⚡ Quick Answer
.io = Tech-forward, developer audience, higher price
.co = More mainstream, company abbreviation, lower price
Both are acceptable for startups. Choose based on your audience.
Side-by-Side Comparison
| Factor | .io | .co |
|---|---|---|
| Origin | British Indian Ocean Territory | Colombia |
| Common Interpretation | "Input/Output" (tech) | "Company" |
| Price Range | $40-60/year | $25-35/year |
| Tech Credibility | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐ |
| Mainstream Appeal | ⭐⭐⭐ | ⭐⭐⭐⭐ |
| Confusion Risk | Low (unique) | Medium (.com typos) |
The .io Advantage
- ✓ Tech credibility: Developers immediately recognize and trust .io
- ✓ No typo confusion: Nobody types .io by accident
- ✓ Clear niche: Signals "we're a tech company"
- ✓ Good availability: More options than .com
⚠️ .io Concerns
- • Ethical debate: Controversy around British Indian Ocean Territory's history
- • Higher price: ~$45-60/year vs $25-35 for .co
- • Non-tech confusion: General audiences may not recognize it
The .co Advantage
- ✓ Company connotation: Naturally reads as "company"
- ✓ Broader appeal: Works for any business type
- ✓ Lower cost: ~$25-35/year
- ✓ Twitter uses it: t.co legitimized the extension
⚠️ .co Concerns
- • Typo risk: Users may accidentally type .com
- • When speaking: "Dot C-O" can sound like .com
- • Traffic leakage: Some visitors will end up at the .com version
Famous Examples
.io Sites
- codepen.io
- socket.io
- atom.io (was)
- keybase.io
- ngrok.io
.co Sites
- twitter.co (t.co)
- angel.co
- 500.co
- vine.co (was)
- overstock.co
Note: Many of these eventually acquired or redirected from their .com equivalents.
Which Should You Choose?
Choose .io If:
- • Your target audience is developers/tech
- • You're building a dev tool, API, or SaaS
- • You want to signal tech credibility
- • Budget allows the higher price
Choose .co If:
- • Your audience is mainstream/B2C
- • You want something more universal
- • Budget is a concern
- • You can acquire the .com later (to prevent typo issues)
The Bottom Line
Both are legitimate .com alternatives. .io has become the de facto tech startup TLD, while .co works for broader audiences. Neither will hurt your SEO.
Pro tip: If you go with .co, try to secure the .com too—even if it's just to redirect.