---
title: Providers
description: Supported LLM providers and model configuration.
---

# Providers

Kit supports a wide range of LLM providers through a unified `provider/model` string format.

## Supported providers

| Provider | Prefix | Description |
|----------|--------|-------------|
| **Anthropic** | `anthropic/` | Claude models (native, prompt caching, OAuth) |
| **OpenAI** | `openai/` | GPT models |
| **Google** | `google/` or `gemini/` | Gemini models |
| **Ollama** | `ollama/` | Local models |
| **Azure OpenAI** | `azure/` | Azure-hosted OpenAI |
| **AWS Bedrock** | `bedrock/` | Bedrock models |
| **Google Vertex** | `google-vertex-anthropic/` | Claude on Vertex AI |
| **OpenRouter** | `openrouter/` | Multi-provider router |
| **Vercel AI** | `vercel/` | Vercel AI SDK models |
| **Custom** | `custom/` | Any OpenAI-compatible endpoint |
| **Auto-routed** | any | Any provider from the models.dev database |

## Model string format

```bash
provider/model            # Standard format
anthropic/claude-sonnet-latest
openai/gpt-4o
ollama/llama3
google/gemini-2.5-flash
```

## Model aliases

Kit provides aliases for commonly used models:

### Anthropic Claude

```bash
claude-opus-latest        → claude-opus-4-6
claude-sonnet-latest      → claude-sonnet-4-6
claude-haiku-latest       → claude-haiku-4-5
claude-4-opus-latest      → claude-opus-4-6
claude-4-sonnet-latest    → claude-sonnet-4-6
claude-4-haiku-latest     → claude-haiku-4-5
claude-3-7-sonnet-latest  → claude-3-7-sonnet-20250219
claude-3-5-sonnet-latest  → claude-3-5-sonnet-20241022
claude-3-5-haiku-latest   → claude-3-5-haiku-20241022
claude-3-opus-latest      → claude-3-opus-20240229
```

### OpenAI GPT

```bash
o1-latest                 → o1
o3-latest                 → o3
o4-latest                 → o4-mini
gpt-5-latest              → gpt-5.4
gpt-5-chat-latest         → gpt-5.4
gpt-4-latest              → gpt-4o
gpt-4                     → gpt-4o
gpt-3.5-latest            → gpt-3.5-turbo
gpt-3.5                   → gpt-3.5-turbo
codex-latest              → codex-mini-latest
```

### Google Gemini

```bash
gemini-pro-latest         → gemini-2.5-pro
gemini-flash-latest       → gemini-2.5-flash
gemini-flash              → gemini-2.5-flash
gemini-pro                → gemini-2.5-pro
```

## Specifying a model

Via CLI flag:

```bash
kit --model openai/gpt-4o
kit -m ollama/llama3
```

Via config file:

```yaml
model: anthropic/claude-sonnet-latest
```

Via environment variable:

```bash
export KIT_MODEL="google/gemini-2.0-flash-exp"
```

## Authentication

### API keys

Set the appropriate environment variable for your provider:

```bash
export ANTHROPIC_API_KEY="sk-..."
export OPENAI_API_KEY="sk-..."
export GOOGLE_API_KEY="..."
```

Or pass it directly:

```bash
kit --provider-api-key "sk-..." --model openai/gpt-4o
```

### OAuth

For providers that support OAuth (e.g., Anthropic):

```bash
kit auth login anthropic     # Start OAuth flow
kit auth status              # Check authentication status
kit auth logout anthropic    # Remove credentials
```

### Custom provider URL

For self-hosted or proxy endpoints:

```bash
kit --provider-url "https://my-proxy.example.com/v1" --model openai/gpt-4o
```

When `--provider-url` is provided without `--model`, Kit automatically defaults to `custom/custom`:

```bash
kit --provider-url "http://localhost:8080/v1" "Hello"
```

The `custom/custom` model has zero cost, 262K context window, and supports reasoning. It routes through the `openaicompat` provider and accepts any OpenAI-compatible API endpoint.

Optionally set `CUSTOM_API_KEY` environment variable or use `--provider-api-key` for endpoints requiring authentication.

## Model database

Kit ships with a local model database that maps provider names to API configurations. You can manage it with:

```bash
kit models                   # List available models
kit models openai            # Filter by provider
kit models --all             # Show all providers
kit update-models            # Update from models.dev
kit update-models embedded   # Reset to bundled database
```
