OpenAI DevDay 2025: Full Breakdown of AgentKit, Codex GA, Apps SDK, and Sora 2 API
OpenAI DevDay 2025: Full Breakdown of AgentKit, Codex GA, Apps SDK, and Sora 2 API
Introduction
OpenAI’s Developer Day 2025 has officially wrapped up — and it might be the company’s biggest event since GPT-4.
Sam Altman opened the keynote with stunning stats: 4 million developers, 800 million weekly ChatGPT users, and over 6 billion tokens processed per minute through OpenAI APIs.
But the true excitement came from a wave of new releases:
AgentKit, Codex (General Availability), ChatGPT Apps SDK, and the highly anticipated Sora 2 API.
This guide breaks down everything you need to know — what each tool does, how to use it, and why it changes the future of AI development.
AgentKit: Build and Deploy AI Agents Like a Pro
What Is AgentKit?
AgentKit is a complete toolkit for building, deploying, and optimizing AI agents.
It’s built around three core modules:
- Agent Builder – a visual canvas for creating multi-agent workflows
- Connector Registry – one hub to connect all your data and tools
- ChatKit – an embeddable chat interface for apps and websites
Together, these tools make it easier than ever to move from prompt engineering to full agent engineering.
Getting Started with Agent Builder
Agent Builder provides a visual drag-and-drop editor to design, test, and version agent workflows — similar to n8n or Zapier.
How to use it:
- Log in to your OpenAI Developer Console.
- Navigate to AgentKit → Agent Builder.
- Drag logic and API nodes to design your workflow.
- Enable Guardrails for safety, jailbreak prevention, and PII filtering.
- Click Preview Run to simulate execution and publish your agent.
Highlights:
- Built-in version control
- Modular Guardrails system
- Real-time debugging
- Export to Python or JavaScript
Connector Registry: Manage All Integrations in One Place
The Connector Registry is OpenAI’s integration hub — it centralizes access to all external data and APIs within ChatGPT and the OpenAI API ecosystem.
Supported integrations include:
- Google Drive
- Dropbox
- SharePoint
- Microsoft Teams
- Custom connectors via Model Context Protocol (MCP)
Setup steps:
- Go to Global Admin Console → Connectors
- Authorize access using OAuth
- Assign permissions for your org or app
ChatKit: Bring Conversational AI Into Your App
ChatKit allows developers to embed chat-based agents directly into their products with full control over design, branding, and behavior.
Use cases:
- AI customer support bots
- Internal knowledge assistants
- Employee onboarding helpers
Example integration:
import { ChatKit } from "openai-chatkit";
const chat = new ChatKit({
apiKey: "YOUR_API_KEY",
agentId: "YOUR_AGENT_ID",
theme: "dark",
});
chat.mount("#chat-container");Codex GA: The Ultimate AI Coding Partner
1. What’s New in Codex GA
After months of preview, Codex is now officially available with three major updates:
Slack integration – collaborate with Codex directly inside team channels
Codex SDK – embed Codex capabilities into your tools and workflows
Admin console – new analytics and access controls for organizations
2. Using Codex in Slack
You can now code collaboratively with Codex inside Slack.
Simply tag it in a thread:
@Codex generate a Python script that monitors CPU usage every 5 seconds.Codex will instantly reply with annotated, ready-to-use code — no context switching required.
3. Codex SDK Example
Integrate Codex directly into your workflow with the SDK:
import { Codex } from "openai-codex-sdk";
const codex = new Codex({ apiKey: process.env.OPENAI_API_KEY });
const result = await codex.run({
language: "python",
prompt: "Write a script that sends an email report of server uptime daily."
});
console.log(result.code);ChatGPT Apps SDK: Build Native Apps Inside ChatGPT
The new Apps SDK allows developers to create interactive, conversational apps directly within ChatGPT.
It’s built on top of the Model Context Protocol (MCP) — an open standard that defines how ChatGPT connects to external tools and data.
Quick start:
Go to OpenAI Developer Hub
→ “Create ChatGPT App”
Define your app logic (JS/TS)
Design the UI schema (JSON)
Test locally and submit for review
Example use cases:
Connect your product (like Canva, Coursera, Figma) directly inside ChatGPT
Build AI-powered education, design, or productivity tools
Reach 800M+ ChatGPT users with your own branded app
Apps SDK is open-source and currently in developer preview.
