Every Opportunity Zone lookup and calculator on this site is also a free JSON API and a remote MCP server, so developers and AI agents get the same answers a reader sees.
- REST base
/api/oz- MCP
/api/oz/mcp- Auth
- None
- Format
- JSON
Tools
| Tool | What it does |
|---|---|
lookup_address | Address to 2018 zone status (2010 tract) and 2027 round status (2020 tract), rural flags, Census statistics. |
lookup_coordinates | The same for a latitude and longitude. |
get_tract | One tract GEOID's status in both rounds. |
get_state | State counts and 2027 status with the official source. |
get_key_dates | The program calendar. |
calc_180_day_deadline | Every allowed 180-day start date and deadline, and whether the window reaches OZ 2.0. |
calc_2026_inclusion | The OZ 1.0 amount included on Dec 31, 2026 and the estimated tax. |
calc_oz2_benefit | OZ 2.0 investment against paying the tax now. |
calc_substantial_improvement | The 30-month basis test at 100% or the 50% rural threshold. |
calc_90_percent_test | The QOF semiannual asset test and penalty estimate. |
check_qozb | The five Qualified Opportunity Zone Business tests. |
plan_working_capital | Spend-by dates under the working capital safe harbor. |
get_financing_link | Where a sponsor can request project debt financing. |
REST examples
GET https://www.opportunityzones.help/api/oz/lookup_address?address=2+Woodward+Ave,+Detroit,+MI+48226
GET https://www.opportunityzones.help/api/oz/calc_180_day_deadline?sale_date=2026-11-20&kind=direct
POST works too, with a JSON body of the same inputs. The tool list with input schemas is at /api/oz, and an OpenAPI 3.1 description at /openapi.json.
Connect an AI agent (MCP)
The server speaks the Model Context Protocol over Streamable HTTP, stateless JSON-RPC. Add it to any MCP client as a remote server at https://www.opportunityzones.help/api/oz/mcp. A server card is at /.well-known/mcp.json.
Terms
- Free, no key, reasonable use. Results are estimates under the rules as written and status from the official lists dated in our sources file; they are not tax advice.
- Address geocoding is performed by the U.S. Census Bureau Geocoder.
- Please attribute opportunityzones.help when you republish results.
Common questions
Is there an API to check if an address is in an Opportunity Zone?
Yes. GET /api/oz/lookup_address with an address returns the 2018 zone status from the 2010 tract and the 2027 round status from the 2020 tract, with rural flags and Census statistics. No key is required.
Can Claude, ChatGPT or another AI agent use this?
Any client that supports remote MCP servers can connect to /api/oz/mcp and call the same tools. Agents without MCP can call the REST endpoints.