How .io Became the Startup TLD

## How .io Became the Startup TLD Ask any software developer to name the domain extension most associated with technology startups, and the answer is almost universally `.io`. It appears on everything from venture-backed unicorns to one-person side projects: `github.io`, `gitlab.io`, `fly.io`, `linear.app` (even companies that now use other extensions often passed through `.io` at launch). Yet `.io` has nothing to do with technology. It is the ccTLD (Country-Code Top-Level Domain) assigned to the British Indian Ocean Territory, a remote archipelago in the Indian Ocean with no permanent civilian population. This is the story of how geography became irrelevant and a two-letter code became a global tech brand. TLD Finder ## The British Indian Ocean Territory The British Indian Ocean Territory (BIOT) consists primarily of the Chagos Archipelago, a group of atolls and islands controlled by the United Kingdom since the 1960s. The islands are most notable for hosting the Diego Garcia military base, a joint UK-US facility of significant strategic importance in the Indian Ocean. There are no civilians; the original Chagossian inhabitants were controversially displaced to make way for the base. When IANA began assigning two-letter ccTLD (Country-Code Top-Level Domain) codes to nations and territories in the 1980s, the British Indian Ocean Territory received `.io`. The assignment followed ISO 3166-1 alpha-2 codes, a standard list of country abbreviations maintained by the International Organization for Standardization. For most of its early existence, `.io` was administered by a small UK-based operation and saw minimal registration activity. It was an obscure ccTLD (Country-Code Top-Level Domain) with almost no natural registrant base — the territory had no civilian population to buy `.io` domains. ## The Input/Output Connection The transformation of `.io` began in the mid-2000s with a simple observation: in computer science, "I/O" stands for "input/output." Every programmer learns this abbreviation in their first weeks of study. It appears in function names (`fopen()`, `console.io`), operating system concepts (I/O scheduling, disk I/O), and developer documentation everywhere. Early tech startups began gravitating to `.io` domains around 2008–2012 for this reason. A `.io` domain communicated something to a technical audience without any explicit statement: this is a developer tool, a technical product, a startup run by engineers for engineers. The domain extension became a signaling mechanism within technical communities. Pricing also played a role. During the late 2000s and early 2010s, desirable `.com` domains for short, memorable names were almost entirely registered — and those on the aftermarket commanded premium prices. `.io` domains, by contrast, were available and relatively affordable. ## GitHub Pages and the Network Effect A pivotal moment came when GitHub launched GitHub Pages, a free static site hosting service, with domains in the format `username.github.io`. Suddenly millions of developers had `.io` domains for their personal sites and project documentation. This was not a branding decision by GitHub in the traditional sense; it was a technical choice that produced enormous brand impact. When a developer sees `your-project.github.io`, the `.io` extension becomes normalized — not exotic. The association: serious open-source projects live at `.io` addresses. Within a few years, the extension was no longer the domain equivalent of an obscure archipelago; it was synonymous with developer culture. Numerous significant tech brands registered their primary domains under `.io`: - **`replit.io`** — Code execution platform (later moved to `replit.com`) - **`fly.io`** — Application deployment platform - **`linear.app`** — (moved from `.io`) - **`notion.io`** — (Notion initially tested `.io` before settling on `.so` and `.notion.site`) - **`hackerone.com`** — (explored `.io` for subservices) - **`io.net`** — Decentralized GPU computing Venture capital also validated `.io` through portfolio company naming. When prominent VCs consistently funded companies with `.io` domains, limited partners, press, and other founders internalized the association. ## The BIOT Controversy The cultural dominance of `.io` obscures a persistent ethical controversy: the revenue from `.io` Domain Registration fees flows to the Registry Operator, which for most of `.io`'s history was a UK-based company called Internet Computer Bureau (ICB). The Chagossian people, displaced from their homeland for military purposes, received none of this revenue. The Chagos Archipelago sovereignty dispute has been ongoing for decades. The UK government has faced numerous legal challenges and international censure over its administration of the territory. In 2019, the International Court of Justice issued an advisory opinion that the UK's control over the Chagos Islands violated international law. The UN General Assembly voted for the UK to return the islands to Mauritius. This political situation creates existential uncertainty for `.io` as a TLD (Top-Level Domain). ## The Possible Disappearance of .io Under IANA and ICANN rules, a ccTLD (Country-Code Top-Level Domain) is assigned to a country or territory based on its ISO 3166-1 listing. If the British Indian Ocean Territory ceases to exist as a recognized entity — through transfer of sovereignty to Mauritius — then `IO` could be removed from the ISO 3166-1 alpha-2 list, triggering a IANA review of the `.io` delegation. In 2024, the UK and Mauritius announced a historic agreement to transfer sovereignty of the Chagos Islands to Mauritius. The deal remained politically contested in the UK as of early 2026, but its eventual implementation could trigger exactly this scenario. If `IO` were removed from ISO 3166-1, IANA would begin a country code retirement process. This has happened before: `.yu` (Yugoslavia) was retired in 2010 after the country dissolved, and `.su` (Soviet Union) remains in an extraordinary limbo as the last relic of a dissolved state in the DNS Root Zone. `.tp` (East Timor) was retired in 2015 after the territory became `.tl` (Timor-Leste). The retirement process is slow — `.yu` took years from the start of the retirement process to final deactivation — and ICANN has signaled it