# Meilisearch vs OpenSearch

> Meilisearch scores 78.6 (A) to OpenSearch's 68 (B) for vector search. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/meilisearch-vs-opensearch
- Markdown: https://www.anchorterminal.com/compare/meilisearch-vs-opensearch.md (~2,600 tokens)
- Slim: https://www.anchorterminal.com/compare/meilisearch-vs-opensearch.min.md (~730 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/meilisearch-vs-opensearch.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-09

Meilisearch scores 78.6 (A) on agent readiness against OpenSearch's 68 (B), and leads in 5 of 7 scored categories. OpenSearch leads on payments & pricing. Both do vector search.

- Meilisearch: grade A, 78.6/100, rank #14 of 950. Markdown https://www.anchorterminal.com/tools/meilisearch.md · JSON https://www.anchorterminal.com/api/v1/tools/meilisearch.json
- OpenSearch: grade B, 68/100, rank #233 of 950. Markdown https://www.anchorterminal.com/tools/opensearch.md · JSON https://www.anchorterminal.com/api/v1/tools/opensearch.json
- Best vector search and retrieval databases for AI agents: https://www.anchorterminal.com/best/vector-search/index.md
- All 85 retrieval comparisons: https://www.anchorterminal.com/compare/vector-search/index.md

## Which one, for what

### Meilisearch (A)

Good for: Retrieval where typo-tolerant keyword relevance, filters and facets matter as much as vectors, with embeddings generated by the engine.

Ahead on:
- Reliability, 90 against 77
- Schema & documentation, 93 against 77
- Agent ergonomics, 87 against 80
- Maintenance & community, 93 against 84
- Transparency & trust, 74 against 57

Also in its favour:
- Agent-ready, a grade of BB or better
- Free to start without a card
- No incidents deducted, where OpenSearch loses 5 points for them

Watch for: The `/mcp` route is an experimental feature that must be switched on, and its four tools carry no read-only annotations

### OpenSearch (B)

Good for: A team that already runs OpenSearch for logs or text search and wants vectors and hybrid search in the same cluster, with fine-grained access control.

Ahead on:
- Payments & pricing, 60 against 40

Also in its favour:
- Runs on your own machine

Watch for: No hosted service from the foundation. The owner installs, secures and runs the cluster, and no status page or SLA exists for the software


## Score by category

| Category | Weight | Meilisearch | OpenSearch | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 90 | 77 | Meilisearch +13 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 93 | 77 | Meilisearch +16 |
| Agent ergonomics | 13% (16.2 this run) | 87 | 80 | Meilisearch +7 |
| Security & auth | 14% (17.5 this run) | 67 | 70 | OpenSearch +3 |
| Payments & pricing | 10% (12.5 this run) | 40 | 60 | OpenSearch +20 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 93 | 84 | Meilisearch +9 |
| Transparency & trust | 7% (8.8 this run) | 74 | 57 | Meilisearch +17 |
| Negative events | ≤15 | 0 | -5 | |
| **Total** | | **78.6 · A** | **68 · B** | |

## Facts side by side

| Fact | Meilisearch | OpenSearch |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Meilisearch | OpenSearch Software Foundation |
| Hosted endpoint | no (local only) | no (local only) |
| Transports | HTTP | HTTP, stdio |
| Auth | API key | OAuth or key |
| Pricing | Pay per use | Free |
| x402 | no | no |
| Licence | MIT for the Community Edition. Enterprise Edition code, which powers Meilisearch Cloud, is BUSL-1.1 | Apache-2.0 for the engine, the plugins, the clients, the API specification and the MCP server |
| Tools exposed | 4 | 9 |
| Read-only variant documented | no | no |
| llms.txt | yes | no |
| Last release | 2026-10-01 | 2026-09-22 |
| Terms last updated | no date given | no document linked |
| Privacy policy last updated | 2025-03-17 | no document linked |
| Customer content may train models | not found in the text |  |
| Terms restrict automated access | not found in the text |  |
| Terms restrict benchmarking | yes |  |
| Terms or service can change without notice | not found in the text |  |
| Arbitration or class-action waiver | not found in the text |  |
| Popularity | 60k stars, 752k npm/wk | 14k stars |

## Verdicts

**Meilisearch.** Keyword, vector and hybrid search share one request, behind keys scoped by action and index and a published OpenAPI 3.1 file with 143 operations. The built-in MCP server is experimental and read-only, and Cloud access starts with a browser sign-up and a 14-day trial.

