What causes "license not found" in badges/shields?

Add a @license declaration to the user script header and update it on Greasyfork

badges/shields · warning · InvalidResponse

license not found

Error message

license not found

What it means

The Greasyfork license service throws this InvalidResponse when the Greasyfork API returns license === null, meaning the user script has no declared license. The service requires a non-null license string to strip the ' License' suffix and render the badge.

Source

Thrown at services/greasyfork/greasyfork-license.service.js:25

  static route = { base: 'greasyfork', pattern: 'l/:scriptId' }

  static openApi = {
    '/greasyfork/l/{scriptId}': {
      get: {
        summary: 'Greasy Fork License',
        parameters: pathParams({
          name: 'scriptId',
          example: '406540',
        }),
      },
    },
  }

  static defaultBadgeData = { label: 'license' }

  transform({ data }) {
    if (data.license === null) {
      throw new InvalidResponse({
        prettyMessage: 'license not found',
      })
    }
    // remove suffix " License" from data.license
    return { license: data.license.replace(/ License$/, '') }
  }

  async handle({ scriptId }) {
    const data = await this.fetch({ scriptId })
    const { license } = this.transform({ data })
    return renderLicenseBadge({ licenses: [license] })
  }
}

View on GitHub (pinned to 766fd8bc89)

Solutions

Add a @license declaration to the user script header and update it on Greasyfork
Set the license in the script's code metadata (e.g. // @license MIT) and push an update
If no license is intended, remove the license badge from the README

Example fix

// before (script header)
// ==UserScript==
// @name My Script
// ==/UserScript==
// after
// ==UserScript==
// @name My Script
// @license MIT
// ==/UserScript==

Defensive patterns

Strategy: type-guard

Validate before calling

const data = await (await fetch(`https://www.greasyfork.org/api/v2/scripts/${scriptId}`)).json()
if (data.license == null) console.warn('This script declares no license')

Type guard

const hasLicense = (data) => data != null && typeof data.license === 'string' && data.license.length > 0

Try / catch

try {
  const { license } = service.transform({ data })
} catch (e) {
  if (e.prettyMessage === 'license not found') {
    // render 'no license' badge
  } else throw e
}

Prevention

Always include // @license in user script metadata
Check the Greasyfork API response's license field before adding the badge
For scripts without a license, use a different badge type

When it happens

Trigger: Requesting a license badge for a script whose author did not set a license in the script metadata; scripts using @@license==none or an unspecified license on Greasyfork.

Common situations: Legacy scripts uploaded before license was mandatory on Greasyfork; authors who left the @license metadata out; script deleted its license field on update.

Related errors

AI-assisted analysis of badges/shields@766fd8bc89 (2026-08-30). Data as JSON: /api/errors/0a78e749fc601003. Report an issue: GitHub.