Sora 2 API: Text-to-Video, Evolved
1. Overview
Sora 2 represents OpenAI’s next leap in generative video.
Through the new Video API, developers can now create, remix, and manage videos entirely via code.
Available endpoints:
| Endpoint | Function |
|---|---|
create | Start a new video generation task |
get | Check generation status |
download | Download MP4 output |
list | View all generated videos |
delete | Remove a specific video |
2. Example: Creating a Video with Sora 2
import openai
openai.api_key = "YOUR_API_KEY"
video = openai.Video.create(
prompt="A golden retriever surfing at sunset",
model="sora-2"
)
print(video["status"])Once completed:
openai.Video.download(video["id"], output_path="output.mp4")Model Variants:
| Model | Description | Ideal Use |
|---|---|---|
| Sora 2 | Fast and flexible | Prototyping, social content |
| Sora 2 Pro | High-fidelity, cinematic quality | Ads, film production |
Reinforcement Fine-Tuning (RFT)
RFT gives developers deep control over reasoning models.
Currently available for o4-mini and GPT-5 (private beta), it introduces:
Custom tool calls – train models to choose the right tool at the right time
Custom graders – define your own evaluation metrics
This allows tailored fine-tuning focused on real-world performance, not just accuracy.
Pricing and Availability
| Product | Status | Notes |
|---|---|---|
| Agent Builder | Beta | Free for all developers |
| Connector Registry | Limited rollout | Enterprise & Edu only |
| ChatKit | Public | Available now |
| Apps SDK | Developer Preview | Open source |
| Sora 2 API | General Availability | Sora 2 / Pro options |
| Codex SDK | General Availability | GPT-5-Codex model |
Developer Recommendations
If you’re building with AI, this is your moment.
Want multi-agent automation? → Try AgentKit + Guardrails
Want chat features in your app? → Use ChatKit
Want to build inside ChatGPT? → Start with Apps SDK
Want next-gen video generation? → Explore Sora 2 API
OpenAI also confirmed that Workflows API and Agent Deployment options are coming soon — making AI deployment as simple as web hosting.
Conclusion
OpenAI DevDay 2025 marks a turning point:
From using models to building with them.
From chatbots to full AI ecosystems.
AgentKit, Codex GA, Apps SDK, and Sora 2 API together redefine what’s possible for developers — empowering anyone to create intelligent, multimodal, production-ready AI systems.
Resources
Frequently Asked Questions (FAQ)
1. What is AgentKit and how can it be used?
AgentKit is a complete toolkit for building, deploying, and optimizing AI agents. It includes the Agent Builder, Connector Registry, and ChatKit, enabling developers to create complex AI workflows with ease. It is ideal for automating tasks, integrating with third-party APIs, and creating conversational interfaces.
2. What is the difference between Codex and GPT-5 Codex?
Codex is a specialized version of GPT-3.5/4 focused on code generation. GPT-5 Codex is the next iteration, offering more powerful reasoning, tool integration, and context handling for coding tasks. Codex is better suited for automated coding workflows and integration with IDEs, while GPT-5 Codex excels at more complex tasks.
3. How can I start using ChatKit in my app?
To use ChatKit, you’ll need to integrate the ChatKit SDK into your web or mobile application. After importing the SDK, you can customize the chat UI and define the logic for your AI assistant. For detailed instructions, refer to the ChatKit Documentation.
4. What can Sora 2 API be used for?
Sora 2 API enables the generation of realistic videos based on text prompts or images. This can be used in creative fields such as social media content creation, marketing, or product demonstrations. Sora 2 offers a Pro version for high-quality video generation, and a Standard version for fast, prototyping needs.
5. Is there any pricing for these new OpenAI tools?
Most of the new tools like ChatKit, Codex SDK, and AgentKit are part of the OpenAI platform and are included in the existing standard API pricing. Specific pricing for Sora 2 API and advanced Codex features may vary, so it’s recommended to check the pricing page for the latest updates.