
Our last blog post discussed accessing project settings for a CustomGPT.ai chatbot using JavaScript. Now, we’ll explore updating project settings with the Kotlin programming language. This blog post will demonstrate how Kotlin facilitates sending HTTP requests and executing various operations through the CustomGPT.ai API, illustrating how CustomGPT.ai works in practice across features like the enterprise RAG API. Through practical programming examples, we’ll showcase the seamless integration of CustomGPT.ai with Kotlin, offering enhanced chatbot functionalities. Let’s get started!
Introduction to Kotlin and its Support for RAG API Integration
Kotlin, introduced by JetBrains in 2011, has rapidly gained popularity as a modern and versatile programming language for building robust applications across various platforms. Known for its concise syntax, strong type inference, and interoperability with Java, Kotlin offers developers a seamless and expressive coding experience.

Regarding integrating APIs from external sources, Kotlin excels due to its extensive support for networking and HTTP libraries. Developers can easily send HTTP requests, handle responses, and parse data using Kotlin’s native libraries or popular third-party frameworks like Retrofit and OkHttp. This flexibility makes Kotlin an excellent choice for integrating external APIs into Kotlin-based applications.
CustomGPT.ai and its comprehensive support for integration with different programming Languages
CustomGPT.ai provides comprehensive support for Kotlin integration, offering developers a range of pre-built code snippets and examples for various functionalities. These include sending requests to create, update, or delete projects, managing conversations, retrieving project settings, and more. With CustomGPT.ai’s Kotlin support, developers can seamlessly incorporate advanced chatbot capabilities into their Kotlin applications, enhancing user experiences and productivity.
Here are some key points highlighting Kotlin’s support for RAG API integrations and CustomGPT.ai’s compatibility with Kotlin:
- HTTP Libraries: Kotlin supports various HTTP libraries like OkHttp and Retrofit, allowing developers to interact with external APIs efficiently.
- Networking Capabilities: Kotlin’s networking capabilities enable seamless communication with external servers, making it easy to send and receive data over the Internet.
- CustomGPT.ai Code Snippets: CustomGPT.ai provides developers with pre-built code snippets and examples tailored for Kotlin, facilitating the integration of custom chatbots into Kotlin applications.
- RAG API Documentation: CustomGPT.ai offers comprehensive RAG API documentation with detailed instructions and examples for integrating chatbots with Kotlin applications.
- Flexibility: Kotlin’s flexibility and interoperability with Java simplify the process of integrating CustomGPT.ai’s AI capabilities into existing Kotlin codebases.
- Community Support: Kotlin boasts a vibrant and active community of developers who contribute libraries, frameworks, and resources to support RAG API integrations and application development.
Overall, Kotlin’s robust features and CustomGPT.ai’s comprehensive support make them a powerful combination for building intelligent and feature-rich applications with seamless RAG API integrations.
Integrating CustomGPT.ai with Kotlin: A Practical Example
In this practical example, we will demonstrate how to retrieve the agent settings for a specific project using Kotlin. We’ll utilize the POST endpoint and Code snippet provided in the CustomGPT.ai RAG API documentation, which allows us to fetch the configuration and settings associated with the project.

In this code snippet:
- We first create an instance of the OkHttpClient class, which is a popular HTTP client for Kotlin.
- We then build a POST request using the Request.Builder() class, specifying the URL endpoint provided by CustomGPT.ai RAG API documentation.
- Additionally, we add the necessary headers, including the accept header to indicate that we expect a JSON response.
- Finally, we execute the request using the client.newCall(request).execute(), which sends the HTTP request to the CustomGPT.ai server and returns a response. This response contains the project settings data, which we can then handle and process as needed within our Kotlin application.
Test and Run the Code in the CustomGPT.ai Browser
To test and run the code in the CustomGPT.ai browser, follow these steps:
- Sign Up for CustomGPT.ai: If you haven’t already, sign up for an account on the CustomGPT.ai website.
- Retrieve RAG API Key: After signing in, navigate to your profile and Click on API> generate an API key. Copy the generated RAG API key as we’ll need it to authenticate our requests.
- Provide the RAG API Key: Paste the RAG API key in the authorization box as shown below.

- Replace Parameters: In the code snippet provided earlier, replace the “projectId” parameter in the URL with the actual project ID you want to retrieve settings for.

- Now provide the parameters you want to update in your CustomGPT.ai Chatbot Project including chatbot avatar, background picture, and parameters on how your chatbot will interact when a user asks a question.

- Now update how your chatbot will behave by providing a customer persona. Also, provide instructions on the source label and set default messages according to your needs.
- You can also update the citation settings and ending message for a conversation within a chatbot.
- Now define the chatbot model you want to set other parameters also like branding and selling.

