Best TLDs for Startups and Tech Companies: The Rise of .io, .ai, and .co

The Changing Landscape of Startup Domains

The startup world has never been more diverse in its domain choices. While .com still reigns supreme—used by over 62% of funded startups in 2021—the number of startups choosing alternative TLDs has dramatically increased. From 14.7% in 2014 to 33.1% in 2018, the adoption of non-.com domains more than doubled, signaling a fundamental shift in how tech companies think about their online identity.

This isn't just about availability or cost. It's about identity, credibility within specific tech communities, and strategic brand positioning. When Greenhouse chose .io, Customer.io built their brand around it, and hundreds of AI companies flocked to .ai, they weren't just picking domains—they were making strategic statements about what kind of companies they wanted to be.

This guide examines the domain choices of thousands of venture-backed startups, analyzes the growth trajectories of tech-focused TLDs, and provides data-driven recommendations for choosing your startup's domain extension.

The Big Picture: Startup TLD Statistics

While .com remains the undisputed king of TLDs for the foreseeable future, the rapid growth of alternatives shows that startups are increasingly willing to embrace extensions that better match their industry focus, technical credibility, or brand identity.

.io - The Developer's Default

Why .io Became Synonymous with Tech Startups

Originally the country-code top-level domain (ccTLD) for the British Indian Ocean Territory, .iohas been completely recontextualized by the tech industry. The reference to "input/output" in computer science wasn't planned—it was a happy accident that tech founders seized upon.

The Numbers

• 1.1 million total registrations - Making it one of the most popular tech-focused TLDs
• 0.7% quarterly growth - Steady, sustained adoption
• Popular with SaaS and dev tools - Particularly strong in B2B software

Notable .io Success Stories

Companies like Framer.io, Greenhouse.io, and Customer.iohelped turn .io into a genre of its own. These weren't just domain choices—they became part of the brand identity. When you see a .io domain, you immediately think: developer tool, SaaS platform, or tech startup.

When to Choose .io

The .io Credibility Factor

In developer communities, a .io domain carries instant credibility. It signals that you understand tech culture, you're building for developers, and you're part of the modern SaaS ecosystem. For early-stage startups targeting technical users, .io can actually be more credible than .com.

.ai - The AI Boom Extension

The Fastest-Growing Startup TLD

If .io defined the 2010s startup era, .ai is defining the 2020s. Originally the country code for Anguilla, .ai has been wholly adopted by artificial intelligence companies, machine learning startups, and any tech company that wants to signal innovation in the AI space.

Explosive Growth Statistics

Why .ai Works for AI Companies

The alignment between extension and industry focus couldn't be more perfect. When Jenny.ai launched, the domain instantly communicated what the product was about. The extension does marketing work before users even visit the site.

In 2018, reflecting the rise of artificial intelligence within the startup ecosystem, .ai replaced .net as the third most popular alternative domain extension among venture-backed companies. This wasn't gradual—it was a rapid shift as AI became the hottest sector in tech.

Investment and Premium Pricing

The .ai extension has seen explosive growth in premium domain sales. With 20 of the top 100 high-value domain sales in 2024 being .ai domains, it's clear that investors and companies are willing to pay premium prices for the right .ai domain. Short, memorable .ai domains can command six or even seven-figure price tags.

When to Choose .ai

The Risk: Trend Dependence

While .ai is incredibly hot right now, some brand experts caution that tying your domain so explicitly to a current trend could limit long-term flexibility. If "AI" eventually becomes as generic as "digital" or "online," the extension might lose its distinctive signaling value. However, for companies that are genuinely focused on artificial intelligence, this specificity is a feature, not a bug.

.co - The .com Alternative

When .com Isn't Available

Originally the country code for Colombia, .co went global fast. Its resemblance to .com, the fact that it's short, clean, and easy to remember, made it a favorite among early-stage startups looking for a more affordable alternative to .com.

Strategic Positioning

Unlike .io and .ai, which signal specific industries or technologies, .co is more of a .com substitute—a way to get a short, clean domain when your ideal .com is unavailable or prohibitively expensive. The extension doesn't carry specific industry connotations, which can be an advantage for companies that don't want to be pigeonholed.

Notable .co Adopters

Big names helped cement .co as startup-friendly:

• AngelList (angel.co) - One of the most prominent startup platforms
• 500 Startups (500.co) - Major startup accelerator
• Bitly (bit.ly → also used bitly.co) - URL shortening service

When to Choose .co

The Type-In Traffic Consideration

The main risk with .co is that users might accidentally navigate to the .com version of your domain. This is especially true if your brand name is generic or if users hear about you verbally without seeing the written domain. Many successful .co companies eventually acquire the .com version as they scale.

Other Strong Startup TLD Options

.dev - Google's Developer Extension

Run by Google with 606,260 active registrations, .dev requires HTTPS by default, adding security and credibility. It's ideal for developer portfolios, open-source projects, coding boot camps, and developer tools. The forced encryption lends credibility among security-conscious developers.

