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Baeldung Pro comes with both absolutely No-Ads as well as finally with Dark Mode, for a clean learning experience:

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Once the early-adopter seats are all used, the price will go up and stay at $33/year.

Partner – Microsoft – NPI EA (cat = Baeldung)
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Azure Container Apps is a fully managed serverless container service that enables you to build and deploy modern, cloud-native Java applications and microservices at scale. It offers a simplified developer experience while providing the flexibility and portability of containers.

Of course, Azure Container Apps has really solid support for our ecosystem, from a number of build options, managed Java components, native metrics, dynamic logger, and quite a bit more.

To learn more about Java features on Azure Container Apps, visit the documentation page.

You can also ask questions and leave feedback on the Azure Container Apps GitHub page.

Partner – Microsoft – NPI EA (cat= Spring Boot)
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Azure Container Apps is a fully managed serverless container service that enables you to build and deploy modern, cloud-native Java applications and microservices at scale. It offers a simplified developer experience while providing the flexibility and portability of containers.

Of course, Azure Container Apps has really solid support for our ecosystem, from a number of build options, managed Java components, native metrics, dynamic logger, and quite a bit more.

To learn more about Java features on Azure Container Apps, you can get started over on the documentation page.

And, you can also ask questions and leave feedback on the Azure Container Apps GitHub page.

Partner – Orkes – NPI EA (cat=Spring)
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Modern software architecture is often broken. Slow delivery leads to missed opportunities, innovation is stalled due to architectural complexities, and engineering resources are exceedingly expensive.

Orkes is the leading workflow orchestration platform built to enable teams to transform the way they develop, connect, and deploy applications, microservices, AI agents, and more.

With Orkes Conductor managed through Orkes Cloud, developers can focus on building mission critical applications without worrying about infrastructure maintenance to meet goals and, simply put, taking new products live faster and reducing total cost of ownership.

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Partner – Orkes – NPI EA (tag=Microservices)
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Modern software architecture is often broken. Slow delivery leads to missed opportunities, innovation is stalled due to architectural complexities, and engineering resources are exceedingly expensive.

Orkes is the leading workflow orchestration platform built to enable teams to transform the way they develop, connect, and deploy applications, microservices, AI agents, and more.

With Orkes Conductor managed through Orkes Cloud, developers can focus on building mission critical applications without worrying about infrastructure maintenance to meet goals and, simply put, taking new products live faster and reducing total cost of ownership.

Try a 14-Day Free Trial of Orkes Conductor today.

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Since its introduction in Java 8, the Stream API has become a staple of Java development. The basic operations like iterating, filtering, mapping sequences of elements are deceptively simple to use.

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Explore Spring Boot 3 and Spring 6 in-depth through building a full REST API with the framework:

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I built the security material as two full courses - Core and OAuth, to get practical with these more complex scenarios. We explore when and how to use each feature and code through it on the backing project.

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Spring Data JPA is a great way to handle the complexity of JPA with the powerful simplicity of Spring Boot.

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End-to-end testing is a very useful method to make sure that your application works as intended. This highlights issues in the overall functionality of the software, that the unit and integration test stages may miss.

Playwright is an easy-to-use, but powerful tool that automates end-to-end testing, and supports all modern browsers and platforms.

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Course – Spring Sale 2025 – NPI (cat=Baeldung)
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Yes, we're now running our Spring Sale. All Courses are 25% off until 26th May, 2025:

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1. Overview

Businesses often need to extract meaningful data from various types of audio content, such as transcribing customer support calls for sentiment analysis, generating subtitles for videos, or generating minutes from meetings. However, manually transcribing audio files is a time-consuming and expensive process.

To automate this process, OpenAI offers powerful speech-to-text models capable of accurately transcribing audio files in multiple languages.

In this tutorial, we’ll explore how to transcribe audio files with OpenAI’s speech-to-text models using Spring AI.

To follow along with this tutorial, we’ll need an OpenAI API key.

2. Setting up the Project

Before we can start implementing our audio transcriber, we’ll need to include the necessary dependency and configure our application correctly.

2.1. Dependencies

Let’s start by adding Spring AI’s OpenAI starter dependency to our project’s pom.xml file:

<dependency>
    <groupId>org.springframework.ai</groupId>
    <artifactId>spring-ai-starter-model-openai</artifactId>
    <version>1.0.0-M7</version>
</dependency>

Since the current version, 1.0.0-M7, is a milestone release, we’ll also need to add the Spring Milestones repository to our pom.xml:

<repositories>
    <repository>
        <id>spring-milestones</id>
        <name>Spring Milestones</name>
        <url>https://repo.spring.io/milestone</url>
        <snapshots>
            <enabled>false</enabled>
        </snapshots>
    </repository>
</repositories>

This repository is where milestone versions are published, as opposed to the standard Maven Central repository.

