Endpoint design

The endpoint surface is finalised. These are the routes the hosted API will expose when it goes self-serve. Until then, the same data is available on request via tailored delivery — email us with what you need.

Full OpenAPI spec available at launch. Response format: JSON. Error responses follow RFC 7807 problem-details.

Example requests and responses

Illustrative examples of what the API will return when self-serve. While in manual onboarding, the same response shape is provided as JSON files on request.

Look up a Universal Beam

GET https://api.steelspec.io/v1/sections/UB/305x165x40

Response:
{
  "designation": "305x165x40",
  "serialSize": "305x165",
  "massPerMetre": 40.3,
  "depthOfSection": 303.4,
  "widthOfSection": 165,
  "webThickness": 6.0,
  "flangeThickness": 10.2,
  "secondMomentOfAreaX": 8503,
  "secondMomentOfAreaY": 764,
  "elasticModulusX": 561,
  "plasticModulusX": 623,
  "areaOfSection": 51.3,
  "_source": {
    "sourceDoc": "tata-blue-book-2023",
    "verified": true,
    "verifiedDate": "2026-03-23"
  }
}

Estimate embodied carbon

POST https://api.steelspec.io/v1/embodied-carbon/estimate
Content-Type: application/json

{
  "mass_kg": 50000,
  "route": "eaf-scrap-renewable",
  "modules": ["A1", "A2", "A3", "A4", "A5"]
}

Response:
{
  "mass_kg": 50000,
  "route": "eaf-scrap-renewable",
  "routeLabel": "100% scrap-based EAF with renewable energy (Xcarb)",
  "modules": {
    "A1": 16500.0,
    "A2": 1200.0,
    "A3": 4500.0,
    "A4": 650.0,
    "A5": 1000.0
  },
  "totalKgCO2e": 23850.0
}

Filter purlins by manufacturer

GET https://api.steelspec.io/v1/purlins/Z?manufacturer=Steadmans&depth_mm=200

Response: list of all Steadmans Z purlins with depth ≈ 200mm,
each with full section properties.

Intended pricing model

This is the tier structure planned for self-serve launch. While in manual onboarding, individual access arrangements are no charge for engineers and AI tooling builders — email us with your use case and we'll set you up.

Free tier will be permanent — UK structural steel reference data should not be locked behind a paywall for engineers and educators.

What's built

• Built 876 hot-rolled sections (UB, UC, PFC, EA, UA, CHS, SHS, RHS, Tees) — verified, with full geometric + mechanical properties
• Built 689 cold-formed sections (Z purlins, C purlins) across 9 UK manufacturers
• Built Connection design rules (Eurocode 3-1-8) — bolt capacities, spacings, block shear, plate bearing, weld design
• Built Embodied carbon factors (SCI P449) — five production routes, full life-cycle modules
• Built Material grades (BS EN 10025), plate data, fixings, cladding profiles, rooflights
• Manual onboarding Data delivery on request — email us for the slice you need

On the roadmap

• Roadmap Self-serve hosted REST API — deploys when there's enough demand to justify the hosting
• Roadmap Hosted MCP server with SSE transport — see MCP page
• Roadmap IFC BOM extractor — upload an IFC file, get a categorised structured BOM with embodied carbon totals
• Roadmap Component design agent — minimum-material plate sizing for cleats, fin plates, gussets
• Roadmap Per-material procurement agents — bolts first, then cladding, fixings