Software Alternatives & Startups

cdnjs VS IsDown.app

Compare cdnjs VS IsDown.app and see what are their differences

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cdnjs logo cdnjs

An open source community driven JS/CSS CDN.

IsDown.app logo IsDown.app

When a vendor goes down, does your team find out in seconds or after users start complaining? IsDown monitors 6,000+ official status pages and alerts your team within seconds across Slack, PagerDuty, Datadog, and more. 14-day free trial
  • cdnjs Landing page
    Landing page //
    2022-06-17
  • IsDown.app All Your Vendors. One Real-Time View.
    All Your Vendors. One Real-Time View. //
    2026-03-03
  • IsDown.app 26 Integrations. Alerts Where Your Team Already Works.
    26 Integrations. Alerts Where Your Team Already Works. //
    2026-03-03
  • IsDown.app Monitor Any Vendor. Filter What Matters.
    Monitor Any Vendor. Filter What Matters. //
    2026-03-03
  • IsDown.app One Status Page for Your Whole Team.
    One Status Page for Your Whole Team. //
    2026-03-03
  • IsDown.app Full Incident Context, Not Just an Alert.
    Full Incident Context, Not Just an Alert. //
    2026-03-03
  • IsDown.app Vendor Accountability, Backed by Data.
    Vendor Accountability, Backed by Data. //
    2026-03-03

IsDown was built out of frustration at 4 AM. Nuno Tomas, founder and on-call engineer, spent 30 minutes debugging an alert before realising the cloud provider had an outage posted on their status page, but nobody was watching it. That night, he decided there had to be a better way.

Today, IsDown monitors 6,000+ cloud and SaaS services, has performed over 1 billion status checks, has detected 520,000+ outages, and has sent 5.2 million+ notifications. Trusted by IT, DevOps, and engineering teams since 2020.

What makes IsDown different: it reads official vendor status pages directly, not just crowdsourced reports. Combined with early detection signals, it catches outages before vendors acknowledge them, sometimes hours ahead. In January 2026 alone, IsDown detected 101 incidents that vendors never officially reported.

Key capabilities: - Monitor 6,000+ services from one dashboard. Filter by service, component, or severity. - Get alerts within seconds in Slack, PagerDuty, Datadog, Microsoft Teams, Incident.io, FireHydrant, Grafana, Discord, SMS, and wherever your team works. - Track scheduled maintenance across all vendors in a live feed and calendar, so nothing slips through unnoticed. - Create public or private hosted status pages with your own domain and branding. - Monitor your own APIs, endpoints, and SSL certificates from US, EU, and Asia. - Built for enterprise: SSO (SAML, OAuth), SOC 2 Type II in progress, MCP Server for AI assistant queries.

Setup takes 5 minutes. No engineering required. 14-day free trial, no credit card needed.

cdnjs

Website
cdnjs.com
Pricing URL
-
$ Details
Platforms
-
Release Date
-

IsDown.app

Website
isdown.app
$ Details
paid Free Trial $27 / Monthly (Starter)
Platforms
Web
Release Date
2020 May
Startup details
Country
Portugal
City
Lisbon
Founder(s)
Nuno Tomás

cdnjs features and specs

  • Wide range of libraries
    cdnjs offers a vast collection of JavaScript libraries, allowing developers to access and integrate them easily into their projects.
  • Enhanced Performance
    By using a CDN like cdnjs, resources are delivered from servers closest to the user, reducing loading times and improving website performance.
  • Reliability
    cdnjs is supported by well-established infrastructure, ensuring uptime and reliability when serving files.
  • Easy Versioning
    Developers can easily specify which version of a library they wish to use, providing control and flexibility in management.
  • Cost-effective
    Being a free service, cdnjs allows developers to leverage CDN capabilities without incurring costs.

