A template for a cloud-based product technical requirements document should organize requirements into five categories that map directly to cloud product failure modes: availability and SLA requirements (what uptime do we promise?), scalability requirements (how does the system behave under 10x load?), security and compliance requirements (what data protection laws apply?), integration requirements (what external systems must we connect to?), and data residency requirements (where must customer data live?).
Cloud-native TRDs that skip any of these five categories create the same failure: the product launches and then fails in a way that was entirely predictable had the category been specified. A product with no documented scalability requirements is a product that will fail under the first viral traffic spike.
TRD Template Structure
Section 1: Availability and SLA Requirements
Target availability: [e.g., 99.9% uptime = 8.7 hours downtime per year; 99.95% = 4.4 hours; 99.99% = 52 minutes]
Deployment model: [Multi-region active-active / Multi-region active-passive / Single-region multi-AZ]
Recovery objectives:
- Recovery Time Objective (RTO): [Maximum acceptable downtime after an incident] — e.g., 4 hours
- Recovery Point Objective (RPO): [Maximum acceptable data loss measured in time] — e.g., 1 hour
Maintenance windows: [When can planned maintenance occur without SLA impact?]
Monitoring and alerting requirements:
- Latency SLA: [P50 / P95 / P99 response time targets for each API endpoint or service]
- Error rate SLA: [Acceptable error rate threshold, e.g., <0.1% 5xx errors]
Section 2: Scalability Requirements
Peak load specification:
- Expected baseline load: [requests per second or concurrent users]
- Expected peak load: [3x / 10x / 100x baseline] during [expected peak event type]
- Load ramp profile: [Does load spike suddenly (viral event) or grow linearly (business day)?]
Auto-scaling requirements:
- Scale-out trigger: [CPU > 70%, memory > 80%, request queue depth > N]
- Scale-out time: [Time from trigger to fully provisioned new instances]
- Scale-in safety period: [Minimum time before scaling in after a scale-out event]
Database scalability:
- Expected read/write ratio
- Expected peak QPS for database layer
- Read replica requirements
- Sharding or partitioning strategy (if applicable)
According to Lenny Rachitsky's writing on cloud product architecture, the scalability requirements that are most often under-specified are the scale-out time and the database read/write ratio — products that can scale compute in 3 minutes but cannot scale their database in the same window fail under spike traffic even with auto-scaling enabled.
Section 3: Security and Compliance Requirements
Data classification:
| Data Type | Classification | Storage Requirements | Retention Period | |---|---|---|---| | PII (name, email) | Sensitive | Encrypted at rest (AES-256) | Per privacy policy | | Financial data | Highly sensitive | Encrypted at rest and in transit, tokenized | 7 years (SOX) | | Usage analytics | Internal | Standard | 2 years |
Authentication requirements:
- SSO protocol: [SAML 2.0 / OIDC / OAuth 2.0]
- MFA: [Required for admin roles / All users / Optional]
- Session timeout: [Idle timeout and absolute timeout]
Compliance frameworks that apply:
- [ ] SOC 2 Type II
- [ ] GDPR (if serving EU customers)
- [ ] HIPAA (if processing PHI)
- [ ] PCI DSS (if processing payment card data)
- [ ] FedRAMP (if serving US federal agencies)
Section 4: Integration Requirements
For each external integration, document:
| Integration | Protocol | Authentication | Rate Limit | Failure Handling | |---|---|---|---|---| | [System A] | REST / GraphQL / Webhook | OAuth 2.0 / API key | N req/min | Retry with exponential backoff, dead letter queue | | [System B] | | | | |
Data synchronization requirements:
- Sync frequency: [Real-time / Near-real-time / Batch]
- Conflict resolution: [Last write wins / Source of truth hierarchy]
- Idempotency requirements: [Are duplicate events tolerated or must they be deduplicated?]
According to Shreyas Doshi on Lenny's Podcast, the integration requirement most commonly omitted in cloud product TRDs is the failure handling specification — teams that document happy path integration but not failure modes produce systems where a downstream API outage cascades into a full product outage.
Section 5: Data Residency Requirements
Primary data residency: [US / EU / APAC / Customer-specified]
Cross-border data transfer restrictions:
- EU customer data: Must remain in EU regions (GDPR Article 46)
- UK customer data: Post-Brexit transfer mechanisms
- Data localization requirements: [Any country-specific requirements]
Multi-tenancy isolation:
- Tenant data isolation model: [Shared database with row-level security / Dedicated database per tenant / Dedicated schema per tenant]
- Tenant blast radius: [Can one tenant's activity affect another tenant's performance?]
FAQ
Q: What should a cloud-based product technical requirements document include? A: Five sections: availability and SLA requirements (uptime targets, RTO/RPO), scalability requirements (peak load specs, auto-scaling triggers), security and compliance requirements (data classification, compliance frameworks), integration requirements (protocols, failure handling), and data residency requirements.
Q: What is the difference between RTO and RPO in a cloud product TRD? A: Recovery Time Objective (RTO) is the maximum acceptable downtime after an incident. Recovery Point Objective (RPO) is the maximum acceptable data loss measured in time. A product with RTO of 4 hours and RPO of 1 hour must be restored within 4 hours and may lose at most 1 hour of data.
Q: What availability percentage should a cloud product target? A: 99.9% (8.7 hours downtime/year) for standard B2B SaaS. 99.95% (4.4 hours) for products with critical workflows. 99.99% (52 minutes) for mission-critical applications. Each 9 requires significantly more architectural investment.
Q: What scalability requirements are most commonly omitted in cloud product TRDs? A: Scale-out time (how quickly can new compute instances be provisioned under spike traffic?), database read/write ratio (how much read replica capacity is needed?), and failure handling for integrations (what happens when a dependent API goes down?).
Q: When do you need data residency requirements in a cloud product TRD? A: Whenever you serve customers in the EU (GDPR requires data to remain in EU regions unless specific transfer mechanisms are in place), when enterprise customers have contractual data localization requirements, or when operating in regulated industries with country-specific data handling rules.
HowTo: Write a Cloud-Based Product Technical Requirements Document
- Define availability and SLA requirements including uptime percentage, deployment model (multi-region active-active or active-passive), RTO, RPO, and latency SLAs for each key API endpoint
- Specify scalability requirements with peak load multiples, auto-scaling trigger thresholds, scale-out time requirements, and database read/write ratio for proper read replica planning
- Classify all data types (PII, financial, usage) with encryption requirements, retention periods, and the compliance frameworks that apply to the product
- Document each external integration with protocol, authentication method, rate limits, and failure handling strategy including retry logic and dead letter queue requirements
- Specify data residency requirements for each geographic region served and define the multi-tenancy isolation model (shared database, dedicated database, or dedicated schema)