Step-by-step incident response for Vercel deployment failures, function errors, and platform outages. Covers rapid triage, instant rollback, communication templates, and postmortem procedures.
# 1. Check if it's a Vercel platform issue
curl -s "https://www.vercel-status.com/api/v2/summary.json" \
| jq '.status.description, [.components[] | select(.status != "operational") | {name, status}]'
# 2. Check current production deployment status
vercel ls --prod
vercel inspect $(vercel ls --prod --json | jq -r '.[0].url')
# 3. Check recent deployments — did a deploy just happen?
curl -s -H "Authorization: Bearer $VERCEL_TOKEN" \
"https://api.vercel.com/v6/deployments?target=production&limit=5&projectId=prj_xxx" \
| jq '.deployments[] | {uid, state, createdAt: (.createdAt/1000 | todate), url}'
# 4. Check function logs for errors
vercel logs $(vercel ls --prod --json | jq -r '.[0].url') --level=error --limit=20
Is vercel-status.com showing an incident?
├── YES → Vercel platform issue
│ ├── Subscribe to updates on status page
│ ├── Post internal status: "Vercel platform incident — monitoring"
│ └── No action needed from us — wait for Vercel resolution
│
└── NO → Issue is in our deployment
├── Did a deployment happen in the last 30 minutes?
│ ├── YES → Likely deployment regression
│ │ └── ROLLBACK immediately (Step 3)
│ └── NO → Application-level issue
│ ├── Check function logs for new errors
│ ├── Check external dependency status (DB, APIs)
│ └── Investigate and hotfix (Step 4)
│
└── Is the issue region-specific?
├── YES → Check function regions, possible edge issue
└── NO → Global issue, check code and env vars
# Option A: Rollback to previous production deployment (fastest)
vercel rollback
# This instantly swaps production traffic — no rebuild needed
# Option B: Rollback to a specific known-good deployment
vercel rollback dpl_xxxxxxxxxxxx
# Option C: Via API (for automation/PagerDuty integration)
curl -X POST "https://api.vercel.com/v9/projects/my-app/promote" \
-H "Authorization: Bearer $VERCEL_TOKEN" \
-H "Content-Type: application/json" \
-d '{"deploymentId": "dpl_known_good_id"}'
# Verify rollback succeeded
vercel ls --prod
curl -s https://yourdomain.com/api/health | jq .
# Collect evidence while it's fresh
mkdir incident-$(date +%Y%m%d)
cd incident-$(date +%Y%m%d)
# Function logs around the incident time
vercel logs https://yourdomain.com --limit=200 > function-logs.txt
# Deployment diff — what changed?
curl -s -H "Authorization: Bearer $VERCEL_TOKEN" \
"https://api.vercel.com/v13/deployments/dpl_broken" \
| jq '.meta' > broken-deployment-meta.json
# Compare env vars between working and broken deployments
vercel env ls > env-vars.txt
# Check git diff between last good and broken commit
git log --oneline -10
git diff dpl_good_commit..dpl_broken_commit -- api/ src/
// vercel.json — temporary maintenance mode via rewrite
{
"rewrites": [
{
"source": "/((?!_next|api/health).*)",
"destination": "/maintenance.html"
}
]
}
<!-- public/maintenance.html -->
<!DOCTYPE html>
<html>
<head><title>Maintenance</title></head>
<body>
<h1>We'll be right back</h1>
<p>We're performing scheduled maintenance. Please check back shortly.</p>
</body>
</html>
Internal — Slack (Incident Start)
:rotating_light: INCIDENT: [Project Name] production issue detected
Status: Investigating
Impact: [Description of user impact]
Start time: [UTC timestamp]
On-call: @[engineer]
Thread: replies here
Internal — Slack (Mitigation)
:white_check_mark: MITIGATED: [Project Name]
Action: Rolled back to deployment dpl_xxx
Impact duration: [X minutes]
Root cause: [Brief description]
Postmortem: [link] scheduled for [date]
External — Status Page
Title: Degraded performance on [service]
Body: We are investigating reports of [issue]. Some users may experience
[impact]. Our team is actively working on a resolution.
Update: The issue has been resolved. [Brief root cause].
# Incident Postmortem: [Title]
## Summary
- Duration: [start] to [end] ([X minutes])
- Impact: [users/requests affected]
- Severity: [P1/P2/P3]
## Timeline (UTC)
- HH:MM — [event]
- HH:MM — Alert fired
- HH:MM — On-call acknowledged
- HH:MM — Root cause identified
- HH:MM — Rollback executed
- HH:MM — Service restored
## Root Cause
[What broke and why]
## Resolution
[What was done to fix it]
## Action Items
- [ ] [Preventive action] — Owner: @xxx — Due: [date]
- [ ] [Detection improvement] — Owner: @xxx — Due: [date]
- [ ] [Process improvement] — Owner: @xxx — Due: [date]
| Severity | Definition | Response Time | Rollback? |
|---|---|---|---|
| P1 | Production down, all users affected | < 5 min | Immediate |
| P2 | Degraded, some users affected | < 15 min | If not fixable in 30 min |
| P3 | Minor issue, workaround exists | < 1 hour | No |
| P4 | Cosmetic or non-urgent | Next business day | No |
| Scenario | Action |
|---|---|
| Vercel status page shows incident | Monitor, communicate, no deployment changes |
vercel rollback fails |
Use API promotion: POST to /v9/projects/.../promote |
| Rollback deployment also broken | Deploy from a known-good git tag |
| Cannot access Vercel dashboard | Use CLI with saved VERCEL_TOKEN |
| Log retention expired | Check external log drain provider |
For data handling and compliance, see vercel-data-handling.