Incident Postmortem Template

Blameless learning framework capturing what happened, why, and how to prevent future incidents

TL;DR

A postmortem is a structured conversation for learning from incidents. Blameless postmortems focus on systems and processes, not people. The goal is to understand what happened, why the system failed, and what systemic improvements prevent recurrence. Conduct postmortems quickly while details are fresh.

Learning Objectives

After using this template, you will be able to:

Conduct blameless postmortems that focus on learning
Perform effective root cause analysis using 5 Whys
Identify systemic contributing factors
Create actionable follow-up items
Track and close action items systematically
Build a culture of continuous improvement

What Makes a Good Postmortem

Postmortem Template

1. Incident Summary

Example Summary: "Incident #2025-002 occurred on Feb 14, 2025 at 14:30 UTC. Payment processing service became unresponsive due to database connection pool exhaustion. Incident lasted 45 minutes (resolved 15:15 UTC). Approximately 2,000 payment transactions failed, affecting 500+ users. Impact: $12K revenue loss, reputational damage. Detected automatically at 14:30 by latency alerts. Response team engaged immediately."

2. Incident Timeline

Document what happened chronologically:

Timeline Example

Time (UTC)	Event
14:28	New code deployment completed (payment-service v2.4.0)
14:30	Database connection pool hits 100% utilization
14:30	Latency alert fires (p95 latency > 10 seconds)
14:31	Incident commander engaged, bridge started
14:32	Investigation begins: check metrics, logs, recent changes
14:35	Root cause identified: new code has N+1 query problem
14:40	Decision made to rollback to v2.3.0
14:42	Deployment team initiates rollback
14:46	Rollback completed, service recovering
14:50	Database connections normalize
14:55	Latency returns to baseline
15:00	Service fully operational, incident declared resolved
15:15	Incident commander closed bridge

Timeline Requirements
Entries for significant events (alerts, actions taken, changes made)
Include what was observed (metric values, errors, user complaints)
Include what actions were taken and by whom
Timeline clear enough for future readers to understand sequence of events

3. Root Cause Analysis (RCA)

Apply structured root cause analysis:

4. Contributing Factors

Identify systemic factors that enabled the failure:

Contributing Factors Example

Process Gaps:

No mandatory performance regression testing before production deployment
Load testing environment access limited and difficult to use
No automated performance testing in CI/CD pipeline
Code review process doesn't specifically check for database query patterns

Technical Gaps:

No query analysis tooling integrated into codebase
Database connection pool monitoring not alerted until exhausted
No graceful degradation when connection pool full
Slow-query logging not enabled in production database

Cultural:

Team under time pressure skipped load testing to meet deadline
Developers didn't know performance testing was critical for payment service
"Performance will be fine" assumption made without validation

Environmental:

Staging environment doesn't replicate production traffic volume
No canary deployment strategy to detect issues gradually
Blue-green deployment not available for rapid rollback

5. Action Items

Create specific, assignable action items to prevent recurrence:

Action Item Format
Why: How this prevents similar incidents
Who: Specific person or team assigned
When: Target date for completion
How to verify: How will we confirm completion?

Example Action Items:

ID	Action	Priority	Owner	Target Date	Status
A1	Implement automated load testing in CI/CD pipeline	P1	Platform Team	2025-03-15	In Progress
A2	Add query analysis tool to code review process	P1	Backend Team	2025-03-01	Not Started
A3	Enable slow-query logging in production database	P2	DBA	2025-02-21	Not Started
A4	Implement canary deployments for payment service	P2	Platform Team	2025-04-01	Not Started
A5	Document performance testing requirements for critical services	P3	Tech Lead	2025-03-01	Not Started

6. Lessons Learned

Document key insights from the incident:

What went well: What did we handle effectively?
What could be improved: What was difficult or slow?
What surprised us: What didn't we expect?
What we're changing: Specific action items

Example:

What Went Well:

Fast incident detection and alerting (2 minutes to alert)
Clear communication on war bridge
Quick decision to rollback vs. troubleshoot forward
Rollback process was smooth and fast (4 minutes)

