---
title: "Nebius"
description: "Nebius API conversion guide - OpenAI-compatible format, parameter handling, streaming, embeddings, and special features"
icon: "n"
---

## Overview

Nebius is an **OpenAI-compatible provider** offering comprehensive API support. Bifrost delegates to the OpenAI implementation with standard parameter filtering. Key features:
- **Full OpenAI compatibility** - Chat, text completion, embeddings, and responses
- **Streaming support** - Server-Sent Events with delta-based updates
- **AI Project ID** - Nebius-specific project identifier support
- **Tool calling** - Complete function definition and execution
- **Parameter filtering** - Removes unsupported OpenAI-specific fields

### Supported Operations

| Operation | Non-Streaming | Streaming | Endpoint |
|-----------|---------------|-----------|----------|
| Chat Completions | ✅ | ✅ | `/v1/chat/completions` |
| Responses API | ✅ | ✅ | `/v1/chat/completions` |
| Text Completions | ✅ | ✅ | `/v1/completions` |
| Embeddings | ✅ | - | `/v1/embeddings` |
| Image Generation | ✅ | - | `/v1/images/generations` |
| List Models | ✅ | - | `/v1/models` |
| Speech (TTS) | ❌ | ❌ | - |
| Transcriptions (STT) | ❌ | ❌ | - |
| Files | ❌ | ❌ | - |
| Batch | ❌ | ❌ | - |

<Note>
**Unsupported Operations** (❌): Speech, Transcriptions, Files, and Batch are not supported by the upstream Nebius API. These return `UnsupportedOperationError`.
</Note>

---

# 1. Chat Completions

## Request Parameters

Nebius supports all standard OpenAI chat completion parameters. For full parameter reference and behavior, see [OpenAI Chat Completions](/providers/supported-providers/openai#1-chat-completions).

### Nebius-Specific Parameters

**ai_project_id (Optional):**

Nebius allows specifying a project ID for resource organization:

<Tabs>
<Tab title="Gateway">

```bash
curl -X POST http://localhost:8080/v1/chat/completions \
  -H "Content-Type: application/json" \
  -d '{
    "model": "nebius/model-name",
    "messages": [...],
    "ai_project_id": "project-123"
  }'
```

</Tab>
<Tab title="Go SDK">

```go
request := &schemas.BifrostChatRequest{
    Model: "model-name",
    Input: messages,
    Params: &schemas.ChatParameters{
        ExtraParams: map[string]interface{}{
            "ai_project_id": "project-123",
        },
    },
}
```

</Tab>
</Tabs>

The `ai_project_id` is appended as a query parameter to the request URL.

### Filtered Parameters

Removed for Nebius compatibility:
- `prompt_cache_key` - Not supported
- `verbosity` - Anthropic-specific
- `store` - Not supported
- `service_tier` - Not supported

Nebius supports all standard OpenAI message types, tools, responses, and streaming formats. For details on message handling, tool conversion, responses, and streaming, refer to [OpenAI Chat Completions](/providers/supported-providers/openai#1-chat-completions).

---

# 2. Responses API

Converted internally to Chat Completions:

```
ResponsesRequest → ChatRequest → ChatCompletion → ResponsesResponse
```

Same parameter support and message handling as Chat Completions. Supports ai_project_id via extra_params.

---

# 3. Text Completions

Nebius supports legacy text completion format:

| Parameter | Mapping |
|-----------|---------|
| `prompt` | Direct pass-through |
| `max_tokens` | max_tokens |
| `temperature`, `top_p` | Direct pass-through |
| `stop` | Stop sequences |
| `frequency_penalty`, `presence_penalty` | Penalty parameters |

---

# 4. Embeddings

Nebius supports text embeddings:

| Parameter | Notes |
|-----------|-------|
| `input` | Text or array of texts |
| `model` | Embedding model name |
| `encoding_format` | "float" or "base64" |
| `dimensions` | Custom output dimensions (optional) |

Response returns embedding vectors with usage information.

