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Comparison

cdnjs vs jsDelivr

cdnjs and jsDelivr both land on Worth it.

cdnjs

cdnjs.com

Worth it
Confidence: Medium

Use it if you need a free, zero-maintenance way to serve popular open-source libraries . Cloudflare's network makes it dependable.

Read the full report

cdnjs versus jsDelivr
ComparecdnjsjsDelivr
VerdictWorth itWorth it
Best forFrontend devs serving popular JS/CSS librariesOpen-source library authors
Who it's not forGDPR-strict or privacy-sensitive sites . third-party scripts share visitor IPsCommercial apps needing SLAs or support contracts
PrivacyInfrastructure is hardened (HSTS preloaded), but cdnjs suffered a critical RCE in 2021 . patched; concentration risk remains.⁴No CVEs against the service itself in sources; a 2023 incident served already-removed malicious npm packages used in phishing.
Support qualityCommunity-run open source; no SLANo support-quality evidence in sources
Public sentimentDevelopers treat cdnjs as the dependable free default, but a vocal contingent now argues public CDNs create more risk than benefit.⁸Users on Reddit and G2 call it one of the best free JS CDNs for offloading scripts, but complain when outages and 404s break their sites.
Biggest gotchaSupply-chain concentration: one cdnjs compromise reaches every site using it . 2021 proved the risk⁴Free means no SLA: its outages and 404s become your site's incidents. Pin exact versions.

Pick cdnjs when

  • Frontend devs serving popular JS/CSS libraries
  • Prototypes, demos, and small business sites
  • Docs and blogs wanting zero build tooling
  • Open-source projects distributing browser builds

When cdnjs is not a fit

  • GDPR-strict or privacy-sensitive sites . third-party scripts share visitor IPs
  • Mission-critical apps that cannot tolerate third-party outages . self-host
  • Private or custom code . cdnjs hosts public open-source libraries only
  • Teams needing SLAs or vendor support . none exists

Pick jsDelivr when

  • Open-source library authors
  • Front-end devs loading npm/GitHub files
  • Demos, docs, and prototypes
  • Offloading static JS from small servers

When jsDelivr is not a fit

  • Commercial apps needing SLAs or support contracts
  • First-party production assets with uptime guarantees
  • Teams that can't accept third-party dependency on critical paths
  • Enterprises wanting vendor accountability and contracts

Sources

  1. cdnjs official sitecdnjs.com
    official
  2. Migrating cdnjs to Cloudflare's Developer Platformblog.cloudflare.com
    official
  3. Cloudflare's Handling of an RCE Vulnerability in cdnjsblog.cloudflare.com
    security
  4. Critical Cloudflare CDN flaw allowed compromise of 12% of all sitesbleepingcomputer.com
    security
  5. cdnjs always free . FreeTier.cofreetier.co
    review
  6. CloudFlare vs cdnjs . StackSharestackshare.io
    review
  7. Legitimate interest and loading jQuery from CDN . Reddit r/gdprreddit.com
    review
  8. Public CDNs Are Useless and Dangerous . httptoolkithttptoolkit.com
    security
  9. Why by default Asp.Net Core references cdnjs . Stack Overflowstackoverflow.com
    review
  10. Usage statistics and market share of CDNJS . w3techsw3techs.com
    review
  11. CDNjs vs JSdelivr . GitHub issuegithub.com
    review
  12. htmx CDN Bad Gateway . Reddit r/htmxreddit.com
    review
  13. jsdelivr/jsdelivr . GitHub repogithub.com
    official
  14. jsDelivr homepagejsdelivr.com
    official
  15. Our Network . jsDelivrjsdelivr.com
    official
  16. JSDelivr . Wikipediaen.wikipedia.org
    news