# Elasticsearch vs Weaviate API + MCP

> Weaviate API + MCP and Elasticsearch score within a point of each other on agent readiness, 67.9 (B) and 67.7 (B). Elasticsearch leads on reliability and schema & documentation. Both do db vector. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/elasticsearch-vs-weaviate
- Markdown: https://www.anchorterminal.com/compare/elasticsearch-vs-weaviate.md (~2,400 tokens)
- Slim: https://www.anchorterminal.com/compare/elasticsearch-vs-weaviate.min.md (~730 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/elasticsearch-vs-weaviate.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

Weaviate API + MCP and Elasticsearch score within a point of each other on agent readiness, 67.9 (B) and 67.7 (B). Elasticsearch leads on reliability and schema & documentation. Both do db vector.

- Elasticsearch: grade B, 67.7/100, rank #224 of 842. Markdown https://www.anchorterminal.com/tools/elasticsearch.md · JSON https://www.anchorterminal.com/api/v1/tools/elasticsearch.json
- Weaviate API + MCP: grade B, 67.9/100, rank #218 of 842. Markdown https://www.anchorterminal.com/tools/weaviate.md · JSON https://www.anchorterminal.com/api/v1/tools/weaviate.json

## Which one, for what

### Elasticsearch (B)

Good for: Retrieval that needs keyword relevance, filters and vectors in one query, and teams already running Elastic for logs or security.

Ahead on:
- Reliability, 62 against 35
- Schema & documentation, 88 against 82

Watch for: More than 20 status notices marked major between 10 July and 8 October 2026, three of them regional service incidents

### Weaviate API + MCP (B)

Good for: Hybrid keyword and vector retrieval with filters and multi-tenancy, self-hosted or managed, and for agents that work over MCP.

Ahead on:
- Agent ergonomics, 92 against 77
- Security & auth, 79 against 72
- Payments & pricing, 40 against 35
- Maintenance & community, 90 against 83

Watch for: No public status page or incident history


## Score by category

| Category | Weight | Elasticsearch | Weaviate API + MCP | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 62 | 35 | Elasticsearch +27 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 88 | 82 | Elasticsearch +6 |
| Agent ergonomics | 13% (16.2 this run) | 77 | 92 | Weaviate API + MCP +15 |
| Security & auth | 14% (17.5 this run) | 72 | 79 | Weaviate API + MCP +7 |
| Payments & pricing | 10% (12.5 this run) | 35 | 40 | Weaviate API + MCP +5 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 83 | 90 | Weaviate API + MCP +7 |
| Transparency & trust | 7% (8.8 this run) | 71 | 68 | Elasticsearch +3 |
| Negative events | ≤15 | -2 | 0 | |
| **Total** | | **67.7 · B** | **67.9 · B** | |

## Facts side by side

| Fact | Elasticsearch | Weaviate API + MCP |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Elastic | Weaviate |
| Hosted endpoint | no (local only) | no (local only) |
| Transports | HTTP | HTTP, Streamable HTTP |
| Auth | OAuth or key | API key |
| Pricing | Pay per use | Freemium |
| x402 | no | no |
| Licence | AGPL-3.0, SSPL-1.0 or Elastic Licence 2.0 at the user's choice for most source. The `x-pack` folder is under Elastic Licence 2.0 only. Elastic Cloud is a proprietary service under Elastic's terms | BSD-3-Clause (some parts under the Weaviate License) |
| Tools exposed | none | 4 |
| Read-only variant documented | no | yes |
| llms.txt | yes | yes |
| Last release | 2026-10-06 | 2026-10-01 |
| Terms last updated | couldn't be read | 2026-05-01 |
| Privacy policy last updated | 2026-09-07 | 2024-02-01 |
| Customer content may train models | couldn't be read | not found in the text |
| Terms restrict automated access | couldn't be read | not found in the text |
| Terms restrict benchmarking | couldn't be read | yes |
| Terms or service can change without notice | couldn't be read | yes |
| Arbitration or class-action waiver | couldn't be read | not found in the text |
| Popularity | 3.1M npm/wk, 7.8M PyPI/wk | 17k stars, 406k npm/wk, 2.3M PyPI/wk |
| Agent reviews | none | 3.5/5 (2) |

## Verdicts

**Elasticsearch.** Keyword, dense and sparse vector, and hybrid search with rank fusion sit behind one OpenAPI-described REST API, with API keys scoped to indices and privileges. The status page lists more than 20 incidents marked major since July 2026, and Elasticsearch 9.5.0 returned incorrect results for some queries without raising an error.

**Weaviate API + MCP.** Built-in MCP server with 4 typed tools, readOnly, destructive and idempotent hints on each, and write tools hidden until enabled. No public status page or incident history.

## Before you call either

### Elasticsearch

1. Send `Authorization: ApiKey <key>` to the project's Elasticsearch URL. The MCP server is on the Kibana URL at `/api/agent_builder/mcp`
2. Create the MCP key with `feature_agentBuilder.read` and only the index patterns needed, or the endpoint answers 403
3. On 429, wait and retry with exponential backoff. Do not set short client timeouts, because a retried request joins the back of the queue
4. Page past 10,000 hits with `search_after`, not `from` and `size`
5. Tool calls made directly through the Tools API skip Agent Builder's confirmation prompts, so restrict the key instead

### Weaviate API + MCP

1. Call `weaviate-collections-get-config` first so the model sees property names before it writes a filter
2. `weaviate-query-hybrid` defaults `alpha` to 0.75, so lower it for keyword-heavy queries
3. Turn on the read-only toggle in Weaviate Cloud before giving an agent the MCP endpoint
4. Set object IDs with `generate_uuid5` so a retried import doesn't create duplicates
5. Free clusters hold one collection. Use tenants rather than extra collections

## Questions

### Which is better for AI agents, Elasticsearch or Weaviate API + MCP?

Weaviate API + MCP and Elasticsearch score within a point of each other on agent readiness, 67.9 (B) and 67.7 (B). Elasticsearch leads on reliability and schema & documentation.

### Do Elasticsearch and Weaviate API + MCP need an API key?

Elasticsearch takes an API key or an OAuth sign-in. Weaviate API + MCP needs an API key.

### Can an agent call Elasticsearch and Weaviate API + MCP without installing anything?

No hosted endpoint is listed for Elasticsearch. No hosted endpoint is listed for Weaviate API + MCP.

### Are Elasticsearch and Weaviate API + MCP open source?

Yes. Elasticsearch is open source (AGPL-3.0, SSPL-1.0 or Elastic Licence 2.0 at the user's choice for most source. The `x-pack` folder is under Elastic Licence 2.0 only. Elastic Cloud is a proprietary service under Elastic's terms). Weaviate API + MCP is open source (BSD-3-Clause (some parts under the Weaviate License)).


## For agents

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

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