**OpenSearch.** OpenSearch 3.9.0 runs vector, text and hybrid search under Apache-2.0, with an OpenAPI 3.1 description of its REST API and API keys limited by permission and index pattern. The owner runs the cluster, no status page or SLA comes with the software, and no tool in the MCP server sets a read-only or destructive annotation.

## Before you call either

### Meilisearch

1. Create a key with only `search`, `documents.get` and `indexes.get` on the indexes needed. The default search key fails `listIndexes` and `describeIndex` over MCP
2. Enable the `mcpRoute` experimental feature first. Until then `/mcp` answers `feature_not_enabled`
3. For hybrid search send `hybrid` with an `embedder` name configured in the index settings and a `semanticRatio` from 0 to 1
4. Writes return a `taskUid` and run asynchronously. Poll the task before searching for the new documents
5. On 503 `too_many_search_requests`, wait for the `Retry-After` header (10 seconds) before retrying

### OpenSearch

1. Create the index with `index.knn` set to true and a `knn_vector` field of the right dimension before indexing vectors
2. Put the `filter` clause inside the `knn` query for filtering during the search. A filter outside it runs afterwards and can return fewer than `k` hits
3. Ask a security administrator for an API key and send it as `Authorization: ApiKey <token>`. The token is shown once and lasts 90 days at most
4. Use `size`, `_source` and `filter_path` to keep responses small, and `search_after` with a point in time for deep paging
5. Set `OPENSEARCH_SETTINGS_ALLOW_WRITE=false` on the MCP server unless writes are needed. `GenericOpenSearchApiTool` can call any endpoint

## Questions

### Which is better for AI agents, Meilisearch or OpenSearch?

Meilisearch scores 78.6 (A) on agent readiness against OpenSearch's 68 (B), and leads in 5 of 7 scored categories. OpenSearch leads on payments & pricing.

### Do Meilisearch and OpenSearch need an API key?

Meilisearch needs an API key. OpenSearch takes an API key or an OAuth sign-in.

### Can an agent call Meilisearch and OpenSearch without installing anything?

No hosted endpoint is listed for Meilisearch. OpenSearch runs on your own machine, with no hosted endpoint listed.

### Are Meilisearch and OpenSearch open source?

Yes. Meilisearch is open source (MIT for the Community Edition. Enterprise Edition code, which powers Meilisearch Cloud, is BUSL-1.1). OpenSearch is open source (Apache-2.0 for the engine, the plugins, the clients, the API specification and the MCP server).


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/meilisearch-vs-opensearch.json, and with the fewest tokens: https://www.anchorterminal.com/compare/meilisearch-vs-opensearch.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "meilisearch", "b": "opensearch"}`. From a terminal: `anchor compare meilisearch opensearch`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/meilisearch.json and https://www.anchorterminal.com/api/v1/tools/opensearch.json

## Other comparisons with Meilisearch or OpenSearch

- [Chroma API + MCP vs Meilisearch](https://www.anchorterminal.com/compare/chroma-vs-meilisearch.md)
- [Chroma API + MCP vs OpenSearch](https://www.anchorterminal.com/compare/chroma-vs-opensearch.md)
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- [Meilisearch vs Milvus and Zilliz Cloud API + MCP](https://www.anchorterminal.com/compare/meilisearch-vs-milvus-zilliz.md)
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- [Meilisearch vs Vespa](https://www.anchorterminal.com/compare/meilisearch-vs-vespa.md)
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- [Milvus and Zilliz Cloud API + MCP vs OpenSearch](https://www.anchorterminal.com/compare/milvus-zilliz-vs-opensearch.md)
- [OpenSearch vs Pinecone API + MCP](https://www.anchorterminal.com/compare/opensearch-vs-pinecone.md)
- [OpenSearch vs Qdrant API + MCP](https://www.anchorterminal.com/compare/opensearch-vs-qdrant.md)
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- [OpenSearch vs Upstash Vector API + MCP](https://www.anchorterminal.com/compare/opensearch-vs-upstash-vector.md)
- [OpenSearch vs Vespa](https://www.anchorterminal.com/compare/opensearch-vs-vespa.md)
- [OpenSearch vs Weaviate API + MCP](https://www.anchorterminal.com/compare/opensearch-vs-weaviate.md)