SLA Report

SLA Report 
 
 Project: Bilko
 Version: 0.1
 Date: 2026-02-23
 Author: Ops Architect
 Status: Draft (Template — fill in monthly)
 Reviewers: Tech Lead, Alem Bašić 
 
 Document History 
 
 
 
 Version 
 Date 
 Author 
 Changes 
 
 
 
 
 0.1 
 2026-02-23 
 Ops Architect 
 Initial draft 
 
 
 
 
 INSTRUCTIONS 
 Generate monthly SLA reports by the 5th business day of the following month.
File location: docs/operations/sla-reports/SLA-YYYY-MM.md 
 
 SLA Report: [Month YYYY] 
 Reporting Period: YYYY-MM-01 to YYYY-MM-[last day]
 Report Date: YYYY-MM-DD
 Prepared by: Ops Architect 
 
 1. SLA Summary 
 Service Level Objectives (SLOs) 
 
 
 
 SLO 
 Target 
 Actual 
 Status 
 
 
 
 
 API availability 
 ≥ 99.5% / month 
 X.XX% 
 ✅ / ❌ 
 
 
 API P95 response time 
 < 500ms 
 XXXms 
 ✅ / ❌ 
 
 
 API error rate (5xx) 
 < 0.5% 
 X.XX% 
 ✅ / ❌ 
 
 
 Frontend availability 
 ≥ 99.9% / month 
 X.XX% 
 ✅ / ❌ 
 
 
 Uptime (combined) 
 ≥ 99.5% / month 
 X.XX% 
 ✅ / ❌ 
 
 
 
 SLO Calculation 
 API Availability = (Total minutes in month - Downtime minutes) / Total minutes × 100

Total minutes in month (28 days) = 40,320
Total minutes in month (31 days) = 44,640

Allowed downtime at 99.5%:
- 28-day month: 201.6 minutes = ~3h 22min
- 31-day month: 223.2 minutes = ~3h 43min
 
 
 2. Uptime Metrics 
 API (api.bilko.io) 
 
 
 
 Metric 
 Value 
 
 
 
 
 Measured uptime 
 X.XX% 
 
 
 Total downtime 
 X minutes 
 
 
 Number of incidents 
 X 
 
 
 Longest outage 
 X minutes 
 
 
 
 Frontend (bilko.io) 
 
 
 
 Metric 
 Value 
 
 
 
 
 Measured uptime 
 X.XX% 
 
 
 Total downtime 
 X minutes 
 
 
 Number of incidents 
 X 
 
 
 
 Source: BetterStack uptime monitoring (1-min check interval) 
 
 3. Performance Metrics 
 API Response Times 
 
 
 
 Metric 
 Target 
 Week 1 
 Week 2 
 Week 3 
 Week 4 
 Month Avg 
 
 
 
 
 P50 
 < 100ms 
 
 
 
 
 
 
 
 P95 
 < 500ms 
 
 
 
 
 
 
 
 P99 
 < 1000ms 
 
 
 
 
 
 
 
 
 Critical Endpoint Performance 
 
 
 
 Endpoint 
 P95 Target 
 P95 Actual 
 Status 
 
 
 
 
 POST /api/v1/invoices 
 < 500ms 
 XXXms 
 ✅ / ❌ 
 
 
 GET /api/v1/invoices 
 < 200ms 
 XXXms 
 ✅ / ❌ 
 
 
 GET /api/v1/reports/vat 
 < 3000ms 
 XXXms 
 ✅ / ❌ 
 
 
 POST /api/v1/auth/login 
 < 300ms 
 XXXms 
 ✅ / ❌ 
 
 
 
 Source: Railway metrics + Sentry performance monitoring 
 
 4. Error Metrics 
 Error Rate by Week 
 
 
 
 Week 
 Total Requests 
 5xx Errors 
 Error Rate 
 Status 
 
 
 
 
 Week 1 
 
 
 X.XX% 
 
 
 
 Week 2 
 
 
 X.XX% 
 
 
 
 Week 3 
 
 
 X.XX% 
 
 
 
 Week 4 
 
 
 X.XX% 
 
 
 
 Month 
 
 
 X.XX% 
 
 
 
 
 Top Errors (Sentry) 
 
 
 
 # 
 Error 
 Count 
 Affected Users 
 Status 
 
 
 
 
 1 
 [Error message] 
 X 
 X 
 Fixed / Investigating 
 
 
 2 
 
 
 
 
 
 
 3 
 
 
 
 
 
 
 
