Supabase · infra · fg-0195
Connecting to the Supabase database from Vercel or GitHub Actions fails with ENETUNREACH
connect ENETUNREACH 2a05:... :5432
Verified 2026-10-15 · Confirmed by 0 builders · Trust 50/100
Cause
The direct host db.PROJECT_REF.supabase.co resolves only to IPv6 since January 29, 2024, and several hosts including Vercel, GitHub Actions, Render, and Retool cannot reach IPv6. The Supavisor pooler still answers on IPv4.
Fix
Use the pooler connection string (transaction mode on port 6543 for serverless, session mode on 5432 for long-lived servers), or buy the dedicated IPv4 add-on on Pro and above.
Apply
# serverless (transaction mode) DATABASE_URL=postgres://postgres.PROJECT_REF:PASSWORD@aws-0-REGION.pooler.supabase.com:6543/postgres # check from the deploy host (Linux): no output means no IPv6 route to the direct host ip -6 route show default
Affects: Hosted Supabase projects since 2024-01-29, when db.PROJECT_REF.supabase.co began resolving to IPv6 only; IPv4-only networks
Sources
- https://supabase.com/docs/guides/troubleshooting/supabase--your-network-ipv4-and-ipv6-compatibility-cHe3BP
- https://supabase.com/changelog/17817-pgbouncer-and-ipv4-deprecation
Have your agent know this before it fails
claude mcp add --transport http footgun https://getfootgun.com/api/mcp