- Now run the code by clicking on Try It. And see the response.

- The response “200” shows that the project’ setting with given parameters is updated.
Similarly, you can also perform various other operations using Kotlin Code snippets from CustomGPT.ai RAG API documentation.
Conclusion
With Kotlin’s support for RAG API integrations and CustomGPT.ai’s comprehensive RAG API documentation, developers can leverage pre-built code snippets and practical examples, in the integration process and unlock the full potential of CustomGPT.ai’s features. With Kotlin’s concise syntax and CustomGPT.ai’s powerful AI technology, developers can create intelligent applications that deliver personalized experiences to users, driving engagement and efficiency.
Frequently Asked Questions
Can a Kotlin-backed website use the RAG API without forcing visitors to log in to ChatGPT?
Yes. The API uses key-based authentication, so a Kotlin backend can call the OpenAI-compatible /v1/chat/completions endpoint and return answers inside your own site or app. That lets you keep the chat experience in your interface instead of sending users to a separate tool. Bill French described the UX impact this way: u0022They’ve officially cracked the sub-second barrier, a breakthrough that fundamentally changes the user experience from merely ‘interactive’ to ‘instantaneous’.u0022
Can I add more documents to the knowledge base, or does a Kotlin RAG integration use the model directly?
You can keep adding knowledge sources. The system is RAG-powered and supports multi-source ingestion from websites, documents, audio, video, and URLs, with formats such as PDF, DOCX, TXT, CSV, HTML, XML, JSON, audio, and video files up to 100MB each. That means a Kotlin integration can rely on indexed source material instead of a static prompt alone. Stephanie Warlick summed up the knowledge-ingestion use case this way: u0022Check out CustomGPT.ai where you can dump all your knowledge to automate proposals, customer inquiries and the knowledge base that exists in your head so your team can execute without you.u0022
Do I need a Kotlin SDK, or can I call the RAG API with OkHttp or Retrofit?
You do not need a dedicated Kotlin SDK to get started. Kotlin can call the REST API with standard HTTP libraries such as OkHttp or Retrofit, both of which are explicitly highlighted for Kotlin integrations. The published SDK list includes Java but not a dedicated Kotlin SDK, so using normal Kotlin or Java HTTP clients is the straightforward approach.
Can I update chatbot settings programmatically from a Kotlin backend service?
Yes. The Kotlin integration examples specifically cover updating project settings through HTTP requests. The same API support also includes creating, updating, and deleting projects, plus managing conversations, so a server-side Kotlin service can automate settings changes instead of relying only on manual dashboard work. Barry Barresi described a related custom build outcome as: u0022Powered by my custom-built Theory of Change AIM GPT agent on the CustomGPT.ai platform. Rapidly Develop a Credible Theory of Change with AI-Augmented Collaboration.u0022
Is Kotlin a good choice for Android or JVM apps that use a RAG chatbot API?
Yes. Kotlin is a strong fit when your application already runs on Android or the JVM. The integration material highlights concise syntax, strong type inference, Java interoperability, and solid networking support, which makes Kotlin well suited for authenticated API calls, JSON handling, and backend orchestration around a RAG chatbot.
Can I reuse an OpenAI-style Kotlin client with the CustomGPT.ai RAG API?
Usually, yes. The API is described as OpenAI-compatible at /v1/chat/completions, so a Kotlin client built around the chat-completions request and response pattern can often be adapted by changing the base URL and authentication details. The main difference is that responses can be grounded in your ingested knowledge base rather than a generic prompt. Evan Weber summarized the content-driven value this way: u0022I just discovered CustomGPT, and I am absolutely blown away by its capabilities and affordability! This powerful platform allows you to create custom GPT-4 chatbots using your own content, transforming customer service, engagement, and operational efficiency.u0022
Related Resources
If you’re exploring the CustomGPT.ai API in Kotlin, these resources add useful context across setup, integrations, and adjacent languages.
- CustomGPT.ai API Guide — A broader walkthrough of the CustomGPT.ai API that helps frame Kotlin-specific implementation choices.
- Objective-C iOS Guide — See how CustomGPT.ai can be used in Objective-C projects for iOS apps and mobile workflows.
- Available Integrations — Browse the current integration options for connecting CustomGPT.ai with your existing tools and platforms.
- CustomGPT.ai With Java — A useful companion for teams working across JVM languages and comparing Kotlin and Java API patterns.
- CustomGPT.ai With C++ — Explore how CustomGPT.ai API usage translates to C++ environments for lower-level or performance-focused applications.
- AI Chat Webhooks — Learn how to trigger software actions from CustomGPT.ai chat events using webhook-based automation.