Customize URL Tiers

Feedcanon applies URL normalization tiers to generate candidates, ordered from cleanest to least clean. The first candidate serving the same content wins.

Default tiers:

1. Tier 1 — Strip query, www, and trailing slash
2. Tier 2 — Strip www and trailing slash, keep query
3. Tier 3 — Keep www, strip trailing slash, keep query
4. Tier 4 — Keep www and trailing slash, keep query

INFO

Tracking parameters are stripped separately via the stripQueryParams option in FindCanonicalOptions, not per-tier. This ensures consistent param stripping across all tiers.

Normalization Options

Each tier accepts all NormalizeOptions except stripQueryParams:

Option	Default	Description
stripProtocol	false	Remove protocol (not recommended for feed URLs)
stripAuthentication	false	Remove user:pass@
stripWww	true	Remove www. prefix
stripTrailingSlash	true	Remove trailing / from paths
stripRootSlash	true	Remove / from root paths
collapseSlashes	true	/// → /
stripHash	true	Remove #fragment
sortQueryParams	true	Sort params alphabetically
stripQueryParams	—	Handled at top level, not per-tier
stripQuery	false	Remove entire query string
stripEmptyQuery	true	Remove empty ?
normalizeEncoding	true	Normalize %XX encoding
normalizeUnicode	true	NFC normalization
convertToPunycode	true	Convert IDN to Punycode

Examples

Minimal Tiers

Use a single tier with minimal normalization:

import { findCanonical } from 'feedcanon'

const url = await findCanonical('https://example.com/feed', {
  tiers: [{}], // No URL transformations, only query param stripping
})

Aggressive Tiers

Strip everything possible with a single tier:

import { findCanonical } from 'feedcanon'

const url = await findCanonical('https://example.com/feed', {
  tiers: [
    {
      stripWww: true,
      stripTrailingSlash: true,
      stripRootSlash: true,
      collapseSlashes: true,
      stripHash: true,
      sortQueryParams: true,
      stripEmptyQuery: true,
      normalizeEncoding: true,
      normalizeUnicode: true,
      convertToPunycode: true,
    },
  ],
})

Custom Stripped Params

Add your own tracking parameters (at the top level, not per-tier):

import { findCanonical } from 'feedcanon'
import { defaultStrippedParams } from 'feedcanon/defaults'

const url = await findCanonical('https://example.com/feed', {
  stripQueryParams: [
    ...defaultStrippedParams,
    'my_tracking_param',
    'internal_ref',
  ],
  tiers: [
    { stripWww: true, stripTrailingSlash: true },
    { stripTrailingSlash: true },
  ],
})

Preserve Query Params

Keep all query parameters (no stripping):

const url = await findCanonical('https://example.com/feed', {
  stripQueryParams: [], // Keep all params
  tiers: [
    { stripWww: true, stripTrailingSlash: true },
  ],
})

Default Stripped Parameters

Feedcanon strips 100+ tracking parameters by default. See defaultStrippedParams for the complete list.