sentence-transformers

A Python module for working with embedding and reranking models

Also known as
sentence-transformers

Available worldwide

What is sentence-transformers?

Python toolkit for generating semantic embeddings from text, images, audio, and video using transformer-based neural networks. Supports dense embedding models, cross-encoder rerankers for scoring and ranking, and late-interaction multi-vector models for advanced retrieval tasks.

Independently observed

sentence-transformers pricing

We don't have sentence-transformers's full plan breakdown yet (its pricing page resisted automated reading). Here's what we could confirm. Always check live pricing for exact numbers.

What sentence-transformers does

The capabilities that matter for embeddings apis, normalised so it lines up with every alternative. “-” means we haven't confirmed it, not that it's missing.

Capabilities
Architecture model
Open weights local
Matryoshka representation learning for dimension truncation
-
Multilingual support across 100 plus languages
-
Binary and scalar quantization for memory reduction
-
Cross encoder reranker API offered
✓
Late interaction architecture colbert v2
✓
Massive context window greater than 8k tokens
-
Multi modal image and text joint embeddings
✓
Task specific prefixes query vs document instructions
-
Zero data retention training opt out enterprise
-
SOC2 type ii
-
Mit or apache permissive oss license
-
Pricing model
Free open weights
Independently observed

Platform & deployment

Independently observed
Deployment
  • Self-hosted

Integrations (1)

Independently observed
  • Hugging Face Hub

Security & compliance

Known vulnerabilities: 1 (1 in the last 12 months), max severity CRITICAL sourcea count reflects scale & disclosure, not quality

sentence-transformers FAQ

Common questions about sentence-transformers, answered from independent, dated evidence.

What is sentence-transformers?

Python toolkit for generating semantic embeddings from text, images, audio, and video using transformer-based neural networks. Supports dense embedding models, cross-encoder rerankers for scoring and ranking, and late-interaction multi-vector models for advanced retrieval tasks. It is indexed under Embeddings Apis.

Source: https://www.sbert.net

Is sentence-transformers free to use?

sentence-transformers is open source, so it can be self-hosted and used at no licence cost. It is released under the Apache-2.0 licence. Pricing changes often, so verify at source before relying on it.

Source: https://www.sbert.net

Can sentence-transformers be self-hosted?

Yes. sentence-transformers can be deployed self-hosted, so it does not have to run on the vendor's infrastructure.

Source: https://www.sbert.net

Is sentence-transformers open source?

Yes. sentence-transformers is published under the Apache-2.0 licence, a permissive licence that generally allows commercial use and modification. Licence terms can change between releases, so verify against the repository for the version you intend to use.

Source: https://github.com/huggingface/sentence-transformers

sentence-transformers alternatives

Other embeddings apis we track, ranked by the same independent score.

All sentence-transformers alternatives, ranked →

Compare sentence-transformers

Side by side against other embeddings apis, attribute by attribute, with a source on every value.

Independent · unbought · dated

The vioscaleAI score: one lens on the evidence

Not user reviews and not a paid placement: a confidence-weighted blend of the independent signals below (adoption, activity, security posture, and more), which you can sort and re-weight yourself. Vendors can correct their listing but can never move their rank, and stars are weighted low as a vanity metric. It is one way to read the evidence for sentence-transformers, not the verdict.

Balanced composite 59 / 100
medium · 54%
Signal contributions to the composite score
SignalScoreWeightContributionEvidence
Development activity630.148.5✓
Release cadence850.086.9✓
Capabilities580.084.6✓
Stars810.053.8✓
Dependent projects620.053.3✓
Integrations90.050.5✓
Security posture00.120.0-
Package downloads00.040.0-
Security score00.050.0-
Developer Q&A activity00.140.0-

Computed . Re-weight it by intent, or see the full method.

All data & sourcesshow ↓

Every value we hold, with its source, retrieval date, and confidence. This is the evidence behind the score: don't trust it, verify it.

Activity

AttributeValueEvidence
Commits last 30d100mediumsource · 2026-10-14 · 65%

Adoption

AttributeValueEvidence
Github stars19,174highsource · 2026-10-14 · 90%
Dependent repos5,182highsource · 2026-10-14 · 85%

Content

AttributeValueEvidence
Faq4 itemsmediumsource · 2026-09-10 · 69%

Features

AttributeValueEvidence
CapabilitiesPricing model: free_open_weights · Architecture model: open_weights_local · Cross encoder reranker api offered: Yes · Late interaction architecture colbert v2: Yes · Multi modal image and text joint embeddings: Yesmediumsource · 2026-10-14 · 60%

Integrations

AttributeValueEvidence
Count1mediumsource · 2026-08-21 · 60%

Language

AttributeValueEvidence
PrimaryPythonhighsource · 2026-10-14 · 90%

License

AttributeValueEvidence
SpdxApache-2.0highsource · 2026-10-14 · 95%

Market

AttributeValueEvidence
AvailabilityPrimaryMarkets: … · AvailabilityScope: global · AvailableCountries: … · NotAvailableCountries: …highsource · 2026-08-21 · 75%

Pricing

AttributeValueEvidence
Free tierYesmediumsource · 2026-10-14 · 60%
Modelopen_sourcemediumsource · 2026-10-14 · 60%
Price levelfreemediumsource · 2026-10-14 · 60%
TransparentYesmediumsource · 2026-10-14 · 60%

Release

AttributeValueEvidence
History20 itemsmediumsource · 2026-10-14 · 70%
Cadence days27mediumsource · 2026-10-14 · 70%

Security

AttributeValueEvidence
VulnerabilitiesCount: 1 · Source: https://advisories.ecosyste.ms/api/v1/advisories?ecosystem=pypi&package_name=sentence-transformers&per_page=100 · Last 12m: 1 · Max severity: CRITICALhighsource · 2026-10-14 · 90%
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