World-class text embeddings · 512 dimensions

Powerful embeddings at a fraction of the size.

Similar.dev is engineered for the highest power-to-weight ratio in embeddings: production-grade semantic quality in 512 float32 dimensions, served through an OpenAI wire-format API you can call in under a minute. Smaller vectors, smaller indexes, smaller bills.

512Dfloat32 output
6xsmaller than 3072-d indexes
100inputs per request
5yrminimum endpoint life
embed.py
from openai import OpenAI

client = OpenAI(
    api_key="sme_your_account_...",
    base_url="https://api.similar.dev/v1",
)

response = client.embeddings.create(
    model="similar.dev-en-v1-medium-512",
    input=[
        "Compact vectors for production retrieval.",
        "Same wire format. Smaller footprint.",
    ],
)

vectors = [item.embedding for item in response.data]
# 2 documents -> 2 x 512 float32 components
request POST /v1/embeddings model=similar.dev-en-v1-medium-512
usage inputs=2 prompt_tokens=14 total_tokens=14
response 200 OK dims=512 dtype=float32 latency=84ms

Model catalog

Three compact spaces. One API contract.

Every model returns 512 float32 components through the same request and response shape. Start on the English flagship, switch IDs as your corpus changes, never rewrite a client.

Flagship · English

similar.dev-en-v1-medium-512

Our highest-capacity English document embedding. The default choice for retrieval, clustering, deduplication, and semantic search over English text.

Dims512
ModeDocument
Localeen-US
Lite · English

similar.dev-en-v1-lite-512

A lighter English variant on the identical contract. Ideal for high-volume pipelines where throughput and cost dominate the decision.

Dims512
ModeDocument
Localeen-US
Lite · Multilingual

similar.dev-lang3-lite-512

One shared semantic space for English, Spanish, and Portuguese documents. Same meaning lands in nearby vectors across all three languages.

Dims512
ModeDocument
Localesen · es · pt

Why size matters

Every dimension you store, you pay for forever.

A retrieval system pays for embeddings twice: once at inference, then every hour the index stays in memory, on disk, and across replicas. At ten million documents, a 3072-dimensional float32 index is roughly 123 GB before any overhead. The same corpus at 512 dimensions is about 20 GB.

That gap is the difference between a vector database that fits on one node and one that needs a cluster. Similar.dev targets the point where quality stays high and the operational footprint stays small.

See pricing

Index footprint, 10M documents (float32)

Raw vector storage only. Illustrative arithmetic, not a benchmark.

3072-d123 GB
1024-d41 GB
768-d31 GB
similar.dev 512-d20 GB
Per vector2 KB
Per 1M docs2 GB
Per 1B docs2 TB

Fewer bytes per vector also means fewer bytes on the wire per query, faster index builds, and cheaper replicas in every region you serve.

MTEB evaluation in progress

Public benchmark scores land here.

We are running MTEB-aligned evaluation on the English flagship now. Until those numbers are published we will not show leaderboard positions, rankings, or quality superlatives. A model-specific internal multilingual evaluation for similar.dev-lang3-lite-512 is already public on the production site.

Read the published evaluation note
MTEB · Retrievalpending
MTEB · STSpending
MTEB · Clusteringpending
MTEB · Classificationpending

Published evidence

On a held-out internal multilingual retrieval benchmark spanning six language directions, top-1 retrieval ranged from 99.48% to 99.73% across 10,000 examples. Top-10 recall was 100% across those directions. This is an internal result, not MTEB or independent third-party validation. Applies to similar.dev-lang3-lite-512.

Read the evaluation note

The magic sauce

Latent-space arbitrage.

Most embedding models spend their capacity evenly across a space that meaning does not fill evenly. We treat that imbalance as an opportunity.

Similar.dev models are built with a proprietary process we call latent-space arbitrage. The premise is that semantic geometry, like any market, has mispriced regions: directions that consume dimensions while contributing little to how documents actually separate in real workloads. Our process identifies where the signal is under-valued and where the capacity is over-spent, then rebalances the space so every one of 512 dimensions carries weight it has earned.

We will not publish the method. We will publish the results, in the open, on public benchmarks, as they land. What we can say plainly today: the outcome is embedding quality that competes with far larger vectors at a fraction of the storage, bandwidth, and compute.

01
Smaller indexes

Roughly one sixth of a 3072-d footprint, before quantization.

02
Lower cost per query

Less memory per shard, fewer shards per corpus, faster nearest-neighbor scans.

03
Quality that holds

Capacity is reinvested where meaning concentrates, not spread thin.

Built to be depended on

Embeddings are infrastructure. We treat them that way.

Switching embedding models means re-embedding every document you own. We think you should never be forced into that by a deprecation notice.

Commitment 5 years

Minimum endpoint lifetime

Every model ID we publish stays callable for at least five years from launch before any retirement notice. Invest in a space knowing it will still be there.

Coming soon Custom fit

Models tuned to your corpus

Bring your own domain text and receive a compact embedding space calibrated to how your documents actually differ. Not yet available; join the interest list from the contact page.

Roadmap 7+ languages

Language-specific endpoints

Dedicated single-language models, each with its own ID and its own five-year commitment, rolling out beyond today's English and multilingual catalog.

ENESPTDEFRJAZHKOHIAR

Pricing

Start for $10. Grow without renegotiating your stack.

Developers and researchers start immediately with prepaid credits. Startup and Enterprise plans begin with a conversation so capacity, SLAs, and support are matched honestly.

Startup

Scale with guidance

Let's talk · scoped after intake

Higher volume, migration support, and early access to new model IDs, sized to your roadmap rather than a rate card.

  • Volume pricing discussion
  • Migration and re-embedding guidance
  • Early access to language endpoints
Contact
Enterprise

Invest with confidence

Let's talk · negotiated terms

SLAs, security review, and procurement-friendly billing agreed with your team. A direct intake path, not promises on a page.

  • Custom SLA discussions
  • Security and compliance review
  • Dedicated support channels
Contact

Ready when you are

One key, one base URL, one call.

Sign up, load a $10 credit, and embed your first documents before your coffee cools.

  1. Sign up and load a minimum $10 credit through Stripe.
  2. Set base_url to https://api.similar.dev/v1.
  3. Choose a model ID and send up to 100 documents per call.
  4. Store 512 floats per document. Compare with cosine similarity.