would provide substantial transition time for affected registrants. But the theoretical possibility of `.io` eventually being retired represents a genuine long-term risk for the hundreds of thousands of companies relying on it as their primary Domain Registration. ## The Current State of .io Despite the political uncertainty, `.io` continues to thrive. The extension is managed by the ICB registry and distributed through hundreds of Domain Registrar partners worldwide. Registration counts have grown consistently and are estimated at 300,000–400,000 domains as of 2026 — a large number for a ccTLD (Country-Code Top-Level Domain), though small compared to `.com`'s 160 million. Pricing has crept up over the years. `.io` domains now typically cost $30–$60 per year at retail, roughly double the cost of a standard `.com`. The premium pricing reflects the extension's brand value among tech communities, and it has not noticeably dampened demand. ## What .io Teaches About Domain Brand Building The `.io` story illustrates that brand value in the domain name system is emergent rather than designed. No committee decided that `.io` should be the startup TLD. It happened because: 1. A technical abbreviation happened to match a country code 2. Early adopters in a taste-making community chose it 3. A major platform (GitHub) normalized it through free hosting 4. Venture capital signaling reinforced the association 5. Network effects made it self-perpetuating This organic brand-building is impossible to fully replicate, but it suggests that the "right" domain extension for any community is the one that community actually uses — not the one that seems most logical from the outside. The .ai Gold Rush: How Anguilla Hit the Jackpot .tv, .fm, .dj: When Countries Become Brands ## Who Controls .io Today and How Registration Works The `.io` ccTLD (Country-Code Top-Level Domain) is currently managed by Internet Computer Bureau (ICB), a UK-based company that has operated the registry since the 1990s. ICB distributes `.io` domain registrations through a global network of accredited Domain Registrar partners. The registration process for `.io` is similar to any other ccTLD (Country-Code Top-Level Domain) or gTLD (Generic Top-Level Domain): 1. Check availability through a Domain Registrar offering `.io` domains 2. Register at the retail price ($30–$60/year depending on registrar) 3. Configure your DNS (Domain Name System) records as needed 4. Renew annually to maintain registration Unlike some ccTLDs that impose local presence requirements (you must be a resident or business in the country), `.io` has no such restrictions. Any person or organization anywhere in the world can register a `.io` domain, which has been essential to its global adoption. WHOIS records for `.io` domains follow the standard format. Contact information is held by ICB and can be queried through `whois` command-line tools or the IANA delegation record for `.io`. ## .io in the Tech Startup Ecosystem: Data and Patterns Research into `.io` domain usage reveals clear patterns: **Startup stage preference**: `.io` is disproportionately used by early-stage startups (seed and Series A companies). As companies mature and raise larger rounds, many migrate to `.com` — which is perceived as more "enterprise" and carries stronger recognition with non-technical users, including enterprise buyers, investors, and the general public. **Geographic concentration**: Despite being a supposedly global extension, `.io` usage is concentrated in tech hubs: San Francisco Bay Area, New York, London, Berlin, Tel Aviv, Singapore, and Toronto. These are the cities where developer culture and startup culture overlap most intensely. **Category clustering**: Developer tools, API platforms, SaaS products targeting technical users, and infrastructure companies show the highest `.io` penetration. Consumer-facing applications — even those built by developers — are more likely to launch on `.com` to avoid confusing non-technical users. **Venture capital signaling is bidirectional**: VCs have internalized `.io` as a "startup domain," which means a `.com` address from an early-stage company can signal the founders are from outside the typical tech startup culture. In Silicon Valley, a Series A company still on `.io` is unremarkable; a seed-stage company already on `.com` sometimes raises eyebrows. ## The Migration Question: When Should .io Companies Move to .com? Many `.io` companies eventually face the migration question. The answer typically depends on several factors: **Primary audience**: If the product is sold primarily to developers and technical users who understand and trust `.io`, there is no urgency to migrate. If the product is expanding to non-technical buyers — procurement managers, HR departments, C-suite executives — `.com` migration is worth considering. **Brand equity**: Companies with strong brand recognition under their `.io` domain (GitHub, Fly.io) face higher migration costs than those where the brand is still being established. GitHub's decision to keep `github.io` for Pages while operating `github.com` as the primary site was correct given their established brand equity. **SEO considerations**: Domain migrations carry SEO risk. Properly executed with full redirect chains and updated sitemaps submitted to search engines, the ranking impact is typically temporary (weeks to a few months). Poor execution — missing redirects, slow rollout, incomplete link updates — can cause lasting damage. **Cost**: Short, relevant `.com` domains for most startup names are either unavailable or available only in the domain aftermarket at prices from $5,000 to $500,000+. The `.io` domain often exists precisely because the equivalent `.com` was either taken or unaffordable at launch. ## Conclusion `.io` is among the most remarkable stories in the domain name industry: a ccTLD (Country-Code Top-Level Domain) assigned to an uninhabited military archipelago that became the preferred domain extension of the global startup ecosystem. Whether it survives the political resolution of the Chagos sovereignty dispute remains to be seen, but its fifteen years as the de facto startup TLD (Top-Level Domain) represent a case study in how domain extensions acquire cultural meaning independent of their technical origins. TLD Comparison Tool