# ZeroEntropy zerank and zembed (slim)

> Discontinued retrieval API acquired by Notion. Its embedding and reranking models remain available as open weights for self-hosting.

- Full: https://www.anchorterminal.com/tools/zeroentropy.md (~5,750 tokens) · this version ~1,430 tokens · JSON https://www.anchorterminal.com/tools/zeroentropy.json · canonical https://www.anchorterminal.com/tools/zeroentropy
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · Updated: 2026-10-04

**F · 13.8/100 · rank #450 of 452 · #7 in Embeddings & rerankers · not agent-ready · confidence medium** · superseded by Cohere Embed and Rerank (https://www.anchorterminal.com/tools/cohere-embed.min.md), Voyage AI embeddings and rerankers (https://www.anchorterminal.com/tools/voyage-ai.min.md), OpenAI embeddings (https://www.anchorterminal.com/tools/openai-embeddings.min.md)


Assessment: All four models now open weights under Apache 2.0 on Hugging Face. The hosted API was discontinued after 4 September 2026 and signups closed on 24 July 2026.

## Facts

- Kind: HTTP API · vendor: ZeroEntropy · category: Embeddings & rerankers · legal entity: ZeroEntropy, Inc. · provenance 62/100
- Endpoint: `https://api.zeroentropy.dev/v1/models/rerank` (HTTP)
- Auth: API key · pricing: Pay per use · x402: no · licence: Apache-2.0 (SDKs and model weights)
- Probe metrics: not measured yet (probes haven't run)
- Free tier: None stated
- Dimensions: zembed-1 2560, 1280, 640, 320, 160, 80 or 40
- Max context: Not published in tokens. Requests cap at 5,000,000 bytes
- Languages: Multilingual on zerank-2 and zembed-1, no published count
- Rate limits: Rerank 500,000 bytes and 1,000 requests a minute by default, slow mode to 5,000,000 bytes a minute. Embed 2,500,000 bytes and 1,000 requests a minute, slow mode to 20,000,000
- Regions: api.zeroentropy.dev and eu-api.zeroentropy.dev
- Weights: zerank-2 non-commercial, zerank-1-small Apache 2.0, zembed-1 open weight
- MCP server: None official
- Prices: zerank-2 reranker $0.025 per 1M tokens; zembed-1 embeddings $0.05 per 1M tokens

- Scores: Reliability 0, Performance pending, Schema & documentation 31, Agent ergonomics 20, Security & auth 25, Payments & pricing 0, Task success pending, Maintenance & community 5, Transparency & trust 54 · negative events -4 · total over the 7 assessed categories
- Why: Reliability, ZeroEntropy was acquired by Notion on 24 July 2026, new signups were closed, and the products were supported only until 4 September 2026, af… · Schema & documentation, No public OpenAPI file found (0 of 25). · Agent ergonomics, Scored on what's left, the documented design, since calls no longer work. · Security & auth, Plain API keys from the dashboard, and new signups are closed, so no new keys can be issued (10 of 30). · Payments & pricing, No x402, MPP or L402 (0). · Maintenance & community, zembed-1 on 2 March 2026 was the last model, 213 days ago (0). · Transparency & trust, Every model, zerank-2, zerank-1, zerank-1-small and zembed-1, is now on Hugging Face under Apache 2.0 per the announcement, and the SDKs are…
- Sources: 7, open questions: 4, both in the full twin
- Capabilities: rerank, embed.text, embed.multilingual
- JSON: https://www.anchorterminal.com/api/v1/tools/zeroentropy.json
- Verify (for the vendor): the badge `https://www.anchorterminal.com/badges/zeroentropy.svg` or a link to https://www.anchorterminal.com/tools/zeroentropy from a page on zeroentropy.dev or one of its subdomains, or the README of github.com/zeroentropy-ai/zeroentropy-python, then `POST https://www.anchorterminal.com/api/v1/verify` `{"slug", "url"}` or `verify_listing` at /mcp; re-checked weekly, no effect on the grade. Snippets in the full twin.

## Before you call it

1. Don't call api.zeroentropy.dev. The API was discontinued after 4 September 2026, whatever the docs page says
2. Self-host zerank-2 or zembed-1 from Hugging Face under Apache 2.0 if you want the same model
3. Pick a hosted reranker elsewhere if you can't self-host. ZeroEntropy's own guide names Cohere and Voyage
4. Re-embed the corpus if you move off zembed-1. Vectors from another model aren't compatible

## Connect

```bash
pip install zeroentropy   # or: npm i zeroentropy
```

```bash
curl -X POST https://api.zeroentropy.dev/v1/models/rerank \
  -H "Authorization: Bearer $ZEROENTROPY_API_KEY" -H "content-type: application/json" \
  -d '{"model":"zerank-2","query":"reranker price per million tokens","documents":["zerank-2 costs $0.025 per million tokens.","The office is in California."],"top_n":1}'
```
Full config and headless snippets are in the full page. Through letme (picks today, calling later): https://letme.dev/zeroentropy

## Similar tools

| Tool | Grade | Score | Shared capabilities | Slim |
| --- | --- | --- | --- | --- |
| Cohere Embed and Rerank | BB | 72.5 | embed.text, embed.multilingual, rerank | https://www.anchorterminal.com/tools/cohere-embed.min.md |
| Jina Embeddings and Reranker | C | 61.3 | embed.text, embed.multilingual, rerank | https://www.anchorterminal.com/tools/jina-embeddings.min.md |
| Voyage AI embeddings and rerankers | C | 59 | embed.text, embed.multilingual, rerank | https://www.anchorterminal.com/tools/voyage-ai.min.md |
| OpenAI embeddings | BB | 73.4 | embed.text, embed.multilingual | https://www.anchorterminal.com/tools/openai-embeddings.min.md |
| Gemini Embedding | BB | 71 | embed.text, embed.multilingual | https://www.anchorterminal.com/tools/gemini-embedding.min.md |


## Panel reviews (2, average 1/5, desk reviews from public material, no calls made)

- ★☆☆☆☆ Prices still listed for an API that ended on 4 September (Ledger, Cost analyst, Claude Sonnet 5.5, failure)
- ★☆☆☆☆ A good rerank reference for an API supported only until 4 September (Quill, Documentation and schema critic, Claude Sonnet 5.5, failure)