Developers

Cost Estimate API

The free tier is live: 100 requests/month, key issued instantly by email, no signup. The API returns website, ecommerce, app, and MVP cost estimates as JSON — the same 9-engine calculation pipeline behind the free calculator, calibrated against 600+ project quotes and public rate benchmarks.

Weighing building your own estimation engine instead? Read the build-vs-buy cost breakdown →

The public dataset behind the API needs no key: /api/cost-data (JSON) and /rates-2026.csv, both CC BY 4.0. Cite as: Project Cost Estimator, “Website Cost Dataset 2026”, projectcostestimator.com/api/cost-data (CC BY 4.0). Browsable versions: Cost Index and Rate Database.

Get your free API key

Enter your email — the key appears here instantly and lands in your inbox. 100 requests/month, free.

Live endpoints

POST/api/v1/estimateLiveBearer key (free)

Generate a full project cost estimate from any subset of the calculator’s fields

Response: { totalCost, currency, platform, timelineWeeks, monthlyCost, complexity, riskLevel, confidence, costBreakdown, meta }

GET/api/cost-dataLiveNone — open

The full open dataset behind the engine: platform, market, and tier multipliers + medians (CC BY 4.0). No key, no rate limit — built for citation.

Response: Dataset-shaped JSON

Coming soon

POST/api/v1/compareNot live yet

Compare estimates across multiple platforms in one call

GET/api/v1/cost-indexNot live yet

Market rate data by project type and region

Quick example

Send any subset of the calculator's fields (for example projectType, market, pricingTier, designType, numberOfPages, numberOfProducts, forcePlatform) — anything you leave out uses the calculator's defaults. All amounts are USD.

curl -X POST https://projectcostestimator.com/api/v1/estimate \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "projectType": "ecommerce",
    "market": "us",
    "pricingTier": "freelancer",
    "forcePlatform": "shopify"
  }'
{
  "totalCost": 6000,
  "currency": "USD",
  "platform": "shopify",
  "platformLabel": "Shopify",
  "timelineWeeks": 3,
  "monthlyCost": 81.5,
  "complexity": 30,
  "complexityLevel": "Low",
  "riskLevel": "Low",
  "riskScore": 17,
  "confidence": { "score": 54, "level": "Medium", "missingDetails": [], "message": "..." },
  "costBreakdown": {
    "basePrice": 5565,
    "featureAdditions": 0,
    "developmentCost": 5843,
    "contingency": 278,
    "totalHours": 53,
    "hourlyRate": 105
  },
  "input": {
    "applied": { "projectType": "ecommerce", "market": "us", "pricingTier": "freelancer", "forcePlatform": "shopify" },
    "ignored": [],
    "defaultsFor": ["projectOrigin", "numberOfPages", "..."]
  },
  "meta": {
    "engine": "9-engine v2026",
    "calibration": "600+ project quotes and public rate benchmarks",
    "docs": "https://projectcostestimator.com/api-docs"
  }
}

Missing or invalid key → 401. Free-tier quota is 100 requests per calendar month per key, plus a burst limit of 10 requests then one every 2 seconds (429 with Retry-After). Body limit 32 KB.

Fields, aliases and errors

  • The key goes in Authorization: Bearer pce_... or in X-API-Key: pce_.... Never in the URL.
  • GET /api/v1/estimate?projectType=ecommerce&market=us&numberOfProducts=120 returns the same estimate as the POST; nested fields use a dot (contentCreation.video=stock_clips).
  • Every field and its allowed values are in the OpenAPI document at /.well-known/openapi.json; the response's input.applied and input.ignored say what the engine used.
  • Common names are accepted as aliases: platform → forcePlatform, location/region/country → market, tier → pricingTier, pages/products → the count bands. Values match case-insensitively (USA, Magento, shop all resolve); booleans map to yes/no; a bare number of pages or products is banded.
  • A value outside a field's allowed set returns 400 with invalid: [{ field, given, allowed }] and the full field reference, so a client can correct itself without reading the docs.

API pricing

Free

Live now

$0

100 requests/month

  • ✔ Full estimate endpoint (all calculator fields)
  • ✔ Key by email, instant, no signup
  • ✔ Open dataset endpoint, no key needed
Get your key ↑

Paid tiers

Coming soon

Higher quotas + extra endpoints

We only sell what exists. Paid tiers ship after the compare and cost-index endpoints do. Need more than 100 requests/month today? Reply to your key email and tell us your use case.