Possible disadvantages of cdnjs

  • Dependency on Third-party
    Relying on an external CDN means that developers are dependent on their uptime and service quality.
  • Privacy Concerns
    Using a CDN can lead to potential data privacy issues, as user requests are routed through third-party servers.
  • Version Mismatch
    If not carefully managed, there can be inconsistencies in library versions across different environments, leading to potential conflicts.
  • Limited Offline Support
    Since cdnjs relies on internet connectivity, access to these libraries is compromised if there is no or poor internet connection.

IsDown.app features and specs

  • Status Dashboard
  • Multiple Team Boards
  • Slack App
  • Zapier Integration
  • Scheduled maintenances feed
  • Weekly Digest
  • Datadog Integration
  • Uptime Monitoring
  • Keyword Monitoring
  • SSL Monitoring
  • PagerDuty Integration
  • Custom Endpoint Monitoring
  • Public Status Pages
  • Private Status Pages
  • Early Outage Detection
  • SSO / SAML
  • Microsoft Teams Integration
  • Incident.io Integration
  • Historical Uptime Data
  • MCP Server
  • Multi-region Monitoring

Analysis of cdnjs

Overall verdict

  • Yes, cdnjs is generally considered a good service for hosting front-end libraries.

Why this product is good

  • cdnjs is a widely-used content delivery network that provides developers with access to a large repository of open-source JavaScript and CSS libraries. It's known for its reliability, speed, and ease of use. The platform is backed by Cloudflare, ensuring fast delivery and minimized latency. Additionally, cdnjs offers a vast selection of libraries, regular updates, and easy integration into web projects.

Recommended for

  • Developers looking for a reliable CDN to host JavaScript and CSS libraries.
  • Projects requiring quick and easy access to popular front-end libraries.
  • Web applications that need to ensure optimal performance and fast loading times.
  • Teams seeking a hassle-free way to manage and include third-party libraries in their codebase.

cdnjs videos

Making Your Web Site Faster With CDNJS

IsDown.app videos

No IsDown.app videos yet. You could help us improve this page by suggesting one.

Add video

Category Popularity

0-100% (relative to cdnjs and IsDown.app)
CDN
100 100%
0% 0
Monitoring Tools
0 0%
100% 100
Cloud Computing
100 100%
0% 0
Website Monitoring
0 0%
100% 100

Questions & Answers

As answered by people managing cdnjs and IsDown.app.

What makes your product unique?

IsDown.app's answer:

IsDown monitors official vendor status pages directly, not just crowdsourced reports. This means alerts include real incident context: what broke, which components are affected, and real-time resolution status. Not just "something is down." Combined with crowdsourced early detection signals, IsDown can catch outages before vendors acknowledge them. In January 2026 alone, IsDown detected 101 incidents that vendors never officially reported. Every team monitoring cloud services already has uptime tools that ping their own URLs. IsDown tells you what is happening with the third-party services your stack depends on, before your users feel it.

Why should a person choose your product over its competitors?

IsDown.app's answer:

Three reasons:

  1. Coverage: 6,000+ services monitored. If your vendor has a status page, IsDown monitors it.
  2. Speed and context: Alerts go out within seconds of an incident, with full context including affected components, official vendor description, and real-time updates. Not just a notification that something is wrong.
  3. IsDown does not replace your existing tools, it completes them. UptimeRobot and Pingdom tell you your own services are down. IsDown tells you which of your third-party vendors caused it, and exactly what is happening on their end. Setup takes 5 minutes. No engineering required.

How would you describe the primary audience of your product?

IsDown.app's answer:

IsDown is built for IT managers, DevOps engineers, and SREs at companies that rely on multiple cloud and SaaS services, which means any team running on cloud infrastructure. The core audiences are DevOps and SRE teams who are on-call and need to know instantly when a third-party service causes an incident; IT managers responsible for vendor oversight and SLA compliance; MSPs and agencies managing cloud infrastructure for multiple clients; and engineering teams who want to stop wasting time debugging problems that turn out to be vendor outages. Customers span SaaS companies, schools, DevOps agencies, and enterprise IT teams across industries.

What's the story behind your product?

