jsDelivr

What jsDelivr actually is

jsDelivr is a free CDN for open source files, built around a tight integration with GitHub and npm: point a URL at cdn.jsdelivr.net, name a package and version, and the file is served from a global edge network — no account, no billing, no setup. It also proxies WordPress plugin assets and, through the projects it has absorbed over the years (BootstrapCDN in 2020, RawGit in 2021, OSSCDN in 2016), covers a large share of the front-end assets that ordinary websites load every day. The company behind it is Prospect One, the Kraków-based firm of founder Dmitriy Akulov, who started the project in May 2012; it is maintained by a small core team plus contributors and funded by industry sponsors.

The technical claim to fame is the multi-CDN architecture. Rather than buying capacity from one provider, jsDelivr runs on top of CDN networks donated by its sponsors — Cloudflare (since 2014), Fastly (2017), Bunny (2021), and Gcore (2022) — with custom servers in regions where those networks are thin, and a dedicated "Near China" set of locations to keep latency acceptable for Chinese users. Traffic is load-balanced and routed across providers, so a single CDN's outage or regional weakness does not take the service down. The origin runs as a Docker Swarm cluster across three datacenters. That design is why the service has scaled from 7 billion requests a month in 2015 to 130 billion in 2021 and 260 billion in March 2024 without becoming a business that sells plans.

URL design is worth a paragraph because it is most of the usability. A pinned URL looks like /npm/package@1.2.3/dist/file.js; ranges such as @1.2 or @latest resolve at request time to the newest matching release; GitHub and WordPress plugin assets follow the same pattern. Files are served with long cache headers when the version is immutable and short ones when a range can move. There is no dashboard to configure because there is nothing to configure — the package metadata is the configuration., not a toy: pinned and semver-ranged versions with automatic resolution to the latest matching release, a purge API, a public data API with per-package download statistics, on-the-fly SVG optimization, ES module support via esm.run, and a combine endpoint that returns multiple files in one response. There is also a "custom OSS CDN" program that gives open source projects their own subdomain on the same infrastructure.

Pricing: what you really pay

There is no pricing page because there is nothing to buy. jsDelivr states plainly that there are no bandwidth limits and no premium features — it is completely free to use by anybody, and the terms describe the CDN as publicly available without a subscription. The money comes from sponsors: CDN providers contribute bandwidth and locations, other companies contribute DNS, hosting, and services, and funding flows through GitHub Sponsors and Open Collective (the sponsor page explicitly frames contributions as paying for infrastructure and development hours).

The indirect cost is scoping. jsDelivr exists to serve open source; if you want to host your own private application assets, this is not the product, and even for public project assets the honest framing is that you are a guest on donated infrastructure with no contractual recourse. For production use on your own domain, a paid CDN or object storage with an SLA is the appropriate tool — compare options in our CDN category. For what it is designed for, the price-to-value ratio is about as good as infrastructure gets.

Performance & infrastructure

The edge footprint is the aggregate of its sponsors' networks plus its own machines: the homepage advertises more than 540 points of presence, and smart load-balancing routes each request to whichever provider is performing best for that user at that moment. Multi-CDN routing has been a jsDelivr staple since 2013, when Cedexis brought real-user-measurement routing; the 2022 DNS rebuild simplified that routing layer further. The result in our view is availability that is structurally better than any single CDN can offer — not because each provider is perfect, but because the failures don't correlate.

Volume is not a question mark. The history page records 30 billion monthly requests in 2018, 60 billion in 2019, 130 billion in 2021, 180 billion at the end of 2022, and 260 billion in March 2024 — a service carrying hundreds of billions of requests and multiple petabytes of traffic per month, with millions of websites using it. Those numbers appear across jsDelivr's own pages in slightly different forms (the homepage currently shows 150 billion requests and over 5,000 TB in the past month, while the GitHub Sponsors page cites over 250 billion requests and 12 PB), so treat them as order-of-magnitude rather than audited figures.

Caching behavior is the usual CDN contract: immutable versioned URLs cache essentially forever, and the semver-range URLs (@5 or @latest) cache for a short TTL and then update. The practical rule we tell people: pin versions in production so a package update can never change your page underneath you, and use ranges only where that risk is acceptable. A public status page (status.jsdelivr.com) is published, which is the closest thing to an operational commitment the service offers. If you want to compare raw delivery numbers against other infrastructure, our benchmarks track network-side performance across providers.

Where it falls short

The first limitation is contractual: no SLA, no support contract, no uptime guarantee. jsDelivr is transparent about this — the service is free and offered as-is — but it means that when your business depends on those URLs, your risk management is a fallback CDN, self-hosted copies of critical assets, or both. For most sites the multi-CDN design makes that belt-and-braces approach rarely necessary; for regulated or revenue-critical systems, "rarely" is doing a lot of work in that sentence.

Second, scope. Open source files on npm, GitHub, and WordPress plugins only. Your private assets, your video, your user uploads: out of scope. Content policies apply, and a package removal or a licensing dispute upstream can take a file away from you. The service is a distribution layer for the open source ecosystem, not a general-purpose storage or CDN product.

Third, operational opacity. Sponsorship-funded infrastructure means the capacity map and routing rules are the project's business, not yours, and there is no published performance SLA or per-region commitment. The stats across the project's own pages disagree with each other by meaningful margins (see above), which is a small honesty wobble on an otherwise well-documented service. And because the team is small and the product is free, feature requests and support are best-effort on GitHub.

Who should pick this

We pick jsDelivr for serving open source front-end assets in production: npm packages, GitHub releases, WordPress plugin files, and library CDNs where the alternative is vendoring every dependency yourself. It is our default recommendation for loading popular libraries on content sites, for demos and documentation, and for open source projects that want their users to get fast downloads without paying for bandwidth. The BootstrapCDN and RawGit mergers mean a lot of legacy URLs now live here anyway.

We would not pick it for private application bundles where you want asset integrity and an SLA under your own control, for anything requiring contractual recourse, or for content that must not depend on third-party policy decisions.

Two habits make jsDelivr safer in production. First, pin exact versions and use subresource integrity hashes in your script tags, so that even a CDN compromise or an upstream package rewrite cannot silently change what your page executes. Second, keep a self-hosted copy of anything whose disappearance would break your site. The pattern we use ourselves: pin versions via jsDelivr for widely used libraries, and keep mission-critical or custom assets on our own origin or a paid CDN with a fallback.

Key takeaways

• Free CDN for open source files (npm, GitHub, WordPress plugins) since 2012, founded by Dmitriy Akulov and run by Prospect One (Kraków, Poland).
• Multi-CDN architecture across Cloudflare, Fastly, Bunny, and Gcore plus custom servers and a "Near China" network — more than 540 points of presence advertised.
• Massive, proven scale: 260 billion monthly requests recorded in March 2024, with hundreds of billions and multiple petabytes per month today.
• Real CDN features: version pinning and semver ranges, purge API, download statistics API, ESM support (esm.run), file combining.
• No SLA, no support contract, no premium tier — risk management (pinned versions, asset fallbacks) is on you for critical paths.
• Best fit: production loading of open source libraries and project assets; poor fit: private assets or anything needing contractual uptime commitments.

Sources

• https://www.jsdelivr.com/
• https://www.jsdelivr.com/about
• https://www.jsdelivr.com/network
• https://www.jsdelivr.com/history
• https://github.com/sponsors/jsdelivr
• https://github.com/jsdelivr/jsdelivr/blob/master/Terms%20of%20Use.md
• https://opencollective.com/jsdelivr
• https://www.norrdia.com/privacy-policy/