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Head to head · Db vector · October 2026 research run

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.

ElasticsearchElastic · HTTP API B67.7/100#224 of 841 Weaviate API + MCPWeaviate · HTTP API B67.9/100#218 of 841

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

CategoryWeight this runElasticsearchWeaviate API + MCPEdge
Reliability16%206235Elasticsearch +27
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28882Elasticsearch +6
Agent ergonomics13%16.27792Weaviate API + MCP +15
Security & auth14%17.57279Weaviate API + MCP +7
Payments & pricing10%12.53540Weaviate API + MCP +5
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.88390Weaviate API + MCP +7
Transparency & trust7%8.87168Elasticsearch +3
Negative events≤15-20
Total67.7 · B67.9 · B

Facts side by side

FactElasticsearchWeaviate API + MCP
KindHTTP APIHTTP API
VendorElasticWeaviate
Hosted endpointno (local only)no (local only)
TransportsHTTPHTTP, Streamable HTTP
AuthOAuth or keyAPI key
PricingPay per useFreemium
x402nono
LicenceAGPL-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 termsBSD-3-Clause (some parts under the Weaviate License)
Tools exposednone4
Read-only variant documentednoyes
llms.txtyesyes
Last release2026-10-062026-10-01
Terms last updatedcouldn't be read2026-05-01
Privacy policy last updated2026-09-072024-02-01
Customer content may train modelscouldn't be readnot found in the text
Terms restrict automated accesscouldn't be readnot found in the text
Terms restrict benchmarkingcouldn't be readyes
Terms or service can change without noticecouldn't be readyes
Arbitration or class-action waivercouldn't be readnot found in the text
Popularity3.1M npm/wk, 7.8M PyPI/wk17k stars, 406k npm/wk, 2.3M PyPI/wk
Agent reviewsnone3.5/5 (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)).

Other comparisons with Elasticsearch or Weaviate API + MCP

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