Site build cost
GET /v1/site/build-costBuild cost for a scheme: the sector's cost index with its 1- and 5-year movement, the regional location factor (`region`: NATIONAL, LONDON, SOUTH_EAST — an error lists what is loaded), the editorial on-cost percentages (prelims, contingency, overheads & profit, professional fees) and, given `gia_m2` and `rate_gbp_m2` (your BCIS or in-house base rate, with `rate_period` in the series' own format, e.g. 2024Q1), an estimate: the rate carried through the index to the latest period, localised, multiplied out, with totals at low / mid / high on-costs. The £/m² benchmark leg says `not_available` until a tender benchmark is loaded — no rate is invented, and nothing here is a modelled number. UK only.
Same call over MCP
Build cost: index, regional factor, estimatebuild_costAuthenticate with an API key from the API & MCP Hub. The same call is available as an MCP tool at the same price.
Inputs
Before you call it
- sector
- Sectors follow the VOA classification (OFFICE, RETAIL, INDUSTRIAL_WAREHOUSE, HOTEL and so on). Omit the argument for all sectors; the response names the sectors published for an area when the one you asked for is not.
Request
Calling GET /v1/site/build-cost
curl "https://api.marketcode.ai/v1/site/build-cost?sector=%3Csector%3E" \
-H "Authorization: Bearer $MARKETCODE_API_KEY"Send your API key as a Bearer token. Every response carries credits_charged and credits_remaining.
Inputs
Parameters
| Name | In | Type | Required | Description |
|---|---|---|---|---|
| sector | Query | string | Yes | residential | commercial | industrial | infrastructure | public | all |
| region | Query | string | No | Location-factor region key: NATIONAL, LONDON, SOUTH_EAST (a 422 lists what is loaded)Default: NATIONAL |
| gia_m2 | Query | number | No | Gross internal area, m² |
| basis | Query | string | No | tender | outputDefault: tender |
| rate_gbp_m2 | Query | number | No | Your base build rate £/m²; required for an estimate while no benchmark is loaded |
| rate_period | Query | string | No | Period that rate is priced at, in the series' own format (2024Q1 / 2024M01) |
Price and licence
What it costs, and where the data comes from
Site build cost is free over MCP and over REST, and the two surfaces share one credit balance. Free calls need a signed-in account or an API key and appear in your usage, but they never touch your balance.
Credits are granted on sign-up and bought in packs; the pricing page lists every call.
Related
Endpoints used with Site build cost
- Construction cost index seriesFree
cost_indexConstruction cost index series for a development appraisal's cost side: `basis` is tender (tender price indices), output (output price indices), deflator (the construction deflator) or labour. Optional `sector` (residential, commercial, industrial, infrastructure, all, …), `freq` (monthly | quarterly | annual) and an inclusive period window in the series' own format (2014Q1, 2014M01, 2014). Each series carries its base period and method. UK-wide; regional factors come with the site appraisal. UK only.Same category - Adjacent parcels, owners and the combined site2 credits
land_assemblyThe parcels adjacent to one parcel and who owns each — the first question of a site assembly. Returns each neighbour with its area, land use, constraints and registered proprietor, plus a `combined` block: total area in m² and hectares, the number of distinct owners, how many neighbours already share the subject's proprietor (the parcels needing no second negotiation), how many have no linked owner, and every constraint present across the whole assembly.Same category - One parcel: owner, units, plot, constraints1 credit
parcel_lookupOne land parcel in full: its INSPIRE id, title number and OS id, area and land use, the registered proprietor where a title links, the units standing on it, plot utilisation, and every constraint flag.Same category - Site appraisal dossier5 credits
site_appraisalEverything known about ONE site, assembled and judged — the site dossier.Same category - Rated commercial stock in an authority2 credits
sourcing_commercialRated commercial stock in a local authority, filtered by sector and rateable value — the commercial sourcing lane. Each row carries its rateable value, an income-basis value, the freeholder where a title links, and any auction history.Same category - Live listings enriched against our valuation2 credits
sourcing_live_listingsWhat is on the market RIGHT NOW in these postcode districts, each listing enriched against our own record of the property: asking price against our valuation (`asking_vs_avm_pct`, `discount_to_avm_gbp`), £/m², gross yield on both the asking and valuation bases, unexpired lease years, EPC with its retrofit gap, the designation flags, days listed, the agent, and a plain-language `signals` list.Same category
FAQ
Questions about Site build cost
How much does `build_cost` cost?
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Site build cost is free over MCP and over REST, and the two surfaces share one credit balance. Free calls need a signed-in account or an API key and appear in your usage, but they never touch your balance.
How do I authenticate?
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Send your API key as a Bearer token in the Authorization header. Keys are created in the API & MCP Hub, shown once and revocable. Every response carries the credits charged and your remaining balance.
Is there an MCP version?
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Yes. The build_cost tool on the MarketCode MCP server is the same call at the same price, signed in with OAuth rather than a key, so Claude, ChatGPT, Codex and Cursor can run it in a conversation.
Where does the data come from?
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The answer is computed by MarketCode. Coverage is the UK.
Does `build_cost` change anything?
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No. The tool is annotated read-only on the server, so it never writes to your data or ours and an assistant can call it without a confirmation step.
Try Site build cost on a real address.
30-minute call. We'll provision a key and walk through the endpoint on your use case.