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AI Infrastructure

AI EmbeddingsVector embeddings for semantic search and RAG

The Helix AI Embeddings API turns text into vector embeddings for semantic search, RAG (retrieval-augmented generation), clustering, and recommendation systems. Powered by open-source sentence-transformers — production-grade quality without OpenAI's ada pricing.

  • Free tier with 100 requests/month
  • Fast, cached responses
  • 99.9% uptime target
  • Standard REST + JSON
Interactive Demo
Embeddings Similarity Tester

What is the AI Embeddings API?

The Helix AI Embeddings API turns text into vector embeddings for semantic search, RAG (retrieval-augmented generation), clustering, and recommendation systems. Powered by open-source sentence-transformers — production-grade quality without OpenAI's ada pricing.

How it works

  1. 1POST one or more strings to /embed — receive an array of float vectors.
  2. 2Choose between all-MiniLM-L6-v2 (384 dim, fast) or all-mpnet-base-v2 (768 dim, better quality).
  3. 3POST /similarity to get cosine similarity between two texts directly.
  4. 4Batch up to 100 texts per request — 10x faster than individual calls.
  5. 5Multilingual support via /embed/multilingual using paraphrase-multilingual-mpnet-base-v2.

Endpoints

3 REST endpoints, all returning consistent JSON.

POST
/embed

Generate embeddings for text(s)

POST
/similarity

Compute cosine similarity between texts

GET
/models

List available models

Code in 5 languages

Copy and paste into your project. Replace YOUR_API_KEY with your RapidAPI key.

// AI Embeddings API
const response = await fetch(
  "https://ai-embeddings-by-helix-api.p.rapidapi.com/embed",
  {
    method: "POST",
    headers: {
      "X-RapidAPI-Key": "YOUR_API_KEY",
      "X-RapidAPI-Host": "ai-embeddings-by-helix-api.p.rapidapi.com",
      "Content-Type": "application/json"
    },
    body: JSON.stringify({ "query": "your input" })
  }
);

const data = await response.json();
console.log(data);

What developers build with this API

Real use cases from production deployments.

1

Semantic Search That Actually Works

Replace keyword search (Postgres full-text, Elasticsearch BM25) with vector search. 'cheap laptop for college' finds 'budget notebook for students' — meaning, not exact words.

2

RAG Pipelines

Embed your docs, store in pgvector/Pinecone/Weaviate, retrieve top-K by similarity, feed to LLM. The backbone of every modern AI chatbot.

3

Content Recommendations

Embed every product/article/song, recommend N nearest neighbors. Spotify and Netflix do this — now you can too in 10 lines of code.

4

Duplicate Detection

Find near-duplicates in support tickets, customer reviews, or job listings. Cosine similarity > 0.9 = likely duplicates.

5

Content Clustering

Embed 10,000 customer feedback items, run k-means, get 20 emerging themes. No manual tagging required.

Pricing

All tiers include this API. No credit card for free tier.

BASIC

Free

  • 100 reqs/month
  • Hard limit
  • ✓ All endpoints
Most Popular

PRO

$9.99/mo

  • 10,000/month
  • +$0.005 each
  • ✓ All endpoints

ULTRA

$29.99/mo

  • 100,000/month
  • +$0.002 each
  • ✓ All endpoints

MEGA

$99.99/mo

  • 1,000,000/month
  • +$0.001 each
  • ✓ All endpoints

View all 20 APIs included →

Frequently asked questions

Real answers to questions developers ask before integrating.

Which model should I use?
all-MiniLM-L6-v2 (384d) is fast and good enough for 95% of use cases. Use all-mpnet-base-v2 (768d) only when you need the absolute best quality.
How does this compare to OpenAI's text-embedding-3?
Quality is 5-10% lower than text-embedding-3-large on benchmarks, but we're 50x cheaper. For most apps you'll never notice the difference.
What's the max input length?
512 tokens (~400 words) per text. Longer text is auto-truncated. For long documents, chunk first then average the vectors.
Can I get embeddings for non-English text?
Yes — use /embed/multilingual which supports 50+ languages with cross-lingual alignment (English query can find Spanish documents).
How fast is batching?
100 texts in one call: ~400ms total. Individually: ~80ms × 100 = 8s. Always batch when possible.
Are embeddings deterministic?
Yes — same input always produces the same vector. Safe for caching.

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