 
 5. Incidents This Month 
 
 
 
 Incident ID 
 Date 
 Duration 
 Severity 
 Root Cause 
 Resolved 
 
 
 
 
 INC-YYYY-MM-DD-001 
 YYYY-MM-DD 
 X min 
 P0/P1/P2 
 [Short description] 
 Yes 
 
 
 
 Total downtime from incidents: X minutes
 P0 incidents: X (target: 0)
 P1 incidents: X (target: < 2/month) 
 
 6. Financial Data Integrity (Monthly Verification) 
 Required: Verify no financial data corruption occurred this month. 
 
 
 
 Check 
 Method 
 Result 
 
 
 
 
 Double-entry balance 
 SQL: SUM(debits) = SUM(credits) per org 
 ✅ Balanced / ❌ Issues found 
 
 
 Invoice total accuracy 
 SQL: total = subtotal + tax - discount 
 ✅ Accurate / ❌ Issues found 
 
 
 VAT calculation accuracy 
 Spot-check 10 random invoices 
 ✅ Accurate / ❌ Issues found 
 
 
 No orphaned transactions 
 SQL: all transactions have debit+credit 
 ✅ Clean / ❌ Issues found 
 
 
 
 Verification queries run on: YYYY-MM-DD
 Verified by: [Name] 
 -- Monthly double-entry balance verification
SELECT
 o.name as organization_name,
 SUM(CASE WHEN te.type = 'debit' THEN te.amount ELSE 0 END) as total_debits,
 SUM(CASE WHEN te.type = 'credit' THEN te.amount ELSE 0 END) as total_credits,
 ABS(SUM(CASE WHEN te.type = 'debit' THEN te.amount ELSE -te.amount END)) as imbalance
FROM transaction_entries te
JOIN transactions t ON t.id = te."transactionId"
JOIN organizations o ON o.id = t."organizationId"
WHERE t.created_at >= DATE_TRUNC('month', CURRENT_DATE)
 AND t.created_at < DATE_TRUNC('month', CURRENT_DATE) + INTERVAL '1 month'
GROUP BY o.id, o.name
HAVING ABS(SUM(CASE WHEN te.type = 'debit' THEN te.amount ELSE -te.amount END)) > 0.0001
ORDER BY imbalance DESC;
-- Expected: 0 rows (all organizations balanced)
 
 
 7. Infrastructure Metrics 
 Railway (Backend + Database) 
 
 
 
 Resource 
 Average 
 Peak 
 Trend 
 
 
 
 
 API CPU 
 X% 
 X% 
 Stable / Growing / Decreasing 
 
 
 API Memory 
 XMB 
 XMB 
 Stable / Growing / Decreasing 
 
 
 DB Connections 
 X avg 
 X peak 
 Stable / Growing 
 
 
 DB Storage 
 XGB 
 — 
 +X GB this month 
 
 
 
 Vercel (Frontend) 
 
 
 
 Metric 
 Value 
 
 
 
 
 Total page views 
 X 
 
 
 Unique visitors 
 X 
 
 
 Average LCP 
 Xms 
 
 
 Average CLS 
 X 
 
 
 
 
 8. Cost Report 
 
 
 
 Service 
 Budget 
 Actual 
 Variance 
 
 
 
 
 Railway (API + DB) 
 €20 
 €XX 
 +/-€XX 
 
 
 Vercel 
 €0 
 €XX 
 +/-€XX 
 
 
 Cloudflare R2 
 €1 
 €XX 
 +/-€XX 
 
 
 SendGrid 
 €0 
 €XX 
 +/-€XX 
 
 
 Total 
 €21 
 €XX 
 +/-€XX 
 
 
 
 
 9. SLA Trending 
 
 
 
 Month 
 API Uptime 
 P95 Latency 
 Error Rate 
 Incidents 
 
 
 
 
 [Previous -2] 
 — 
 — 
 — 
 — 
 
 
 [Previous -1] 
 — 
 — 
 — 
 — 
 
 
 [This month] 
 X.XX% 
 XXXms 
 X.XX% 
 X 
 
 
 
 
 10. Action Items from This Report 
 
 
 
 # 
 Issue 
 Action 
 Owner 
 Due 
 
 
 
 
 1 
 [Issue] 
 [Action] 
 [Owner] 
 YYYY-MM-DD 
 
 
 
 
 Approval 
 
 
 
 Role 
 Name 
 Date 
 Signature 
 
 
 
 
 Author 
 Ops Architect 
 
 
 
 
 Reviewer 
 Alem Bašić