What we promise on uptime.
This SLA is the contractual uptime, response and credit framework for paid YionStack plans. It is incorporated into your Terms of Service and applies from the day your subscription begins. Live operational status lives at /status.
- Version
- v1.0
- Effective
- 26 April 2026
- Measurement window
- Calendar month
- Currency for credits
- GBP
1. Uptime by plan
We measure uptime as the percentage of minutes in a calendar month during which the production YionStack service responds successfully to a baseline health probe. The probe runs every 60 seconds from at least three independent geographies.
No service credits — best-effort tier
Up to 25% of monthly fee
Up to 50% of monthly fee
99.9% monthly uptime equates to ~43 minutes of permitted downtime per month; 99.95% equates to ~21 minutes. Anything beyond that, on a paid Growth or higher plan, triggers the credit table in section 3.
2. Response and resolution targets
Response is the time we take to confirm receipt and assign an engineer. Resolution is when service is restored to a working state — not necessarily a full root-cause fix, which we publish on /status as a retrospective.
- P1 — CriticalTotal outage; data loss; widespread inability to sign in or transact.Response:15 minutes (24/7)Resolution:Continuous engineering effort until restored
- P2 — MajorA core module is down or seriously degraded; sensible workaround unavailable.Response:1 hour (business day) · 2 hours (out of hours)Resolution:Same business day where reasonably achievable
- P3 — MinorSingle feature impaired; workaround exists.Response:1 business dayResolution:Within current release cycle
- P4 — CosmeticVisual issue, typo, low-impact polish.Response:3 business daysResolution:Bundled with the next release
3. Service credits
If we miss the monthly uptime target on a Growth or higher plan, you are entitled to a credit on your next invoice. Credits are your sole and exclusive remedy for SLA failure, calculated as a percentage of the affected month's fee.
| Achieved uptime | Credit (Growth) | Credit (Scale / Enterprise) |
|---|---|---|
| < 99.9% but ≥ 99.0% | 10% | 15% |
| < 99.0% but ≥ 95.0% | 25% | 30% |
| < 95.0% | 25% | 50% |
How to claim
Email billing@yionstack.co.uk within 30 days of the affected month with your account, the dates of impact, and the impact you experienced. We confirm or query within 5 business days. Approved credits appear on your next invoice and never expire while your account is active.
4. What this SLA does not cover
Five categories sit outside the uptime calculation. We list them explicitly so there is no ambiguity later.
- Scheduled maintenance announced at least 48 hours in advance on /status
- Force majeure — events outside our reasonable control (sustained internet outages, ISP failures, regulatory disruption)
- Customer-side issues: misconfiguration, account suspension for non-payment, customer-initiated DNS changes that point away from YionStack
- Third-party services we depend on but do not control, only insofar as the dependency itself is genuinely unavailable (e.g. HMRC MTD downtime, Companies House outages)
- Beta features explicitly labelled as such in the product or on the roadmap