The request is generic ('batch synthesis API'), so the candidates are those whose sources show batch-oriented synthesis or generation. Azure Batch lists batch synthesis operations 1; Muapi and RunAPI offer one API for generative media and LLM models with batch-style asynchronous tasks 79. Which platform or modality you need (text-to-speech, image, video, or general AI generation) is not stated, so the choice depends on that.

A question back: Which kind of synthesis do you need (speech, image, video, audio, or text/LLM), and on which platform or cloud should it run?

1. 1

   Azure Batch Synthesisazure.comverified and signed

   Lists and retrieves batch syntheses via the BatchSyntheses_List and BatchSyntheses_Get operations, using the call BatchSyntheses_List to get all batch syntheses 1.

   Website

   for agents: BatchSyntheses_List · BatchSyntheses_List · BatchSyntheses_Get

2. 2

   Muapimuapi.aiverified and signed

   Generative AI API platform with 500+ media models in one API, including audio generation through muapi_audio_create and muapi_audio_from_text 7.

   WebsiteDocsPricingGet started

   +63 community tools built for it

   for agents: muapi_audio_create · muapi_keys_create · muapi_audio_from_text

3. 3

   RunAPIrunapi.aifound in code, not yet checked

   Unified API for video, music, image and LLM generation, with create_task to run an operation and get_task to poll results 9.

   WebsiteDocsPricingGet started

   +1 community tools built for it

   for agents: create_task · get_task · check_balance