: true Voice identifier to use for speech generation. **Allowed values**: `Loretta` `Darlene` `Marlene` `Hank` `Evelyn` `Celeste` `Pippa` `Tessa` `Liam` `Callum` `Hamish` `Abby` `Graham` `Rupert` `Mortimer` `Snik` `Anjali` `Saanvi` `Arjun` `Claire` `Oliver` `Simon` `Elliot` `James` `Serena` `Gareth` `Vinny` `Lauren` `Jessica` `Ethan` `Tyler` `Jason` `Chloe` `Veronica` `Victoria` `Miranda` `Sebastian` `Victor` `Malcolm` `Nate` `Brian` `Amina` `Kelsey` `Derek` `Evan` `Kayla` `Jake` `Grant` `Tristan` `Nadia` `Selene` `Marcus` `Riley` `Damon` `Cedric` `Mia` `Naomi` `Jonah` `Levi` `Avery` `Brandon` `Conrad` `Bianca` `Lucian` `Trevor` `Alex` `Ashley` `Craig` `Deborah` `Dennis` `Edward` `Elizabeth` `Hades` `Julia` `Pixie` `Mark` `Olivia` `Priya` `Ronald` `Sarah` `Shaun` `Theodore` `Timothy` `Wendy` `Dominus` `Hana` `Clive` `Carter` `Blake` `Luna` `Reed` `Duncan` `Felix` `Eleanor` `Sophie` `Asuka` `Satoshi` `Yichen` `Xiaoyin` `Xinyi` `Jing` `Hyunwoo` `Minji` `Seojun` `Yoona` `Svetlana` `Elena` `Dmitry` `Nikolai` `Gianni` `Orietta` `Diego` `Lupita` `Miguel` `Rafael` `Johanna` `Josef` `Alain` `Hélène` `Mathieu` `Étienne` `Nour` `Omar` `Szymon` `Wojciech` `Erik` `Katrien` `Lennart` `Lore` `Riya` `Manoj` `Yael` `Oren` #### [language](https://runware.ai/docs/models/inworld-tts-2#request-speech-language) - **Path**: `speech.language` - **Type**: `string` - **Min**: `1` Language code for speech generation. **Allowed values**: `en` `ja` `zh` `ko` `ru` `it` `es` `de` `fr` `ar` `pl` `nl` `hi` `he` #### [speed](https://runware.ai/docs/models/inworld-tts-2#request-speech-speed) - **Path**: `speech.speed` - **Type**: `float` - **Min**: `0.5` - **Max**: `1.5` - **Step**: `0.1` - **Default**: `1` Playback speed of the generated speech. **Settings** Technical parameters to fine-tune the inference process. These must be nested inside the \`settings\` object. ### [textNormalization](https://runware.ai/docs/models/inworld-tts-2#request-settings-textnormalization) - **Path**: `settings.textNormalization` - **Type**: `boolean` Expands numbers, dates, abbreviations before speech generation. ## Response Parameters ### [taskType](https://runware.ai/docs/models/inworld-tts-2#response-tasktype) - **Type**: `string` - **Required**: true - **Value**: `audioInference` Identifier for the type of task this response belongs to. ### [taskUUID](https://runware.ai/docs/models/inworld-tts-2#response-taskuuid) - **Type**: `string` - **Required**: true - **Format**: `UUID v4` UUID v4 identifier echoed from the original request, used to match async responses to their tasks. ### [audioUUID](https://runware.ai/docs/models/inworld-tts-2#response-audiouuid) - **Type**: `string` - **Required**: true - **Format**: `UUID v4` UUID of the output audio. ### [audioURL](https://runware.ai/docs/models/inworld-tts-2#response-audiourl) - **Type**: `string` - **Format**: `uri` URL of the output audio. ### [audioBase64Data](https://runware.ai/docs/models/inworld-tts-2#response-audiobase64data) - **Type**: `string` Base64-encoded audio data. ### [audioDataURI](https://runware.ai/docs/models/inworld-tts-2#response-audiodatauri) - **Type**: `string` - **Format**: `uri` Data URI of the output audio. ### [seed](https://runware.ai/docs/models/inworld-tts-2#response-seed) - **Type**: `integer` The seed used for generation. If none was provided, shows the randomly generated seed. ### [cost](https://runware.ai/docs/models/inworld-tts-2#response-cost) - **Type**: `float` Task cost in USD. Present when `includeCost` is set to `true` in the request. ## Examples ### Desert Relay Station Dispatch (Text to Audio) --- ### Floating Archive Welcome Message (Text to Audio) --- ### Orbital Docking Concierge Briefing (Text to Audio) --- ### Subterranean Transit Delay Announcement (Text to Audio) --- ### Harbor Emergency Siren Bulletin (Text to Audio)