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Embeddings API

Generate vector embeddings for semantic search and RAG applications with Amazon Bedrock embedding models through an OpenAI-compatible interface.

Why Choose the Embeddings API?

  • Semantic Search
    Find content based on meaning and context, not just exact words. For knowledge bases and document retrieval.

  • High Performance
    Amazon Bedrock embedding models deliver fast vectors optimized for production workloads. Batch processing for large-scale operations.

  • Flexible Dimensions
    Choose vector dimensions that match your needs. Balance accuracy and storage/compute costs with model-specific dimension control.

  • Multimodal Embeddings
    Process images, videos, audio, and PDF documents alongside text. Unified embeddings for cross-modal search using base64 data URI input.

Available Endpoints

Endpoint Method What It Does Powered By MCP Tool
/v1/embeddings POST Transform text and multimodal content into semantic vectors Amazon Bedrock Embedding Models openai_embedding

Feature Compatibility

Feature Status Notes
Input Types
Text input (single string) Full support for text embeddings
Multimodal input Image, audio, video, document (image + text)
Multiple input (batch array) Process multiple inputs efficiently
Token array input Array of token integers not supported
Output Formats
Float vectors Standard floating-point arrays
Base64 encoding Base64-encoded float32 arrays
Model Parameters
dimensions override Some models support dimension reduction
encoding_format Choose float or base64
Extra model-specific params Extra model-specific parameters not supported by the OpenAI API
Usage tracking
Input text tokens Reported as billed by Amazon Bedrock; zero on models and inputs for which Bedrock returns no token count

Legend:

  • Supported — Fully compatible with OpenAI API
  • Model-Dependent — Behavior depends on the model or backend; check the Notes column
  • Unsupported — Not available in this implementation
  • Extra Feature — Enhanced capability beyond OpenAI API

Model Support

Any Amazon Bedrock model that produces embeddings answers on this route — the Amazon Titan Embed and Amazon Nova embedding families, Cohere Embed, and TwelveLabs Marengo. A model that produces something else is refused with 400, naming it.

To list the models this deployment serves on this route, call search_models with route=openai_embedding. Which of them accept images, video or audio rather than text alone is covered under Multimodal Embeddings.

No Bedrock Mantle models here

Bedrock Mantle serves chat models only. Embeddings always come from the classic bedrock-runtime catalogue, whether or not Mantle is enabled.

Model Name Aliases

Cohere models carry the dotted version their own API publishes, so the name you already send resolves without change:

  • embed-v4.0cohere.embed-v4:0
  • embed-english-v3.0cohere.embed-english-v3

Advanced Features

Embedding a Corpus in Bulk

A large corpus does not have to be embedded on the request path. Upload the requests as a file and run them through the Batch API against /v1/embeddings: they run without a connection held open, at the published batch rate, and the vectors are read back from the result file. One batched request embeds one input, and its vectors come back as numbers.

Provider-Specific Parameters

Access advanced embedding capabilities by passing provider-specific parameters directly in your requests. These parameters are forwarded to Amazon Bedrock and allow you to access features unique to each embedding model provider.

Documentation: Bedrock Embedding Model Parameters

How It Works:

Add provider-specific fields at the top level of your request body alongside standard OpenAI parameters. The API automatically forwards these to the appropriate model provider via Amazon Bedrock.

Examples:

Cohere Embed v4 - Input Type:

{
  "model": "cohere.embed-v4:0",
  "input": "Semantic search transforms how we find information",
  "input_type": "search_query"
}

Amazon Titan Embed v2 - Normalization:

{
  "model": "amazon.titan-embed-text-v2:0",
  "input": "Product description for similarity matching",
  "normalize": true
}

Configuration Options:

Option 1: Per-Request

Add provider-specific parameters directly in your request body (as shown in examples above).

Option 2: Server-Wide Defaults

Configure default parameters for specific models via the DEFAULT_MODEL_PARAMS environment variable:

export DEFAULT_MODEL_PARAMS='{
  "cohere.embed-v4:0": {
    "input_type": "search_document",
    "truncate": "END"
  }
}'

Note: Per-request parameters override server-wide defaults.

