Some applications and services provide integration through custom DNS records (usually TXT).
- **ATProtocol**: `TXT` record of name `_proto` with value `did={did:plc identifier}`
- **Discord**: `TXT` record of name `_discord` with value `dh={random string}`
- **GitHub Pages**: `TXT` record of name `_github-pages-challenge-{username}` with value `{random string}`
- **Google Workspaces**: The following records (last time I configured):
  - `MX` record of name `{domain}` with value `alt4.aspmx.l.google.com`
  - `MX` record of name `{domain}` with value `alt3.aspmx.l.google.com`
  - `MX` record of name `{domain}` with value `alt2.aspmx.l.google.com`
  - `MX` record of name `{domain}` with value `alt1.aspmx.l.google.com`
  - `TXT` record of name `google._domainkey` with value `v={value}; k={value}; p={value}` (enforces DKIM, [DomainKeys Identified Mail](https://www.cloudflare.com/learning/dns/dns-records/dns-dkim-record/))
    - `v`: version (DKIM1)
    - `k`: key type (RSA)
    - `p`: public key
  - `TXT` record of name `{domain}` with value `"v=spf1 include:_spf.google.com ~all"` (enforces SPF, [Sender Policy Framework](https://www.cloudflare.com/learning/dns/dns-records/dns-spf-record/))