2.2. Configuring OpenAI Properties

Next, let’s configure the OpenAI API key and speech-to-text model in our application.yaml file:

spring:
  ai:
    openai:
      api-key: ${OPENAI_API_KEY}
      audio:
        transcription:
          options:
            model: whisper-1
            language: en

We use the ${} property placeholder to load the value of our API key from an environment variable.

Here, we specify OpenAI’s Whisper model via its model-id of whisper-1. It’s important to note that OpenAI offers more advanced and higher-quality speech-to-text models like gpt-4o-transcribe and gpt-4o-mini-transcribe. However, they’re not supported by the current version of Spring AI.

Additionally, we specify en as the language of our audio files. Alternatively, we can specify a different input language in ISO-639-1 format according to requirements. If not specified, the specified model will attempt to detect the language spoken in the audio automatically.

On configuring the above properties, Spring AI automatically creates a bean of type OpenAiAudioTranscriptionModel, allowing us to interact with the specified model.

3. Building Our Audio Transcriber

With our configurations in place, let’s create an AudioTranscriber service class. We’ll inject the OpenAiAudioTranscriptionModel bean that Spring AI automatically creates for us.

But first, let’s define two simple records to represent the request and response payloads:

record TranscriptionRequest(MultipartFile audioFile, @Nullable String context) {}

record TranscriptionResponse(String transcription) {}

The TranscriptionRequest contains the audioFile to be transcribed and an optional context to help the model with the transcription process. It’s important to note that OpenAI currently supports audio files in mp3, mp4, mpeg, mpga, m4a, wav, and webm formats.

Similarly, the TranscriptionResponse simply holds the generated transcription.

Now, let’s implement the intended functionality:

TranscriptionResponse transcribe(TranscriptionRequest transcriptionRequest) {
    AudioTranscriptionPrompt prompt = new AudioTranscriptionPrompt(
      transcriptionRequest.audioFile().getResource(),
      OpenAiAudioTranscriptionOptions
        .builder()
        .prompt(transcriptionRequest.context())
        .build()
    );
    AudioTranscriptionResponse response = openAiAudioTranscriptionModel.call(prompt);
    return new TranscriptionResponse(response.getResult().getOutput());
}

Here, we add a new transcribe() method to our AudioTranscriber class.

We create an AudioTranscriptionPrompt object using the audioFile resource and the optional context prompt. Then, we use it to invoke the call() method of the autowired OpenAiAudioTranscriptionModel bean.

Finally, we extract the transcribed text from the response and return it wrapped in our TranscriptionResponse record.

Currently, for the speech-to-text models, the audio file size is limited to 25 MB. However, by default, Spring Boot limits the size of uploaded files to 1 MB. Let’s increase this limit in our application.yaml file:

spring:
  servlet:
    multipart:
      max-file-size: 25MB
      max-request-size: 25MB

We set the maximum file size and request size to 25MB, which should be sufficient for most audio transcription requests.

4. Testing Our Audio Transcriber

Now that we’ve implemented our service layer, let’s expose a REST API on top of it:

@PostMapping("/transcribe")
ResponseEntity<TranscriptionResponse> transcribe(
  @RequestParam("audioFile") MultipartFile audioFile,
  @RequestParam("context") String context
) {
    TranscriptionRequest transcriptionRequest = new TranscriptionRequest(audioFile, context);
    TranscriptionResponse response = audioTranscriber.transcribe(transcriptionRequest);
    return ResponseEntity.ok(response);
}

Next, let’s use the HTTPie CLI to invoke the above API endpoint:

http -f POST :8080/transcribe [email protected] context="Short description about Baeldung"

Here, we invoke our /transcribe API and send the audioFile along with its context. For our demonstration, we’ve prepared an audio file that provides a short description of Baeldung. This file can be found in the src/test/resources/audio folder of the codebase.

Let’s see what we get as a response:

{
    "transcription": "Baeldung is a top-notch educational platform that specializes in Java, Spring, and related technologies. It offers a wealth of tutorials, articles, and courses that help developers master programming concepts. Known for its clear examples and practical guides, Baeldung is a go-to resource for developers looking to level up their skills."
}

As we can see, the API returns the correct transcription of the provided audio file.

