What’s actually changing
Cloudflare’s changelog states the change directly:
“The
foundation_dnsboolean is deprecated in the DNS settings endpoints for zone settings and account defaults”
Foundation DNS itself, Cloudflare’s enterprise-grade authoritative DNS offering enabled via "foundation_dns": true on the DNS settings endpoint, isn’t described as being discontinued. What’s deprecated is specifically this boolean field on the /zones/{zone_id}/dns_settings and /accounts/{account_id}/dns_settings endpoints, published and made effective the same day, 2026-07-27, with a longer runway before removal, 2026-11-23.
Don't guess the replacement field name
Cloudflare’s own changelog entry for this specific deprecation doesn’t name an exact successor field. Rather than assume a plausible-sounding replacement, pull the current DNS settings API reference directly before updating automation, and confirm the field name against a real API response, not a guess.
Structural Comparison Matrix
| Operational Aspect | Before 2026-11-23 | After 2026-11-23 |
|---|---|---|
foundation_dns field | Read/write, controls Foundation DNS state | No longer honored |
| Endpoints affected | /zones/{zone_id}/dns_settings, /accounts/{account_id}/dns_settings | Same endpoints, different accepted fields |
| Foundation DNS itself | Available | Still available, through a different field |
Fix it: audit before the field goes silent
The real risk here isn’t a thrown error. A script that PATCHes foundation_dns and checks only the HTTP status code, not the actual resulting DNS settings state, may keep reporting success on a field the API silently stops honoring, while Foundation DNS quietly stops being toggled the way the automation expects.
curl -X GET \
"https://api.cloudflare.com/client/v4/zones/<zone_id>/dns_settings" \
-H "Authorization: Bearer <api_token>"grep -rn "foundation_dns" --include="*.tf" --include="*.sh" --include="*.mjs" .Run the audit now, confirm the current API response shape against the live DNS settings docs, and update automation to match, rather than waiting for a silent no-op to surface as a support ticket in November.
Confirmed version
Sourced from Cloudflare’s official changelog, published 2026-07-27, deprecation effective the same day, end of life 2026-11-23. The exact replacement field name wasn’t found in this deprecation’s own changelog text; verify against the live DNS settings API reference before updating automation. Browse more posts like this in the Data Automation archive.