What Could Be Improved:

RCA too late (performed a day after incident) while details fresh
No communication to affected customers until 30 minutes into incident
Root cause not obvious from initial metrics
Staging environment didn't catch this failure

What Surprised Us:

N+1 query issue didn't appear in unit or integration tests
New developer unfamiliar with performance patterns in this codebase
Load testing skipped without anyone objecting

7. Follow-Up Tracking

Action Item Status
Update status in postmortem monthly
Link to related tickets/PRs for transparency
Escalate overdue items for resolution
Verification
Verify action actually prevents the incident scenario
Close action items only when verified complete
Document what was learned from action item completion

Blameless Culture Principles

Blameless Postmortem Principles

Assume Good Intent: Assume everyone involved was doing their best with available information. Incidents happen because of system failures, not individual failures.

Focus on Systems, Not People: "Why did John push buggy code?" is blame. "Why did code review not catch N+1 queries?" is systemic. Ask about systems.

No Punishment for Incidents: Punishing incidents discourages transparency and honest postmortems. Punish negligence and ignoring safety practices, not incidents.

Everyone's a Learner: All roles contribute to incidents—from code review to deployment to monitoring. Everyone has something to learn.

Psychological Safety: Create environment where people can speak honestly about their mistakes, uncertainties, and observations. Without it, root causes stay hidden.

Common Postmortem Mistakes

Mistakes to Avoid

Blame the person: "Alice deployed bad code" doesn't fix systems. Ask why code review didn't catch it, why testing didn't catch it, why deployment allowed it.

Conducting postmortem too late: Waiting weeks to conduct postmortem loses details and context. Conduct within 24-48 hours while fresh.

Action items without owners: "We should improve monitoring" isn't actionable. "Sarah will implement alerting for X by Feb 28" is actionable.

Never following up on action items: Action items that aren't tracked and closed are theater. Make follow-up mandatory.

Using postmortem for punishment: If incidents become occasions for blame, people hide them. Transparency collapses.

Ignoring systemic causes: If you keep fixing symptoms instead of systems, you'll have incidents repeatedly.

Postmortem Workflow

Immediately After Incident
24-48 Hours Later
Ongoing

Stabilize the Service
- Resolve the immediate issue
- Restore functionality
- Monitor for stability
Document Timeline
- While events are fresh, record what happened
- Get details from all incident responders
- Record all times in UTC
Identify Obvious Actions
- Quick wins to prevent immediate recurrence
- Temporary mitigations if needed
- Schedule permanent fixes

Self-Check

After conducting postmortem, verify:

Timeline is complete and accurate with all timestamps in UTC
Root cause analysis goes to systemic level (not just immediate cause)
All action items are specific with assigned owners and target dates
Action items are tracked and updated regularly
Postmortem is shared with full team
There's clear follow-up process for action items
Learning is captured for future reference
No one was blamed for the incident

One Takeaway

The goal of a postmortem is not to prevent all incidents (impossible) but to learn from each incident so we don't repeat the same failures. Done right, postmortems make your systems more resilient over time.

Next Steps

Establish postmortem policy (when required, timeline, process)
Train team on blameless culture and RCA techniques
Create postmortem template and process documentation
Conduct postmortems soon after significant incidents (within 24-48 hours)
Track and verify action items with visible status tracking
Share postmortem summaries with entire organization

References

Site Reliability Engineering: Postmortems ↗️ - Google's SRE book on blameless postmortems
Etsy's Debriefing Facilitation Guide ↗️
Root Cause Analysis (5 Whys) ↗️
Incident Response Best Practices ↗️

Incident Postmortem Template

TL;DR​

Learning Objectives​

What Makes a Good Postmortem​

Postmortem Template​

1. Incident Summary​

2. Incident Timeline​

Timeline Example

3. Root Cause Analysis (RCA)​

4. Contributing Factors​

Contributing Factors Example

5. Action Items​

6. Lessons Learned​

7. Follow-Up Tracking​

Blameless Culture Principles​