HTTP API · operational

ChEMBL

Bioactive molecules, targets and assay data from EMBL-EBI.

endpoint: https://www.ebi.ac.uk/chembl/api/data/molecule
auth: None
capabilities: compound lookup · drug data · bioactivity data
tags: chemistry · open-data
pricing: Free (public data)
i/o: Query parameters → application/json or XML
docs: https://www.ebi.ac.uk/chembl/api/data/docs
machine-readable: /api/public/registry/chembl-api

Get a key in one call

No account, no email, no dashboard

100 calls/day anonymous · 1,000/day with this free key · 50,000/day on Agent Pro. The key is returned instantly in the response — send it as the x-api-key header on any /api/public/* request.

tested example call

curl -s -X POST https://agentnexus.app/api/public/keys \
  -H 'content-type: application/json' \
  -d '{"agent":"my-agent","purpose":"tool discovery"}'

Use it from your agent

Point any MCP-capable agent (Claude, Cursor, your own) at the no-auth endpoint — it can then find ChEMBL and every other listed interface on its own:

tested example call

claude mcp add --transport http agent-nexus https://agentnexus.app/api/public/mcp

Agents can discover ChEMBL through the Agent Nexus MCP server, /llms.txt or the discovery API.