Google's own platforms like web.dev and flutter.dev showcase the extension's credibility. For developer-focused brands, .dev can enhance credibility even more than .io in some circles.

.tech - Universal Tech Appeal

.tech has become one of the most popular gTLDs for the tech industry, with universal appeal across hardware, software, AI, cybersecurity, and emerging tech verticals. It's simple, direct, and clearly describes what you do.

The extension has been embraced by both startups and established brands, making it less "startup-specific" than .io but still tech-focused enough to signal industry alignment.

.app - For App Developers

Like .dev, .app requires valid SSL certificates, adding security and trust. It's particularly suitable for mobile app developers, SaaS platforms, and digital tools. If your startup revolves around app development or digital services, .app is a natural fit that immediately communicates your focus.

.xyz - The Wild Card

As of August 2024, .xyz is the most popular new generic top-level domain (gTLD) with approximately 4.16 million domains, accounting for 16.71% of gTLDs. While it doesn't have specific industry connotations, its generic nature and low cost have made it popular with experimental projects, side hustles, and companies that want to stand out as unconventional.

The Case for (Still) Choosing .com

Why 62% of Funded Startups Stick with .com

Despite the growth of alternative TLDs, over 62% of funded startups still choose .com. There are good reasons for this continued dominance:

When .com Is Worth the Premium

For consumer-facing startups, companies targeting non-technical audiences, or businesses planning eventual mass-market appeal, paying a premium for .com might be worth it. The type-in traffic, trust factor, and flexibility to pivot without domain constraints can justify higher acquisition costs.

The Upgrade Path

Many successful startups start with alternative TLDs and upgrade to .com as they scale. Twitter was originally at twttr.com, Instagram started as Burbn, and countless others have migrated. Starting with .io, .ai, or .co doesn't prevent you from eventually acquiring the .com—it just means you don't have to pay premium prices before you've validated your business.

Strategic Framework: Choosing Your Startup TLD

Key Decision Factors

1. Target Audience

• Developer/technical audience: .io, .dev, .tech work great and add credibility
• AI/ML focus: .ai signals industry alignment and innovation
• General consumers: .com provides universal trust and recognition
• Early adopters/tech-savvy: Alternative TLDs are perfectly acceptable

2. Budget Considerations

Premium .com domains can cost anywhere from $10,000 to millions. Alternative TLDs typically range from $10-100 per year for standard registrations. For early-stage startups with limited budgets, choosing an alternative TLD can preserve cash for product development and marketing.

3. Brand Strategy

• Industry-specific positioning: Use .ai, .io, or .tech to signal focus
• Broad market potential: .com or .co provide flexibility
• Developer credibility: .io or .dev can be more credible than .com in tech circles
• Future pivot possibility: Generic TLDs offer more flexibility

4. Type-In Traffic Risk

Consider how users will discover your site. If you rely heavily on word-of-mouth or offline marketing, .com reduces the risk of users typing the wrong extension. If most traffic comes from links, search, or direct marketing, the extension matters less.

5. Long-Term Vision

• Planning to acquire .com later: Alternative TLD can be a stepping stone
• Deep industry focus: Industry-specific TLD reinforces positioning
• Mass market eventual goal: .com might be worth the investment upfront

Real-World Startup Domain Decisions

Case Studies from Funded Companies

Companies That Chose Alternative TLDs

• Greenhouse.io - Built entire brand around .io, became industry standard for recruitment software
• Customer.io - .io reinforced technical credibility for developer-focused marketing platform
• Jenny.ai - .ai immediately communicated AI-powered writing assistant positioning
• AngelList (angel.co) - .co worked for startup community platform

Companies That Upgraded to .com

Many successful companies started with alternative TLDs and eventually acquired their .com:

• Cursor - Started at Cursor.sh, acquired Cursor.com for $399K after raising funding
• Numerous others - Acquired .com as they scaled and budgets allowed

The lesson: Your initial TLD doesn't lock you in forever. Many successful companies start with what they can afford and upgrade as they grow.

Future Trends in Startup Domains

Based on current growth trajectories and market data:

Expected Continued Growth

• .ai will continue explosive growth - As AI becomes more central to tech, expect continued high-value sales and new registrations
• .io maintains steady position - Well-established in developer communities, will continue steady 0.7% quarterly growth
• New TLDs will emerge - ICANN's next application round (2026-2027) will introduce new options
• .com will remain dominant - But alternative TLDs will claim larger market share

What This Means for Startups

The stigma around non-.com domains continues to fade, especially in technical communities. As more successful companies build on alternative TLDs, choosing .io, .ai, .dev, or other industry-specific extensions becomes less risky and more strategic.

For startups launching in 2025 and beyond, the key is matching your TLD to your audience, budget, and brand strategy—not just defaulting to .com because "that's what everyone does."