# IPv6 normalize

`ipv6-normalize` · version 1.0.0 · URLs & IP addresses · free, no key needed

Normalize any valid textual IPv6 address directly into its RFC 5952 canonical compressed string.

**Use when you need to: ipv6 normalize · canonicalize ipv6 address · ipv6 compress.**

## Supported

- ipv6 normalize
- canonicalize ipv6 address
- ipv6 compress

## Not supported

- zone/scope IDs
- preserving an IPv4-embedded tail in the output (it is rendered in hex)

## Behavior

- address accepts any RFC 4291 textual form, exactly as ipv6-parse does.
- address (output) is the RFC 5952 canonical string: lowercase hex, no leading zeros per group, and the leftmost longest run of two or more all-zero groups compressed once as "::".
- Equivalent to ipv6-format(ipv6-parse(address).hextets) in one call.

## Input

- `address` (string, required): max length 45

## Output

- `address` (string, required): max length 45

## Limits

- max address length: 45

## Example

Request input:

```json
{
  "address": "2001:0DB8:0000:0000:0000:0000:0000:0001"
}
```

Response:

```json
{
  "result": {
    "address": "2001:db8::1"
  }
}
```

## How to call it

### MCP

Connect `https://computefirst.net/mcp` ([setup](/docs#connect)), then call `execute` with:

```json
{
  "id": "ipv6-normalize",
  "version": "1.0.0",
  "input": {
    "address": "2001:0DB8:0000:0000:0000:0000:0000:0001"
  }
}
```

### HTTP (no key)

```sh
curl -X POST https://computefirst.net/v1/tools/ipv6-normalize/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"address":"2001:0DB8:0000:0000:0000:0000:0000:0001"}'
```

The machine-readable contract is at [/v1/tools/ipv6-normalize/versions/1.0.0](/v1/tools/ipv6-normalize/versions/1.0.0).

### CLI

```sh
node cli.mjs run ipv6-normalize 1.0.0 --input input.json --base-url https://computefirst.net
```

Get the client at [/clients/cli/](/clients/cli/).

## Related tools

- [IPv6 address classify](/tools/ipv6-address-classify): Classify an IPv6 address against the static IANA IPv6 special-purpose address registry.
- [IPv6 address compare](/tools/ipv6-address-compare): Compare two IPv6 addresses by their numeric 128-bit value.
- [IPv6 address distance](/tools/ipv6-address-distance): Compute the signed integer distance between two IPv6 addresses (address_b minus address_a).
- [IPv6 address offset](/tools/ipv6-address-offset): Add a signed integer offset to an IPv6 address, throwing if the result leaves the IPv6 address space.
- [IPv6 in CIDR](/tools/ipv6-in-cidr): Test whether an IPv6 address lies in a CIDR prefix whose host bits are zero.
- [IPv6 parse](/tools/ipv6-parse): Parse an IPv6 address (any RFC 4291 textual form) into its 8 hextets and a 128-bit integer string.