404 Resource not found when calling GPT-5-Chat via Azure AI Foundry inference endpoint

Question

What I’ve tried:

Verified the endpoint is correct and ends with /v1.

Confirmed the key is from the Foundry inference deployment (not Azure OpenAI).

Tried both the OpenAI Python SDK and cURL.

Ensured the model name in the request is exactly gpt-5-chat.

Tested immediately after deployment and waited >10 minutes in case of propagation delay.

Attempted both Authorization: Bearer <key> and api-key: <key> headers.

Sample request (PowerShell):

powershell
Copy
$endpoint = "https://sagul-me43r8sb-swedencentral.services.ai.azure.com/v1/chat/completions"
$key      = "<FOUNDRY_INFERENCE_KEY>"

$body = @{
  model    = "gpt-5-chat"
  messages = @(
    @{ role = "system"; content = "You are helpful." },
    @{ role = "user";   content = "Say hello" }
  )
  max_tokens = 50
} | ConvertTo-Json -Depth 5

Invoke-RestMethod -Method Post -Uri $endpoint `
  -Headers @{ "api-key" = $key; "Content-Type" = "application/json" } `
  -Body $body

Error returned:

json
Copy
{"error":{"code":"404","message":"Resource not found"}}

I need guidance on:

Whether api-key authentication is supported for Foundry inference endpoints.

If there’s a configuration step required in Azure AI Foundry for the endpoint to be usable with the SDK.

• Any known issues with gpt-5-chat in the Sweden Central region.What I’ve tried:
  • Verified the endpoint is correct and ends with /v1.
  • Confirmed the key is from the Foundry inference deployment (not Azure OpenAI).
  • Tried both the OpenAI Python SDK and cURL.
  • Ensured the model name in the request is exactly gpt-5-chat.
  • Tested immediately after deployment and waited >10 minutes in case of propagation delay.
  • Attempted both Authorization: Bearer <key> and api-key: <key> headers.
  Sample request (PowerShell):

    powershell
    Copy
    $endpoint = "https://sagul-me43r8sb-swedencentral.services.ai.azure.com/v1/chat/completions"
  

$key = "<FOUNDRY_INFERENCE_KEY>"

$body = @{ model = "gpt-5-chat" messages = @( @{ role = "system"; content = "You are helpful." }, @{ role = "user"; content = "Say hello" } ) max_tokens = 50 } | ConvertTo-Json -Depth 5

Invoke-RestMethod -Method Post -Uri $endpoint -Headers @{ "api-key" = $key; "Content-Type" = "application/json" } -Body $body

  
  **Error returned:**
  
  ```yaml
  json
  Copy
  {"error":{"code":"404","message":"Resource not found"}}

I need guidance on:

• Whether api-key authentication is supported for Foundry inference endpoints.
• If there’s a configuration step required in Azure AI Foundry for the endpoint to be usable with the SDK.
• Any known issues with gpt-5-chat in the Sweden Central region.

Answer 1

Hi sagul jafarullah

Here is the analysis based on your inputs.

Region Availability

GPT-5 is currently supported for global standard deployment for East US 2 and Sweden central Global Standard and Data zone deployment.

https://learn.microsoft.com/en-us/azure/ai-foundry/openai/how-to/reasoning?tabs=gpt-5%2Cpython-secure%2Cpy#availability

Endpoint format

The endpoint used in your code is using v1/chat completion and not using api version too

  $endpoint = "https://sagul-me43r8sb-swedencentral.services.ai.azure.com/v1/chat/completions"

As per documentation

Suggested syntax for text chat completion is as below

POST https://{resource}.services.ai.azure.com/models/chat/completions?api-version=2024-05-01-preview
{
  "modalities": [
    "text"
  ],
  "messages": [
    {
      "role": "system",
      "content": "You are a helpful assistant"
    },
    
     "role": "user", 
     "content": "Explain Riemann's conjecture" 
    }
  "frequency_penalty": 0,
  "presence_penalty": 0,
  "temperature": 0,
  "top_p": 0,
  "seed": 21,
  "model": "my-model-name"
}]

Correct Usage in Azure OpenAI SDK

import os
import base64
from openai import AzureOpenAI

endpoint = os.getenv("ENDPOINT_URL", "https://<yourazureopaniname>.openai.azure.com/") deployment = os.getenv("DEPLOYMENT_NAME", "gpt-5")
subscription_key = os.getenv("AZURE_OPENAI_API_KEY", "REPLACE_WITH_YOUR_KEY_VALUE_HERE")

# Initialize Azure OpenAI client with key-based authentication
client = AzureOpenAI(
    azure_endpoint=endpoint,
    api_key=subscription_key,
    api_version="2025-01-01-preview",
)

# IMAGE_PATH = "YOUR_IMAGE_PATH"
# encoded_image = base64.b64encode(open(IMAGE_PATH, 'rb').read()).decode('ascii')

# Prepare the chat prompt
chat_prompt = [
    {
        "role": "developer",
        "content": [
            {
                "type": "text",
                "text": "You are an AI assistant that helps people find information."
            }
        ]
    },
    {
        "role": "user",
        "content": [
            {
                "type": "text",
                "text": "How would earth look to aliens."
            }
        ]
    }
]

# Include speech result if speech is enabled
messages = chat_prompt

# Generate the completion
completion = client.chat.completions.create(
    model=deployment,
    messages=messages,
    max_completion_tokens=16384,
    stop=None,
    stream=False
)

print(completion.to_json())
    

Ask

Could you also confirm that

You had O3 access prior or GPT 5 image access through Gated form already.

Thank you