research by fourzerotwo

Journal by ISSN

Journal title, publisher and DOI counts by ISSN.

Journal by ISSN Free

Journal title, publisher and DOI counts by ISSN.

cost: Free then $0.002 / call
MCP tool: crossref__journal
method: GET

Free up to 50 calls a day over MCP (500 with a free key), then $0.002 per call by card credit or USDC. Free key · Pay by card

GET https://fourzerotwo.si/v1/crossref/journal

Param	Type	Description
issn	string	ISSN

# free: send a free key from https://fourzerotwo.si/free
curl -H "X-API-Key: fzt_…" "https://fourzerotwo.si/v1/crossref/journal?issn=0028-0836"

# no key: returns 402 with the price, for x402 agents
curl -i "https://fourzerotwo.si/v1/crossref/journal?issn=0028-0836"

by fourzerotwo

Report this endpoint

Use it from an AI agent (MCP)

Add the server once, then ask for this data in plain English. The agent finds the endpoint with search_apis and runs it with call_api.

{
  "mcpServers": {
    "fourzerotwo": { "type": "http", "url": "https://fourzerotwo.si/mcp" }
  }
}

# the call the agent makes
call_api {"tool": "crossref__journal", "arguments": {"issn":"0028-0836"}}

Journal by ISSN

Journal by ISSN Free

Use it from an AI agent (MCP)

More from Crossref DOI Metadata