Redirect checking with history.

Follow redirect chains and detect changes over time. Every check is stored, so you can look up what a URL did last week or last month.

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Zero SSRF risk

We block private IPs, cloud metadata, and IPv6 ranges. Safe URL checking without building your own validation.

100% reproducible

Every check is stored. Look up what a URL did last week, or see when its redirect behavior changed.

1 line integration

Run npx 3xx check URL. Sign up with your email for 100 free requests, then upgrade when you need more.

Use it anywhere

CLI or curl.

$ npx 3xx check https://t.co/example

First run? Enter your email to get started.

Email: [email protected]

→ Check your inbox for a login link.

301 https://t.co/example → https://twitter.com/i/web/status/12345ms

302 https://twitter.com/... → https://x.com/user/status/12352ms

200 https://x.com/user/status/12338ms

3 hops · 135ms · chain_hash: a8f2...

Every redirect chain is recorded

Look up what a URL did last week. See when its redirect behavior changed. This data can’t be backfilled.

{
  "id": "chk_01HN5V8XQR...",
  "final_url": "https://x.com/user/status/123",
  "final_status": 200,
  "chain": [
    {
      "status": 301,
      "from": "https://t.co/example",
      "to": "https://twitter.com/...",
      "ms": 45
    },
    {
      "status": 302,
      "from": "https://twitter.com/...",
      "to": "https://x.com/user/...",
      "ms": 52
    }
  ],
  "chain_hash": "a8f2c3...",
  "flags": {
    "cross_domain": true,
    "has_loop": false
  },
  "total_ms": 135
}

chain_hash

A hash of the redirect chain. When this changes, the URL started redirecting somewhere different. Query history to see when.

chain

Each hop: status code, source, destination, latency. Private IPs and metadata endpoints are blocked.

flags

Answers to common questions: Did it cross domains? Did it loop? Are there tracking parameters?

402 / 429

402 means quota exceeded—stop retrying. 429 means rate limited—wait, then retry.

Pricing

Every plan starts with 100 free requests. Upgrade only when you need more.

Starter

For makers and small projects

$12/month

50K requests/month

50K requests/month
CLI & API access
Historical queries
Email support

Developer

For production use

$29/month

250K requests/month

250K requests/month
Batch processing
Priority support
Usage analytics

Team

For CI/CD and monitoring

$79/month

1M requests/month

1M requests/month
Monitors & webhooks
Team seats
SLA guarantee