Build vs Buy: Choosing an Audit Trail Service
Every organisation needs audit trails for security, compliance, and operational visibility. The question is: should you build this capability yourself or use a dedicated audit trail service? This decision has significant implications for your team's time, your system's architecture, and your ability to meet compliance requirements. Let's explore the factors to consider.
The Core Requirements
Before deciding, understand what you actually need:
Functional Requirements
- Event Logging: Capture events from your applications
- Immutable Storage: Ensure logs can't be modified
- Querying: Search and filter events by various criteria
- Retention: Store logs for required periods (often years)
- Export: Generate reports and export data for auditors
- Monitoring: Alert on suspicious patterns
- Integration: Easy integration with your applications
Non-Functional Requirements
- Performance: Handle high event volumes without impacting application performance
- Reliability: Never lose events, even during failures
- Security: Protect logs from unauthorised access
- Scalability: Grow with your organisation
- Compliance: Meet SOC 2, ISO 27001, GDPR, HIPAA requirements
Building In-House: The Reality
Building a production-grade audit trail system is more complex than it might seem:
What You Need to Build
Event Ingestion API: A service that accepts events from your applications:
- REST API or message queue interface
- Authentication and authorisation
- Rate limiting and throttling
- Validation and normalisation
- High availability and load balancing
Storage System: Immutable, scalable storage:
- Hash chain implementation for tamper detection
- Efficient indexing for querying
- Retention management
- Backup and disaster recovery
- Multi-region support (for compliance)
Query Interface: API for retrieving events:
- Complex query capabilities
- Pagination and filtering
- Performance optimisation
- Access control
Monitoring and Alerting: Detect suspicious activity:
- Real-time event processing
- Pattern detection
- Alerting infrastructure
- Dashboard and visualisation
Compliance Features: Meet regulatory requirements:
- Tamper-evident storage
- Audit log of audit logs
- Retention policy enforcement
- Compliance reporting
The Hidden Costs
Development Time: Building all of this takes significant engineering time:
- Initial development: 3-6 months for a small team
- Ongoing maintenance: 20-30% of a developer's time
- Bug fixes and improvements: Continuous
Operational Overhead: Running the system requires:
- Infrastructure costs (servers, storage, networking)
- Monitoring and alerting
- Backup and disaster recovery
- Security updates and patches
- Scaling and performance tuning
Expertise Required: You need expertise in:
- Cryptography (hash chains, digital signatures)
- Distributed systems
- Compliance requirements (SOC 2, GDPR, etc.)
- High-performance storage systems
- Security best practices
Opportunity Cost: Time spent building audit trails is time not spent on:
- Core product features
- Customer-facing improvements
- Competitive differentiation
Common Pitfalls
Underestimating Complexity: Many teams underestimate how complex audit trails are:
- "We'll just log to a database" (doesn't meet immutability requirements)
- "We'll add it later" (much harder to retrofit)
- "It's just logging" (compliance requirements are strict)
Performance Issues: Audit logging can impact application performance:
- Synchronous logging blocks requests
- Storage becomes a bottleneck
- Query performance degrades with scale
Compliance Gaps: Missing requirements:
- Not implementing hash chains (can't prove immutability)
- Insufficient retention policies
- Missing access controls
- No audit log of audit logs
Maintenance Burden: Ongoing maintenance is significant:
- Scaling issues
- Performance optimisation
- Security updates
- Compliance changes
Buying a Service: The Benefits
Using a dedicated audit trail service like HyreLog offers several advantages:
Focus on Core Business
Your engineering team can focus on building your core product instead of infrastructure:
- Faster time to market for features
- Better product quality
- More innovation
Expertise and Best Practices
Dedicated services have deep expertise:
- Cryptography and security
- Compliance requirements
- Performance optimisation
- Best practices from serving many customers
Faster Implementation
Get audit trails working quickly:
- Simple API integration
- Pre-built compliance features
- Immediate availability
- No infrastructure setup
Lower Total Cost
While there's a subscription cost, total cost is often lower:
- No development time
- No infrastructure management
- No maintenance overhead
- Predictable pricing
Built-in Compliance
Services are designed for compliance:
- SOC 2, ISO 27001 certified
- GDPR compliant
- Hash chains for immutability
- Proper retention policies
- Compliance reporting
Reliability and Scale
Services are built for reliability and scale:
- High availability
- Automatic scaling
- Disaster recovery
- Performance optimisation
When to Build
There are situations where building makes sense:
Unique Requirements
