.io domains
Originally assigned as the country-code TLD for the British Indian Ocean Territory in 1997, .io was repurposed for open global registration after its administrator began offering it commercially to international registrants. The extension gained rapid traction in the technology and startup community due to its overlap with I/O — the computing abbreviation for input/output — a concept fundamental to software, hardware, and systems design. By the 2010s, .io had become one of the most recognized domain extensions among developers, tech startups, and SaaS companies worldwide. The underlying ccTLD origin has become largely incidental to its established identity in the technology sector. Note: Following the establishment of the Chagos Islands as a sovereign territory of Mauritius, the long-term future of .io as a ccTLD has been subject to ongoing discussion, though no changes to its operation have been announced.
The .io domain is the most widely adopted tech-sector domain extension outside of .com, recognized globally as a signal of technology, innovation, and startup culture. Originally the country-code TLD for the British Indian Ocean Territory, it has been embraced by the developer and startup community for its association with the I/O computing concept. There are no registration restrictions, making it available to any individual or business worldwide. Whether you are launching a SaaS product, developer tool, or tech startup, .io carries immediate credibility with technical audiences and investors.
What to know
- - Originally the ccTLD for the British Indian Ocean Territory, now widely adopted as the de facto tech startup domain globally.
- - The I/O abbreviation — standing for input/output — gives the extension deep resonance with developers, engineers, and technical audiences.
- - No registration restrictions — open to individuals, businesses, and organizations worldwide.
- - Widely recognized by investors and press as a signal of a technology or software product.
- - Higher registration and renewal costs than most gTLDs, reflecting strong demand in the startup and tech community.
Who uses .io
Tech Startups
The single most recognized domain extension for early-stage technology companies, signaling a digital-native, innovation-focused identity to investors and early adopters.
SaaS Products
A natural fit for software-as-a-service platforms where the .io extension is immediately understood as a product domain by business and technical buyers alike.
Developer Tools & APIs
Ideal for command-line tools, SDKs, APIs, and developer platforms where the I/O association reinforces the product's technical nature.
Open-Source Projects
Widely used by open-source libraries and frameworks that want a clean, modern domain that resonates with the global developer community.
Portfolios & Personal Sites
A credible choice for software engineers, data scientists, and technical professionals building a personal brand within the tech industry.
Naming guidance
Keep the name short — one or two words at most — since .io works best when the full domain reads as a crisp product or brand name. Avoid long or hyphenated names, as .io's strength lies in brevity and memorability. Budget for higher-than-average renewal fees when comparing total cost of ownership against alternatives like .com or .co.
Check availability
Search for your name as a .io domain.
.io vs the alternatives
When to choose a different extension instead.
Choose .com when targeting mainstream consumer audiences, non-technical buyers, or markets where .io is less recognized as a tech-sector signal.
Choose .dev for a developer-specific tool, portfolio, or open-source project where the Google-operated extension and HTTPS requirement align with your technical brand.
Choose .co for a broader business identity where you want a short, global domain without the tech-sector connotations of .io.
Choose .app for a consumer-facing mobile or web application where communicating the product type to non-technical users is a priority.
Choose .tech for a technology company or event where the audience spans both technical and non-technical stakeholders and a more literal extension is preferred.
Pricing
Register
$80.00/yr
Renew
$80.00/yr
Transfer
$80.00/yr
Registration and renewal prices are the same - no introductory rates.
Free WHOIS privacy included on this extension.
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Related extensions
.com
The .com domain is the world's most recognized and trusted domain extension, with no registration restrictions and global availability.
.dev
The .dev domain is the go-to extension for software developers, engineering teams, and technology projects.
.co
The .co domain is a globally recognized, open alternative to .com with no registration restrictions.
.app
Whether you're an indie developer launching your first mobile app or an enterprise publishing a full software suite, .app is the domain extension built for software products of every kind.