IsDown.app's answer:

IsDown was built out of frustration at 4 AM. Nuno Tomas, the founder, was on-call when a PagerDuty alert woke him up. After 30 minutes of debugging, he realised the problem was not his code. It was the cloud provider. They had posted an outage on their status page, but nobody on the team was watching it. That night, he decided there had to be a better way. He built the first version of IsDown so his team would never be the last to know about a vendor outage. Founded in 2020, IsDown has since grown to monitor 6,000+ services, perform over 1 billion status checks, detect 520,000+ outages, and send 5.2 million+ notifications. The same problem Nuno solved for his team that night is now solved for IT, DevOps, and engineering teams around the world.

Who are some of the biggest customers of your product?

IsDown.app's answer:

IsDown is used by IT, DevOps, and engineering teams across SaaS companies, MSPs, DevOps agencies, schools, and enterprise IT departments.

Which are the primary technologies used for building your product?

IsDown.app's answer:

IsDown is a web-based SaaS application. The core product runs on modern cloud infrastructure with multi-region monitoring across US, EU, and Asia to ensure reliable status checks and fast alert delivery worldwide. IsDown integrates directly with Slack, PagerDuty, Datadog, Microsoft Teams, Incident.io, FireHydrant, Grafana, Rootly, Zendesk, and more, connecting alerts to wherever your team already works. For teams using AI assistants, IsDown offers an MCP (Model Context Protocol) Server that allows querying IsDown data directly from AI tools like Claude or ChatGPT.

User comments

Share your experience with using cdnjs and IsDown.app. For example, how are they different and which one is better?
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Social recommendations and mentions

Based on our record, cdnjs should be more popular than IsDown.app. It has been mentiond 17 times since March 2021. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.

cdnjs mentions (17)

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IsDown.app mentions (6)

  • Top 10 Statuspage.io Alternatives in 2025
    A specialized status page aggregator designed for internal team communication and vendor dependency monitoring. Unlike public status page creators, IsDown monitors 4,500+ third-party vendor status pages (AWS, Azure, GitHub, Stripe, etc.) and lets you create private status pages with SSO protection. - Source: dev.to / 9 months ago
  • Build or Buy Your Third-Party Monitoring System: Decision Guide
    Consider your growth trajectory. Will you be monitoring 10 services or 1000? Commercial solutions like IsDown are designed to scale effortlessly, while custom solutions often require significant rework as requirements grow. - Source: dev.to / 12 months ago
  • Best Downdetector Alternatives for Outage Monitoring in 2025
    Among them, IsDown stands out as a robust, business-focused solution. With real-time alerts, aggregated data from thousands of services, seamless integrations, and customizable dashboards, IsDown helps businesses stay ahead of outages and reduce downtime. Its combination of official updates and crowdsourced insights ensures accurate and timely information for faster response times. - Source: dev.to / about 1 year ago
  • Bring third-party incidents into Better Stack
    The Better Stack integration is included with every paid IsDown plan. Sign up for a free 14-day trial — or open Alerts & Integrations in your current IsDown account and add Better Stack now. Your team will see live incidents from AWS, Stripe, GitHub, and hundreds more, all inside the queue they already trust. - Source: dev.to / over 1 year ago
  • Connect all your vendors status pages to your Better Stack account
    Now you can monitor third-party outages right in your Better Stack account with https://isdown.app . What will you get? Single incident feed – Internal alerts and third-party outages appear in the same view. - Source: Hacker News / over 1 year ago
View more

What are some alternatives?

When comparing cdnjs and IsDown.app, you can also consider the following products

CloudFlare - Cloudflare is a global network designed to make everything you connect to the Internet secure, private, fast, and reliable.

StatusGator - Early outage alerts for every app you rely on

Amazon CloudFront - Amazon CloudFront is a content delivery web service.

UptimeRobot - Free Website Uptime Monitoring

KeyCDN - KeyCDN is a high-performance Content Delivery Network (CDN). Lowest price globally at $0.04/GB with HTTP/2 Support and free Origin Shield.

Phare.io - Keep your website up and running, empower your team with efficient incident management and keep your users informed during hard times.