If you have very specific requirements that services don't support:
- Unusual compliance requirements
- Specific integration needs
- Custom data formats
- Specialised use cases
Existing Infrastructure
If you already have infrastructure that can be leveraged:
- Existing event streaming infrastructure
- Compliance systems already in place
- Security tools that include audit logging
- Data platforms with audit capabilities
Large Scale
If you're operating at very large scale:
- Millions of events per second
- Petabytes of log data
- Custom performance requirements
- Cost optimisation at extreme scale
Security Concerns
If you have strict data residency or security requirements:
- Data must stay in specific regions
- Cannot use third-party services
- Government or military contracts
- Highly regulated industries
When to Buy
Buying makes sense when:
Speed to Market Matters
You need audit trails quickly:
- Compliance deadline approaching
- Customer requirement
- Security incident response
- Competitive pressure
Limited Engineering Resources
Your team is focused on core product:
- Small engineering team
- Limited infrastructure expertise
- Need to move fast
- Can't afford distraction
Compliance is Critical
You need to meet strict compliance requirements:
- SOC 2 certification needed
- GDPR compliance required
- Industry regulations
- Customer audits
Cost Efficiency Matters
Total cost of ownership is important:
- Limited budget
- Need predictable costs
- Can't afford development time
- Want to avoid operational overhead
Evaluation Criteria
If you're evaluating audit trail services, consider:
Functional Capabilities
- Event ingestion API (REST, SDKs, webhooks)
- Query and search capabilities
- Export and reporting
- Integration options
- Monitoring and alerting
Security and Compliance
- SOC 2, ISO 27001 certifications
- Hash chains for immutability
- Encryption at rest and in transit
- Access controls
- Data residency options
Performance and Reliability
- Event ingestion latency
- Query performance
- Availability SLA
- Scalability limits
- Disaster recovery
Developer Experience
- Quality of SDKs and documentation
- Ease of integration
- Support and community
- API design
- Examples and tutorials
Pricing
- Pricing model (per event, per GB, flat fee)
- Predictability
- Cost at your scale
- Hidden costs
- Value for money
Making the Decision
Here's a framework for making the decision:
Score Your Requirements
Rate each requirement (1-5):
- Criticality: How important is this requirement?
- Complexity: How hard is it to build?
- Uniqueness: How unique are your needs?
Evaluate Build Option
- Development Time: How long to build?
- Ongoing Maintenance: What's the maintenance burden?
- Total Cost: Development + operations + opportunity cost
- Risk: What if you get it wrong?
Evaluate Buy Option
- Feature Fit: Does the service meet your needs?
- Integration Effort: How easy to integrate?
- Total Cost: Subscription + integration + migration
- Risk: What if the service fails or changes?
Consider Hybrid Approaches
You might not need to choose exclusively:
- Core Events: Use a service for critical compliance events
- Operational Events: Build simple logging for operational events
- Gradual Migration: Start with a service, build later if needed
Common Mistakes
Over-Engineering
Building more than you need:
- Complex features you'll never use
- Premature optimisation
- Over-architecting for scale you don't have
Under-Engineering
Building less than you need:
- Missing compliance requirements
- Poor performance
- Insufficient reliability
- Security gaps
Ignoring Total Cost
Focusing only on subscription cost:
- Not considering development time
- Ignoring operational overhead
- Missing opportunity cost
- Underestimating maintenance
Vendor Lock-in Concerns
Worrying too much about lock-in:
- Audit logs are exportable
- Standards-based APIs
- Can migrate if needed
- Premature optimisation
Recommendation
For most organisations, buying is the right choice:
- Faster: Get audit trails working in days, not months
- Better: Services have expertise you don't
- Cheaper: Total cost is usually lower
- Lower Risk: Proven solutions vs. building from scratch
Build only if:
- You have very unique requirements
- You're operating at extreme scale
- You have strict data residency requirements
- You have excess engineering capacity
Conclusion
The build vs. buy decision for audit trails is significant. While building gives you full control, it requires substantial engineering effort, ongoing maintenance, and deep expertise. Buying a service like HyreLog gets you production-ready audit trails quickly, with built-in compliance and best practices.
Most organisations should buy. The time, cost, and risk savings usually outweigh the benefits of building yourself. Focus your engineering team on your core product, and let dedicated services handle infrastructure like audit trails.
If you're evaluating services, focus on functional capabilities, security and compliance, performance, developer experience, and pricing. And remember: you can always build later if your needs change, but you can't get back the time spent building something you could have bought.
