Inworld TTS 1.5.

Inworld TTS 1.5 Overview

Inworld-TTS-1.5 is an advanced text-to-speech (TTS) model that converts written text into natural, expressive, and human-like speech. Designed for low latency and real-time performance, it supports high-quality voice output for applications such as voice assistants, games, interactive experiences, and content creation.

The text input defines spoken content while the exposed voice and audio settings shape delivery.

Inworld TTS 1.5 from Inworld is available through each::labs in the Inworld family. Required fields are text.

voice_id: Inworld voice identifier. model_id: Inworld model identifier.

Use the Inworld TTS 1.5 API when you need this transformation or analysis as a repeatable step in an application or creative pipeline. The sections below distinguish the required material, adjustable controls and checks that matter before delivery.

Capabilities

• The text input defines spoken content while the exposed voice and audio settings shape delivery.
• voice_id: Inworld voice identifier.
• model_id: Inworld model identifier.
• audio_encoding: Audio encoding format.
• Produces a audio result for the next stage of your workflow.

Use Cases for Inworld TTS 1.5

Inworld TTS 1.5 is useful when this specific operation fits between source preparation and delivery. These scenarios show how it can support different parts of a working pipeline.

Creators

Generate narration for a tutorial. Use a representative source or a concise brief, then inspect the result before preparing a larger set of assets.

Design and marketing teams

Prototype a character line. Compare the result with the intended message, composition and destination. Keep reviewable versions of the source and output.

Developers

Create an audio version of a written introduction. Inspect the actual returned value before connecting it to another step, and keep the chosen request settings with the result.

Start with a clear definition of the desired result and use the exposed controls to reach it. Keep any additional generation, editing or application logic in separate steps so that the effect of this operation remains easy to review.

Tips and Tricks

Use clean source material where the request accepts audio or video. For a generative prompt, describe the desired sound, pacing and arrangement clearly. Change one exposed control at a time when comparing a result.

• model_id: Inworld model identifier.
• audio_encoding: Audio encoding format.

• Example direction: “Welcome to the short tutorial. We will review the main steps together.”
• Example direction: “Here is a brief introduction to the new collection.”

Compare one deliberate adjustment at a time. Inspect the part of the result affected by that change, then check the rest of the asset or response for unwanted side effects before reusing the settings.

Technical Specifications

• Result type: audio.
• Required fields: text.
• text: string.
• voice_id: string; options 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, Yichen, Xiaoyin, Xinyi, Jing, Erik, Katrien, Lennart, Lore, Alain, Hélène, Mathieu, Étienne, Johanna, Josef, Gianni, Orietta, Asuka, Satoshi, Hyunwoo, Minji, Seojun, Yoona, Szymon, Wojciech, Heitor, Maitê, Diego, Lupita, Miguel, Rafael, Svetlana, Elena, Dmitry, Nikolai, Riya, Manoj, Yael, Oren, Nour, Omar, 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, Kayla, Nate, Jake, Brian, Amina, Kelsey, Derek, Grant, Evan; default "Alex".
• model_id: string; options inworld-tts-1.5-mini, inworld-tts-1.5-max; default "inworld-tts-1.5-mini".
• audio_encoding: string or null; options MP3, LINEAR16, OGG_OPUS, FLAC, ALAW, MULAW, None; default "MP3".

Values must use the types and accepted options listed in the parameter reference. A displayed default does not remove a required-field requirement. Choose a supported output setting for this entry rather than borrowing a preset from a related model.

Things to Be Aware Of

Listen to the full result and inspect any returned structured data separately. Pronunciation, timing, unwanted sounds and transitions can require manual review even when a request completes successfully.

Optional settings are not necessarily interchangeable with those on another entry in the same family. Use the accepted names, types and values shown for this operation.

Check the returned content against the original input and your application requirements. A successful request means the operation completed; your application still needs to verify that the response is suitable for the next step.

Key Considerations

Check pronunciation, sentence boundaries and the selected output encoding by listening to a short sample.

Public estimate: $5e-06–$1e-05 per character.

Prepare text before starting. Optional settings include voice_id, model_id, audio_encoding. Keep these settings aligned with the intended delivery, especially when a later step expects a particular type or format.

Run a representative request before scaling to a larger collection. Judge the result against the source and the brief, and account for all generated outputs or usage-sensitive options when estimating a batch.

Limitations

• text: minimum characters: 1; maximum characters: 2000.
• voice_id: allowed values: ["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", "Yichen", "Xiaoyin", "Xinyi", "Jing", "Erik", "Katrien", "Lennart", "Lore", "Alain", "Hélène", "Mathieu", "Étienne", "Johanna", "Josef", "Gianni", "Orietta", "Asuka", "Satoshi", "Hyunwoo", "Minji", "Seojun", "Yoona", "Szymon", "Wojciech", "Heitor", "Maitê", "Diego", "Lupita", "Miguel", "Rafael", "Svetlana", "Elena", "Dmitry", "Nikolai", "Riya", "Manoj", "Yael", "Oren", "Nour", "Omar", "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", "Kayla", "Nate", "Jake", "Brian", "Amina", "Kelsey", "Derek", "Grant", "Evan"].

Unsupported parameters do not establish additional capabilities. A generated result can differ from the intended brief, so review detail and consistency before publication.