Behavior:

  • Compatible parameters: Forwarded to the model and applied
  • Unsupported parameters: Return HTTP 400 with an error message

Multimodal Embeddings

Go beyond text! Supported models can process images, videos, and audio through base64 data URI input. This enables powerful cross-modal search and similarity features.

Input Format

Multimodal content is passed as base64-encoded data URIs:

data:<mime-type>;base64,<base64-encoded-content>

Example: Image Embedding

# First, encode your image to base64
IMAGE_B64=$(base64 -w 0 image.jpg)

# Send the embedding request
curl -X POST "$BASE/v1/embeddings" \
  -H "Authorization: Bearer $OPENAI_API_KEY" \
  -H "Content-Type: application/json" \
  -d "{
    \"model\": \"amazon.nova-2-multimodal-embeddings-v1:0\",
    \"input\": \"data:image/jpeg;base64,$IMAGE_B64\"
  }"

Example: Video Embedding

Option 1: Base64-encoded video (for small files)

# First, encode your video to base64
VIDEO_B64=$(base64 -w 0 video.mp4)

# Send the embedding request
curl -X POST "$BASE/v1/embeddings" \
  -H "Authorization: Bearer $OPENAI_API_KEY" \
  -H "Content-Type: application/json" \
  -d "{
    \"model\": \"amazon.nova-2-multimodal-embeddings-v1:0\",
    \"input\": \"data:video/mp4;base64,$VIDEO_B64\"
  }"

Automatic S3 Upload

When you provide Base64-encoded data that exceeds the model's size limit (or Bedrock's 25 MB quota), the server automatically stages it in S3 so the request still succeeds.

To allow this behavior, configure regional S3 buckets via AWS_S3_REGIONAL_BUCKETS in the same region as your Bedrock model. See configuration guide.

Usage Not Available for Large Inputs

Amazon Nova models report no token usage for large inputs (those exceeding the model's inline size limit): the usage field then reports zero tokens.

Large Base64 Files and Memory Configuration

While passing large files as Base64 is supported, ensure your server has sufficient memory configured. Large Base64-encoded files (especially videos) can consume significant memory during processing. Consider using S3 URLs directly for very large files, or adjust your server's memory limits accordingly.

Option 2: S3 URL (for large files)

# Send the embedding request with S3 URL
curl -X POST "$BASE/v1/embeddings" \
  -H "Authorization: Bearer $OPENAI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "amazon.nova-2-multimodal-embeddings-v1:0",
    "input": "s3://my-bucket/path/to/video.mp4"
  }'

S3 URL Requirements

When using S3 URLs directly:

  • S3 bucket must be in the same AWS region as the Bedrock model
  • The stdapi.ai server must have read access to the S3 object
  • For TwelveLabs Marengo models: S3 bucket must be in the same AWS account as the stdapi.ai server

Option 3: Files API reference (file-id:)

Reference a file previously uploaded via the Files API using the project-local file-id: URI scheme:

curl -X POST "$BASE/v1/embeddings" \
  -H "Authorization: Bearer $OPENAI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "amazon.nova-2-multimodal-embeddings-v1:0",
    "input": "file-id:file-0190c51c7de7455d9b8c2efe27dfbf67"
  }'

Example: PDF Document Embedding

For PDFs, convert each page to an image and send via inputs along with page metadata (e.g., file_name, entities) in adjacent text parts. For RAG applications, smaller chunks often improve retrieval accuracy and reduce costs.

Cohere Cohere Embed v4 (supports multiple text+image pairs in one request):

# Convert PDF pages to images (using ImageMagick or similar tool)
convert -density 150 document.pdf page-%d.jpg

# Encode each page image to base64
PAGE_1=$(base64 -w 0 page-0.jpg)
PAGE_2=$(base64 -w 0 page-1.jpg)

# Generate document embedding with metadata
curl -X POST "$BASE/v1/embeddings" \
  -H "Authorization: Bearer $OPENAI_API_KEY" \
  -H "Content-Type: application/json" \
  -d "{
    \"model\": \"cohere.embed-v4:0\",
    \"input\": [
      \"file_name: report.pdf, page: 1\",
      \"data:image/jpeg;base64,$PAGE_1\",
      \"file_name: report.pdf, page: 2\",
      \"data:image/jpeg;base64,$PAGE_2\"
    ]
  }"

TwelveLabs TwelveLabs Marengo v3 (requires exactly one text + one image per request):

Usage Not Available

TwelveLabs Marengo models do not return token usage information. The usage field in the response will always report zero tokens.