Notice how providing the context prompt helps the model correctly transcribe the Baeldung name. Without this context, the Whisper model transcribes the word as Baildung.

5. Conclusion

In this article, we’ve explored transcribing audio files with OpenAI in Spring AI.

We walked through the necessary configuration and implemented an audio transcriber using OpenAI’s Whisper speech-to-text model. We also tested our application and saw how providing a context prompt improves the accuracy of the generated transcription, especially for domain-specific names.

As always, all the code examples used in this article are available over on GitHub.

Baeldung Pro – NPI EA (cat = Baeldung)
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Baeldung Pro comes with both absolutely No-Ads as well as finally with Dark Mode, for a clean learning experience:

>> Explore a clean Baeldung

Once the early-adopter seats are all used, the price will go up and stay at $33/year.

Partner – Microsoft – NPI EA (cat = Spring Boot)
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Azure Container Apps is a fully managed serverless container service that enables you to build and deploy modern, cloud-native Java applications and microservices at scale. It offers a simplified developer experience while providing the flexibility and portability of containers.

Of course, Azure Container Apps has really solid support for our ecosystem, from a number of build options, managed Java components, native metrics, dynamic logger, and quite a bit more.

To learn more about Java features on Azure Container Apps, visit the documentation page.

You can also ask questions and leave feedback on the Azure Container Apps GitHub page.

Partner – Orkes – NPI EA (cat = Spring)
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Modern software architecture is often broken. Slow delivery leads to missed opportunities, innovation is stalled due to architectural complexities, and engineering resources are exceedingly expensive.

Orkes is the leading workflow orchestration platform built to enable teams to transform the way they develop, connect, and deploy applications, microservices, AI agents, and more.

With Orkes Conductor managed through Orkes Cloud, developers can focus on building mission critical applications without worrying about infrastructure maintenance to meet goals and, simply put, taking new products live faster and reducing total cost of ownership.

Try a 14-Day Free Trial of Orkes Conductor today.

Partner – Orkes – NPI EA (tag = Microservices)
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Modern software architecture is often broken. Slow delivery leads to missed opportunities, innovation is stalled due to architectural complexities, and engineering resources are exceedingly expensive.

Orkes is the leading workflow orchestration platform built to enable teams to transform the way they develop, connect, and deploy applications, microservices, AI agents, and more.

With Orkes Conductor managed through Orkes Cloud, developers can focus on building mission critical applications without worrying about infrastructure maintenance to meet goals and, simply put, taking new products live faster and reducing total cost of ownership.

Try a 14-Day Free Trial of Orkes Conductor today.

eBook – HTTP Client – NPI EA (cat=HTTP Client-Side)
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The Apache HTTP Client is a very robust library, suitable for both simple and advanced use cases when testing HTTP endpoints. Check out our guide covering basic request and response handling, as well as security, cookies, timeouts, and more:

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eBook – Java Concurrency – NPI EA (cat=Java Concurrency)
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Handling concurrency in an application can be a tricky process with many potential pitfalls. A solid grasp of the fundamentals will go a long way to help minimize these issues.

Get started with understanding multi-threaded applications with our Java Concurrency guide:

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eBook – Java Streams – NPI EA (cat=Java Streams)
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Since its introduction in Java 8, the Stream API has become a staple of Java development. The basic operations like iterating, filtering, mapping sequences of elements are deceptively simple to use.

But these can also be overused and fall into some common pitfalls.

To get a better understanding on how Streams work and how to combine them with other language features, check out our guide to Java Streams:

>> Join Pro and download the eBook

eBook – Persistence – NPI EA (cat=Persistence)
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Working on getting your persistence layer right with Spring?

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Course – LS – NPI EA (cat=REST)

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Get started with Spring Boot and with core Spring, through the Learn Spring course:

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Partner – Microsoft – NPI (cat=Spring)
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Azure Container Apps is a fully managed serverless container service that enables you to build and deploy modern, cloud-native Java applications and microservices at scale. It offers a simplified developer experience while providing the flexibility and portability of containers.

Of course, Azure Container Apps has really solid support for our ecosystem, from a number of build options, managed Java components, native metrics, dynamic logger, and quite a bit more.

To learn more about Java features on Azure Container Apps, visit the documentation page.

You can also ask questions and leave feedback on the Azure Container Apps GitHub page.

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