The verdict in three sentences
Securing the availability of a critical app in Toronto in 2026 combines three items: monitoring (80-300 EUR/month), 24/7 on-call (1,500-4,000 EUR/month) and a contractual SLA (99.9% vs 99.95%). The trade-off rests on one simple metric: the cost of one hour of downtime for your business. Once an hour of outage exceeds a few thousand EUR in revenue or penalties, 24/7 on-call becomes the cheapest insurance in your stack.
The three building blocks and their 2026 cost
Monitoring, on-call and SLA are complementary: one detects, one repairs, the third commits contractually. Here are the ranges.
| Block | Scope | 2026 cost (EUR/month) |
|---|---|---|
| Error monitoring (Sentry-type) | Traces + alerts | 80 - 150 |
| Uptime monitoring + APM | Probes + perf | 100 - 300 |
| Business-hours on-call | Same-day response | 800 - 1,500 |
| 24/7 on-call | Rotation, escalation | 1,500 - 4,000 |
| PITR backups | Second-level restore | 50 - 200 |
| SLA 99.9% | 8.7 h downtime/year max | included |
| SLA 99.95% | 4.4 h downtime/year max | +30-50% |
The target MTTR (Mean Time To Repair) is the real promise: aiming for under 30 minutes requires a tooled on-call (runbooks, alerts, ready access), not just a phone number.
SLA: what each level guarantees
The availability percentage translates into tolerated hours of outage. Choosing 99.95% over 99.9% halves annual downtime but raises on-call cost.
| SLA level | Max downtime/year | Max downtime/month | Typical use |
|---|---|---|---|
| 99.0% | 87.6 h | 7.3 h | Internal app |
| 99.5% | 43.8 h | 3.6 h | Business tool |
| 99.9% | 8.7 h | 43 min | B2B customer app |
| 99.95% | 4.4 h | 22 min | Sales platform |
| 99.99% | 52 min | 4.3 min | Payments / real-time |
Demanding 99.99% on an internal app is waste; demanding it on a platform that collects money is a necessity. The right SLA is calculated, not copied.
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Mini case study
Thomas, COO of a B2B logistics platform in Toronto, runs an app processing 1,800 orders/day at 90 EUR average margin. One hour of daytime downtime costs him roughly 6,750 EUR in lost orders (75 orders x 90 EUR), not counting contractual customer penalties.
He subscribes to APM monitoring (250 EUR/month), 24/7 on-call (2,800 EUR/month) and PITR (150 EUR/month), totaling 3,200 EUR/month or 38,400 EUR/year. Before, he suffered around 14 hours of downtime/year; on-call brings that to 4 hours with an MTTR under 30 min. The 10 avoided hours represent 67,500 EUR of saved orders, a 1.75x ROI in the first year, avoided customer penalties on top.
FAQ
What is the difference between monitoring and on-call? Monitoring (80-300 EUR/month) detects and alerts automatically. On-call (1,500-4,000 EUR/month) is the human team that answers, diagnoses and fixes outside business hours. One without the other leaves a hole overnight.
99.9% or 99.95%, how to choose? Calculate the cost of one hour of downtime. If going from 8.7 h to 4.4 h annual downtime avoids more loss than the 30-50% on-call premium, pick 99.95%. Otherwise 99.9% is enough.
What does a 30-minute target MTTR cover? It is the average time between detection and return to normal. Reaching it requires runbooks, precise alerts and pre-configured access, not just a reachable person.
Are PITR backups essential? For a critical app, yes. Point-In-Time Recovery restores the database to the second before an incident (50-200 EUR/month), the difference between losing 5 minutes or a full day of data.
Can we start small and scale up? Yes. Many start with monitoring + business-hours on-call (around 1,200 EUR/month) then move to 24/7 when the revenue the app carries justifies it. The contract should plan for this ramp-up.
Let's scope your project. Give us the transaction volume, margin per transaction and estimated cost of one hour of outage: we'll size monitoring, on-call and SLA at the right level. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