Text+Image Pairing for Marengo v3

When using twelvelabs.marengo-embed-3-0-v1:0, if you provide exactly 2 inputs where one is text and one is image, they are automatically combined into a single text_image embedding. This creates a unified multimodal representation of the text-image pair.

# Encode image to base64
IMAGE_B64=$(base64 -w 0 page-0.jpg)

# Generate text+image embedding (automatically uses text_image mode)
curl -X POST "$BASE/v1/embeddings" \
  -H "Authorization: Bearer $OPENAI_API_KEY" \
  -H "Content-Type: application/json" \
  -d "{
    \"model\": \"twelvelabs.marengo-embed-3-0-v1:0\",
    \"input\": [
      \"A diagram showing the quarterly sales report\",
      \"data:image/jpeg;base64,$IMAGE_B64\"
    ]
  }"

Mixed-Content Batching

Combine text and multimodal inputs in a single request:

curl -X POST "$BASE/v1/embeddings" \
  -H "Authorization: Bearer $OPENAI_API_KEY" \
  -H "Content-Type: application/json" \
  -d "{
    \"model\": \"cohere.embed-v4:0\",
    \"input\": [
      \"A beautiful sunset over mountains\",
      \"data:image/jpeg;base64,/9j/4AAQSkZJRg...\",
      \"Nature photography collection\"
    ]
  }"

Use Cases

  • Visual Search: Find images similar to a query image or text description
  • Video Analysis: Search and retrieve video content based on visual similarity or text descriptions
  • Audio Similarity: Find similar audio clips or match audio to text descriptions
  • Document Retrieval: Find relevant PDFs based on visual and textual content
  • Cross-Modal Recommendations: Recommend images, videos, or audio based on text queries and vice versa
  • Content Moderation: Analyze and classify multimodal content at scale

Build smarter search and recommendations! Explore available embedding models in the Models API.

Available Request Headers

This endpoint supports standard Bedrock headers for enhanced control over your requests. All headers are optional and can be combined as needed.

Content Safety (Guardrails)

Header Purpose Valid Values
X-Amzn-Bedrock-GuardrailIdentifier Guardrail ID for content filtering Your guardrail identifier
X-Amzn-Bedrock-GuardrailVersion Guardrail version Version number (e.g., 1)
X-Amzn-Bedrock-Trace Guardrail trace level disabled, enabled, enabled_full

Performance Optimization

Header Purpose Valid Values
X-Amzn-Bedrock-Service-Tier Service tier selection default, flex, priority, reserved
X-Amzn-Bedrock-PerformanceConfig-Latency Latency optimization standard, optimized

Example with headers:

curl -X POST "$BASE/v1/embeddings" \
  -H "Authorization: Bearer $OPENAI_API_KEY" \
  -H "Content-Type: application/json" \
  -H "X-Amzn-Bedrock-Service-Tier: flex" \
  -H "X-Amzn-Bedrock-PerformanceConfig-Latency: standard" \
  -d '{
    "model": "amazon.nova-2-multimodal-embeddings-v1:0",
    "input": ["Batch text 1", "Batch text 2", "Batch text 3"]
  }'

Detailed Documentation

For complete information about these headers, configuration options, and use cases, see:

Try It Now

Single text embedding:

curl -X POST "$BASE/v1/embeddings" \
  -H "Authorization: Bearer $OPENAI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "amazon.nova-2-multimodal-embeddings-v1:0",
    "input": "Semantic search transforms how we find information"
  }'

Batch processing with base64 encoding:

curl -X POST "$BASE/v1/embeddings" \
  -H "Authorization: Bearer $OPENAI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "amazon.nova-2-multimodal-embeddings-v1:0",
    "input": ["Product description", "User query", "Related content"],
    "encoding_format": "base64"
  }'