Your First Domain Setup (Onamae.com x Vercel)

What You’ll Do

Connect a domain you own on Onamae.com (e.g., example.com) to a site deployed on Vercel.

When you’re done, your site will be accessible at a custom URL like my-site.example.com.

Background: How Domains Work

Let’s understand why this setup is needed in the first place.

User visits my-site.example.com
    |
    v
"Who manages example.com?"
    |
    v
Ask the nameserver (Onamae.com's DNS)
    |
    v
"my-site should go to Vercel" (= DNS record)
    |
    v
Arrives at Vercel's server → site loads

• Nameserver = the place that manages the domain’s “phone book”
• DNS record = an entry in the phone book (“this name → send to this address”)
• CNAME record = a type of DNS record that says “forward this subdomain to another address”

So there are really just two things to do:

1. Vercel side: Declare “I want to use this domain”
2. Onamae.com side: Tell DNS “send that domain to Vercel”

Key Terms

Term	Meaning	Example
Root domain	The domain you purchased	example.com
Subdomain	A name added before the root	my-site.example.com
Nameserver	Where DNS queries go	01.dnsv.jp (Onamae.com)
CNAME	A “forward to here” DNS record	my-site → Vercel

Subdomains don’t require purchasing another domain — you can create as many as you want for free.

Step 1: Add the Domain in Vercel

1. Log in to the Vercel dashboard
2. Select your project
3. Go to Settings → Domains
4. Enter your desired domain (e.g., my-site.example.com)
5. Click Add
6. Select Connect to an environment → choose Production
7. Click Save

You’ll see “Invalid Configuration” in red — this is normal. It will resolve after you complete the DNS setup below.

Note the Value Vercel Shows

After adding the domain, Vercel displays the DNS configuration values:

Field	Example
Type	CNAME
Name	my-site
Value	xxxxxx.vercel-dns-017.com.

Copy this Value — you’ll need it in the next step.

Step 2: Set Up Nameservers on Onamae.com

To use Onamae.com’s DNS record feature, the nameservers must point to Onamae.com’s own DNS.

If This Is Your First Time Using DNS Records

After registering a DNS record, Onamae.com may send an email saying:

To activate the DNS records you configured, you need to set the nameservers to the following.

If so, you need to change the nameservers.

1. Log in to Onamae.com Navi
2. Go to Domain Settings → Nameserver Change
3. Enter the following:

Field	Value
Nameserver 1	01.dnsv.jp
Nameserver 2	02.dnsv.jp

4. Save

Warning: If you’re already using this domain for a website or email, changing nameservers will affect those services. If nothing else is using it, you’re fine.

Step 3: Add the DNS Record on Onamae.com

1. Log in to Onamae.com Navi
2. Go to Domain Settings → DNS Settings → Use DNS Record Settings
3. Add the following record:

Hostname	TYPE	VALUE	TTL
my-site	CNAME	Paste the Value from Vercel exactly	Leave default

4. Save

If the VALUE ends with a dot (.), include the dot when pasting.

Step 4: Verify It Works

DNS propagation can take anywhere from a few minutes to several hours.

How to check:

• In Vercel’s Settings → Domains, the “Invalid Configuration” warning disappears
• Visit my-site.example.com in your browser and see your site

SSL certificates (https) are automatically issued by Vercel — no extra setup needed.

FAQ

Q: Do I need to buy a domain?

Not if you’re using a subdomain. If you already own example.com, you can create blog.example.com or app.example.com for free.

Q: What happens to the xxx.vercel.app URL?

It still works even after adding a custom domain. If you set the custom domain as the Primary Domain in Vercel’s Domains settings, visitors to .vercel.app will be redirected to your custom domain.

Q: Hyphens or underscores in the domain name?

Use hyphens (-).

Aspect	Hyphen -	Underscore _
Google treats it as	Word separator	Single word
URL convention	Standard	Rare
Typing ease	No Shift key	Requires Shift

Hyphens are recommended for SEO.

Q: I set it up but the site doesn’t load

• Wait for DNS propagation (up to a few hours)
• Verify you copied Vercel’s Value correctly
• Confirm nameservers are set to 01.dnsv.jp / 02.dnsv.jp
• Clear your browser cache and try again

Next Steps

• Getting Started with AI Coding Tools — Start building your own site
• Writing a CLAUDE.md — Teach AI your project’s rules