Merge Subs & Domains

Merge subs with single or multiple domains

Single Domain One sub per domain

Multiple Domains One sub for all domains

Single Domain

One subdomain per domain

sub1 ─ google.com → sub1.google.com
sub2 ─ mdtools.one → sub2.mdtools.one
sub3 ─ example.com → sub3.example.com

Multiple Domains

One subdomain for all domains

sub1
├─ google.com → sub1.google.com
├─ mdtools.one → sub1.mdtools.one
└─ example.com → sub1.example.com

sub2
├─ google.com → sub2.google.com
├─ mdtools.one → sub2.mdtools.one
└─ example.com → sub2.example.com

Input lines subs: 0 | Input lines domains: 0 | Output lines: 0

Merge Subs & Domains

Instantly build full hostnames by combining sub-domain segments with one or more domain names. Paste your sub-domain and domain lists, then generate every possible hostname combination directly in your browser — no uploads or installations required.

🔗 How do I merge sub-domains and domains?

To merge sub-domains with domains, paste your list of sub-domain parts into the first input box and your list of main domains into the second box. Then click “Merge Subs & Domains” to generate full hostnames like `sub1.example.com`.

🧱 What are the steps to generate merged hostnames?

Paste your list of sub-domains (one per line) into the first box.
Paste your list of domains (one per line) into the second box.
Click the “Merge Subs & Domains” button to process the input.
Review the generated hostnames and counts for input and output.
Copy or download your merged list of full hostnames.

⚡ Why use a Merge Subs & Domains tool?

This tool automates what would otherwise be a manual and time-consuming task: building full hostnames by combining many sub-domain prefixes with one or more domains. Save time and reduce errors with instant output.

Automatic hostname building: Get full hostnames quickly.
Saves time: Avoid manual concatenation for many entries.
Accurate output: Each sub-domain is correctly paired with each domain.

💡 Tips for best results

To ensure accurate merged output:

Place each sub-domain and domain on its own line in their respective input boxes.
Use the Clean Sub-domains tool beforehand to remove duplicates.
Use Sort Text Lines to organize data before merging.
Check the output counts to confirm you generated the expected number of hostnames.

❓ Frequently Asked Questions

What does the Merge Subs & Domains tool do?

It takes two lists — sub-domain prefixes and main domains — and creates all possible full hostname combinations, such as `mail.example.com`.

How do I merge sub-domains and domains online?

Paste your sub-domain list and your domain list into the two input fields, then click “Merge Subs & Domains.” You’ll instantly see the merged results with counts of input and output lines.

Is this tool safe to use?

Yes. All processing happens locally in your browser — your data is never uploaded or stored externally.

What format works best for merging?

Plain text with one sub-domain or domain per line ensures the most accurate merging.