# What Is the Timestamp TXT Record in is-a.dev? Purpose and Usage

> Discover the purpose of the timestamp TXT record in is-a.dev. Learn how this machine-readable marker helps track zone refresh times and ensures data accuracy.

- Repository: [is-a.dev/register](https://github.com/is-a-dev/register)
- Tags: deep-dive
- Published: 2026-03-09

---

**The `_zone-updated` TXT record is a Unix timestamp (in milliseconds) automatically injected into every DNS zone generation to provide a public, machine-readable marker of when the is-a.dev zone was last refreshed.**

The `is-a-dev/register` repository automates DNS management for thousands of developer subdomains. Within its DNS configuration pipeline, a special **timestamp TXT record** serves as a critical metadata signal. This record, named `_zone-updated`, is generated every time the zone file is rebuilt, offering transparency and operational utility for both maintainers and users.

## How the Timestamp TXT Record Works in is-a.dev

The record generation happens in the core DNS configuration script. In [`dnsconfig.js`](https://github.com/is-a-dev/register/blob/main/dnsconfig.js) at lines 146-148, the code appends a TXT record containing the current millisecond timestamp:

```js
// dnsconfig.js – line 146‑148
// Append a TXT record that stores the current timestamp (ms since epoch)
records.push(TXT("_zone-updated", "\"" + Date.now().toString() + "\""));

```

`Date.now()` captures the exact moment of zone compilation. Because this script runs whenever pull requests are merged or domains are modified, the **timestamp TXT record** always reflects the most recent zone build time.

## Why is-a.dev Uses a Timestamp TXT Record

The `_zone-updated` record serves four primary operational functions according to the `is-a-dev/register` source code:

- **Cache busting**: Cloudflare and downstream resolvers cache DNS responses. The changing timestamp forces recognition of zone updates, helping external tools detect fresh configurations without waiting for TTL expiration.
- **Change detection**: Users can query the record to verify that recent pull requests have been deployed. A simple DNS lookup reveals exactly when the zone was last regenerated.
- **Audit trail**: The public timestamp provides a lightweight, tamper-evident log of service activity. It records configuration updates without exposing internal identifiers or sensitive metadata.
- **Automation**: CI pipelines and monitoring scripts can poll `_zone-updated` to trigger downstream actions, such as cache invalidation or deployment notifications, based on the exact zone build time.

## Querying and Using the is-a.dev Timestamp Record

You can interact with this record programmatically or via command-line tools.

### Command Line Query with dig

Retrieve the current timestamp directly from DNS:

```bash

# Using dig (or any DNS lookup tool)

dig TXT _zone-updated.is-a.dev +short

# Example output:

"1710189234567"

```

### Converting the Timestamp

The returned value is a Unix timestamp in milliseconds. Convert it to human-readable format:

```bash

# Bash conversion

ts=$(dig TXT _zone-updated.is-a.dev +short | tr -d '"')
date -d @"$((ts/1000))"

# => Fri Mar 10 14:33:54 UTC 2026

```

### Programmatic Access in Node.js

Automate monitoring by reading the record in your applications:

```js
const { execSync } = require('child_process');

function getZoneUpdate() {
  const raw = execSync('dig +short TXT _zone-updated.is-a.dev')
    .toString()
    .trim()
    .replace(/"/g, '');
  const ms = Number(raw);
  return new Date(ms);
}

console.log('Zone last updated at:', getZoneUpdate().toISOString());

```

## Summary

- The **timestamp TXT record** (`_zone-updated`) is automatically generated in [`dnsconfig.js`](https://github.com/is-a-dev/register/blob/main/dnsconfig.js) (lines 146-148) using `Date.now()`.
- It provides a public Unix timestamp in milliseconds indicating the exact moment the is-a.dev DNS zone was last rebuilt.
- The record enables **cache busting**, **change detection**, and **automation** for users and maintainers monitoring the service.
- You can query it via standard DNS tools like `dig` to verify deployment timing or integrate it into monitoring scripts.

## Frequently Asked Questions

### What is the exact name of the timestamp TXT record in is-a.dev?

The record is named `_zone-updated`. It is a TXT record placed at the apex of the `is-a.dev` zone, meaning you query it as `_zone-updated.is-a.dev`.

### How often does the is-a.dev timestamp TXT record update?

The record updates every time the DNS zone is regenerated. This occurs whenever a pull request is merged, a domain is added or removed, or any DNS record changes are processed by the `is-a-dev/register` repository's automation pipeline.

### Can I rely on the _zone-updated record for monitoring deployments?

Yes. Because the value changes only when the zone file is rebuilt, polling `_zone-updated` via DNS queries provides a reliable signal that new configurations have propagated. You can compare timestamps to detect when your specific subdomain changes have taken effect.

### Does the timestamp TXT record affect DNS resolution for my subdomain?

No. The `_zone-updated` record is purely informational metadata. It does not impact how resolvers handle your A, CNAME, MX, or other functional records. It serves only as a diagnostic and monitoring tool for the zone's generation time.