API Documentation

Everything you need to detect website tech stacks programmatically.

Base URL

https://stackpeek.web.app

All API endpoints are under /api/v1/.

Authentication

The free tier (GET /api/v1/detect) requires no authentication and is rate limited. For higher limits and batch scanning, include your API key in the x-api-key header:

curl -H "x-api-key: stk_your_key_here" ...

API keys use the stk_ prefix. You can generate one for free via the /api/v1/keys endpoint.

Detect Tech Stack (Free Tier)

Scan a single URL and return all detected technologies with confidence scores. The URL is automatically prefixed with https:// if no protocol is provided.

Query Parameters

curl "https://stackpeek.web.app/api/v1/detect?url=stripe.com"

const res = await fetch(
  "https://stackpeek.web.app/api/v1/detect?url=stripe.com"
);
const data = await res.json();
console.log(data.technologies);

import requests

resp = requests.get(
    "https://stackpeek.web.app/api/v1/detect",
    params={"url": "stripe.com"}
)
data = resp.json()
print(data["technologies"])

Example Response

{
  "url": "https://stripe.com/",
  "technologies": [
    { "name": "React", "category": "Frontend Framework", "confidence": 95 },
    { "name": "Next.js", "category": "Frontend Framework", "confidence": 90 },
    { "name": "Cloudflare", "category": "CDN", "confidence": 100 },
    { "name": "Stripe", "category": "Payments", "confidence": 100 }
  ],
  "categories": {
    "Frontend Framework": [
      { "name": "React", "confidence": 95 },
      { "name": "Next.js", "confidence": 90 }
    ],
    "CDN": [{ "name": "Cloudflare", "confidence": 100 }],
    "Payments": [{ "name": "Stripe", "confidence": 100 }]
  },
  "meta": {
    "technologiesDetected": 4,
    "scanDuration": "342ms",
    "timestamp": "2026-03-28T12:00:00.000Z"
  }
}

Batch Detection (Paid Tier)

Scan up to 10 URLs in a single request. Each URL is scanned concurrently. Requires an API key on a Starter or Pro plan.

Request Body

curl -X POST "https://stackpeek.web.app/api/v1/detect/batch" \
  -H "x-api-key: stk_your_key_here" \
  -H "Content-Type: application/json" \
  -d '{
    "urls": [
      "https://stripe.com",
      "https://vercel.com",
      "https://linear.app"
    ]
  }'

const res = await fetch("https://stackpeek.web.app/api/v1/detect/batch", {
  method: "POST",
  headers: {
    "x-api-key": "stk_your_key_here",
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    urls: ["https://stripe.com", "https://vercel.com"]
  }),
});
const data = await res.json();
console.log(data.results);

import requests

resp = requests.post(
    "https://stackpeek.web.app/api/v1/detect/batch",
    headers={"x-api-key": "stk_your_key_here"},
    json={"urls": ["https://stripe.com", "https://vercel.com"]}
)
for result in resp.json()["results"]:
    print(result["url"], len(result["technologies"]), "techs")

Example Response

{
  "results": [
    {
      "url": "https://stripe.com/",
      "technologies": [/* ... */],
      "status": "ok"
    },
    {
      "url": "https://vercel.com/",
      "technologies": [/* ... */],
      "status": "ok"
    }
  ],
  "meta": {
    "total": 2,
    "timestamp": "2026-03-28T12:00:00.000Z"
  }
}

Get an API Key

Create a free API key. You start on the free plan with 100 scans/day.

curl -X POST "https://stackpeek.web.app/api/v1/keys" \
  -H "Content-Type: application/json" \
  -d '{"email": "you@example.com"}'

const res = await fetch("https://stackpeek.web.app/api/v1/keys", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({ email: "you@example.com" }),
});
const { apiKey } = await res.json();
console.log("Your key:", apiKey);

import requests

resp = requests.post(
    "https://stackpeek.web.app/api/v1/keys",
    json={"email": "you@example.com"}
)
print(resp.json()["apiKey"])

Response

{
  "apiKey": "stk_abc123def456...",
  "plan": "free",
  "limit": "100 scans/day"
}

Check Usage

Check your current usage stats and plan details.

curl -H "x-api-key: stk_your_key_here" \
  "https://stackpeek.web.app/api/v1/usage"

Response

{
  "plan": "starter",
  "requestsToday": 142,
  "requestsThisMonth": 3847
}

Health Check

Check if the API is up and running. Useful for monitoring and uptime checks.

curl "https://stackpeek.web.app/api/health"

Response

{
  "status": "ok",
  "service": "stackpeek",
  "version": "1.0.0"
}

Response Format

Every detection response includes three sections:

technologies

A flat array of all detected technologies. Each item contains:

categories

The same technologies grouped by category. Each key is a category name, and the value is an array of { name, confidence } objects.

meta

Rate Limits

Rate limits reset daily at midnight UTC and monthly on the 1st. The free GET endpoint also has a per-IP rate limit to prevent abuse. If you exceed your limit, the API returns a 429 response.

Timeouts: Target URLs that don't respond within 10 seconds are aborted with a 504 response. Private/internal URLs (localhost, 127.0.0.1, 10.x, 192.168.x) are blocked.

Pricing

Upgrade anytime at stackpeek.web.app/#pricing. All paid plans include a 7-day free trial.

Error Codes

Error responses return JSON:

{
  "error": "Missing required parameter: url",
  "example": "/api/v1/detect?url=https://example.com"
}

Full Examples

Scan a site and list all frameworks

async function getFrameworks(url) {
  const res = await fetch(
    `https://stackpeek.web.app/api/v1/detect?url=${url}`
  );
  const { categories } = await res.json();

  const frameworks = categories["Frontend Framework"] || [];
  frameworks.forEach(fw =>
    console.log(`${fw.name} (${fw.confidence}% confidence)`)
  );
}

getFrameworks("vercel.com");

import requests

def get_frameworks(url):
    resp = requests.get(
        "https://stackpeek.web.app/api/v1/detect",
        params={"url": url}
    )
    categories = resp.json()["categories"]

    for fw in categories.get("Frontend Framework", []):
        print(f"{fw['name']} ({fw['confidence']}% confidence)")

get_frameworks("vercel.com")

Batch scan competitors

const API_KEY = "stk_your_key_here";

const res = await fetch("https://stackpeek.web.app/api/v1/detect/batch", {
  method: "POST",
  headers: {
    "x-api-key": API_KEY,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    urls: [
      "https://competitor1.com",
      "https://competitor2.com",
      "https://competitor3.com",
    ],
  }),
});

const { results } = await res.json();
results.forEach(r => {
  console.log(`\n${r.url}:`);
  r.technologies.forEach(t =>
    console.log(`  ${t.category}: ${t.name}`)
  );
});

import requests

API_KEY = "stk_your_key_here"

resp = requests.post(
    "https://stackpeek.web.app/api/v1/detect/batch",
    headers={"x-api-key": API_KEY},
    json={"urls": [
        "https://competitor1.com",
        "https://competitor2.com",
        "https://competitor3.com",
    ]}
)

for r in resp.json()["results"]:
    print(f"\n{r['url']}:")
    for t in r["technologies"]:
        print(f"  {t['category']}: {t['name']}")