---

# 5. Image Generation

**Request Parameters**

| Parameter | Type | Required | Notes |
|-----------|------|----------|-------|
| `model` | string | ✅ | Model identifier |
| `prompt` | string | ✅ | Text description of the image to generate |
| `size` | string | ❌ | Image size in WxH format (e.g., `"1024x1024"`). Converted to separate `width` and `height` integers |
| `output_format` | string | ❌ | Output format: `"png"`, `"jpeg"`, `"webp"`. Note: `"jpeg"` is converted to `"jpg"` |
| `response_format` | string | ❌ | Response format: `"url"` or `"b64_json"` |
| `seed` | int | ❌ | Seed for reproducible generation  |
| `negative_prompt` | string | ❌ | Negative prompt |
| `num_inference_steps` | int | ❌ | Number of inference steps |
| `extra_params` | object | ❌ | Nebius-specific parameters (see below) |

**Extra Parameters (via `extra_params`)**

| Parameter | Type | Notes |
|-----------|------|-------|
| `guidance_scale` | int | Guidance scale (0-100) |
| `ai_project_id` | string | Nebius project ID (added as query parameter) |

---

**Request Conversion**

- **Model & Prompt**: `bifrostReq.Model` → `req.Model` (pointer), `bifrostReq.Input.Prompt` → `req.Prompt` (pointer)
- **Size Conversion**: `params.size` (WxH format like `"1024x1024"`) is split into:
  - `width`: Integer extracted from first part (e.g., `1024`)
  - `height`: Integer extracted from second part (e.g., `1024`)
- **Output Format**: 
  - `params.output_format` → `req.ResponseExtension`
  - Special conversion: `"jpeg"` → `"jpg"` (Nebius uses `"jpg"` not `"jpeg"`)
- **Response Format**: `params.response_format` → `req.ResponseFormat` (passed directly: `"url"` or `"b64_json"`)
- **Seed & Negative Prompt**: `params.seed` → `req.Seed`, `params.negative_prompt` → `req.NegativePrompt` (passed directly)
- **Num Inference Steps**: `params.num_inference_steps` → `req.NumInferenceSteps` (passed directly)
- **Extra Parameters**:
  - `guidance_scale` → `req.GuidanceScale` (int pointer)
  - `ai_project_id` → Added as query parameter `?ai_project_id={value}` to the request URL

**Response Conversion**

- **Image Data**: Each item in `response.data[]` → `ImageData` with:
  - `url`: From `data[].url`
  - `b64_json`: From `data[].b64_json`
  - `revised_prompt`: From `data[].revised_prompt`
  - `index`: Sequential index (0, 1, 2, ...)
- **ID**: `response.id` → `response.ID`
- **Provider**: Set to `nebius` in `ExtraFields`

**Endpoint**: `/v1/images/generations`

**Streaming**: Image generation streaming is not supported by Nebius.

---

# 6. List Models

Lists available Nebius models with capabilities and context lengths.

---

## Unsupported Features

| Feature | Reason |
|---------|--------|
| Speech/TTS | Not offered by Nebius API |
| Transcription/STT | Not offered by Nebius API |
| Batch Operations | Not offered by Nebius API |
| File Management | Not offered by Nebius API |

---

## Caveats

<Accordion title="Cache Control Stripped">
**Severity**: Medium
**Behavior**: Cache control directives are removed from messages
**Impact**: Prompt caching features don't work
**Code**: Stripped during JSON marshaling
</Accordion>

<Accordion title="Parameter Filtering">
**Severity**: Low
**Behavior**: OpenAI-specific fields filtered out
**Impact**: prompt_cache_key, verbosity, store removed
**Code**: filterOpenAISpecificParameters
</Accordion>

<Accordion title="User Field Size Limit">
**Severity**: Low
**Behavior**: User field > 64 characters silently dropped
**Impact**: Longer user identifiers are lost
**Code**: SanitizeUserField enforces 64-char max
</Accordion>