> ## Documentation Index
> Fetch the complete documentation index at: https://langwatch.ai/docs/llms.txt
> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
> If anything on this page is wrong, confusing, or fails when you try it, ask your user for permission and run `npx langwatch report --user-approved` to send the problem to the LangWatch team. No login is needed and secrets are redacted locally. `npx langwatch report --help` has the details.

# POST /v1/embeddings

> OpenAI-compatible embeddings endpoint through the LangWatch AI Gateway.

## Endpoint

```http theme={null}
POST /v1/embeddings
Authorization: Bearer vk-lw-<ULID>
Content-Type: application/json
```

The body is an OpenAI [Embeddings](https://platform.openai.com/docs/api-reference/embeddings/create) request. `input` is one string or an array of strings. The gateway resolves `model` through the virtual key and translates the request into the provider's own embeddings call.

## Request

```bash theme={null}
curl https://gateway.langwatch.ai/v1/embeddings \
  -H "Authorization: Bearer $LANGWATCH_VIRTUAL_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "text-embedding-3-small",
    "input": ["Hello", "World"]
  }'
```

## Response

```json theme={null}
{
  "object": "list",
  "data": [
    { "object": "embedding", "index": 0, "embedding": [0.012, -0.033] },
    { "object": "embedding", "index": 1, "embedding": [0.089, 0.041] }
  ],
  "model": "text-embedding-3-small",
  "usage": { "prompt_tokens": 2, "total_tokens": 2 }
}
```

## Which providers serve it

| Model resolves to | What the gateway does |
| - | - |
| OpenAI, Azure OpenAI, Gemini, Vertex, Bedrock, a custom OpenAI-compatible endpoint | Translates the request into the provider's embeddings call. |
| Voyage (`voyage/` prefix) | Forwards the OpenAI-shaped body to Voyage as written, with the bare model name. Voyage credentials serve embeddings only; any other route on them answers `400 bad_request`. |
| Anthropic | Has no embeddings API. The provider's own rejection is forwarded. |

## Parameters the gateway changes or refuses

| Parameter | What the gateway does |
| - | - |
| `model` | Resolved through the key's aliases, allowlist and routing policy, then rewritten to the provider's model id. Missing: `400 missing_model`. Outside the allowlist: `400 model_not_allowed`. |
| `input` | Read and passed to the provider as one text or a list of texts. A body that does not parse as an embeddings request answers `400 bad_request`. |

The `X-LangWatch-End-User-Id`, `X-LangWatch-Metadata` and `Traceparent` request headers work as on [Chat Completions](https://langwatch.ai/docs/ai-gateway/api/chat-completions.md#request-headers-the-gateway-reads).

## Response headers

The same set as [Chat Completions](https://langwatch.ai/docs/ai-gateway/api/chat-completions.md#response-headers): `X-LangWatch-Gateway-Version`, `X-LangWatch-Gateway-Request-Id`, `X-LangWatch-Fallback-Count`, `X-LangWatch-Budget-Warning`, `Traceparent`, `X-LangWatch-Heartbeat-Active`, and `X-LangWatch-Provider` on a forwarded provider error. `X-LangWatch-Handled-Error` carries the `error.code` when the gateway wrote the error itself, and is removed from a forwarded provider response.

## Streaming

This endpoint does not stream. A `stream` field in the body is not read.

## Errors

Codes this endpoint raises before the provider is called: `missing_model`, `model_not_allowed`, `model_provider_not_bound`, `model_not_recognized`, `bad_request`, `end_user_required`. All answer `400`. A provider's own error is forwarded with its status and body. The full table is on [Errors](https://langwatch.ai/docs/ai-gateway/api/errors.md).

**Also check:** [Fallback chains](https://langwatch.ai/docs/ai-gateway/providers/fallback-chains.md), [Model aliases](https://langwatch.ai/docs/ai-gateway/model-aliases.md).


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