City of Chicago

Open Data IL Live

Query public building permit status for City of Chicago via the SignedOff API.

Quick Start

# Look up a City of Chicago permit
curl -H "X-API-Key: YOUR_KEY" \
"https://signedoff.io/api/v1/permits/B200481960/status?jurisdiction=chicago"

Include jurisdiction=chicago because Chicago B-number formats overlap permit formats used by other supported cities.

Sample Response

{
"permit_number": "B200481960",
"status": "ACTIVE",
"jurisdiction": "City of Chicago",
"platform": "socrata",
"data_freshness": {
"cached": true,
"last_refreshed": "2026-05-07T08:00:00Z",
"cache_ttl_seconds": 14400
}
}

Integration Notes

  • Chicago coverage comes from the official issued-permits dataset. It can return published status, milestone, dates, and permit condition fields, but it is not a complete application or inspection workflow.
  • Permit data is cached for 4 hours. The data_freshness object in every response shows when the data was last fetched from the portal.
  • Pro and Enterprise plans can use force_refresh=true to bypass the cache and fetch live data.

The SignedOff API provides programmatic access to City of Chicago building permit data from its official public source. Developers receive structured issued-permit status, milestone, and other fields published by the Chicago Data Portal without repeating manual lookups. Available fields remain source-specific, and the official jurisdiction record is authoritative.

Jurisdiction API FAQ

City of Chicago permit API questions

How do I check City of Chicago permit status by API?

Send the exact permit number with jurisdiction=chicago. The response includes the issued permit's published status, milestone, available dates, and data-freshness details. It does not claim a complete pre-issuance or inspection history.

What permit number format does City of Chicago use?

A representative City of Chicago permit number is B200481960. Permit formats can vary by record type and issue year, so applications should preserve letters, digits, and separators exactly as issued.

How fresh is City of Chicago permit data?

SignedOff caches permit responses for up to four hours and reports the last refresh time in every response. Pro and Enterprise requests can use force_refresh=true when an immediate portal check is needed.

Does the City of Chicago Permit API require a jurisdiction parameter?

Yes. Include jurisdiction=chicago because the City's B-number pattern overlaps formats used by other supported jurisdictions.

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