Which cloud uptime monitors support sub-minute check intervals?

Marketing pages love "30-second checks" until your phone buzzes at 2 a.m. because a CDN hiccuped twice. Sub-minute intervals — how often a cloud service pings your URL from outside — multiply false alarms and cost. After this guide you will compare Checkly, Better Stack, StatusCake, Hyperping, and StillOnline, calculate worst-case detection time, and decide if 1 minute is enough without a $64+/mo stack.

Quick answer

Sub-minute means checks faster than 60 seconds — usually 30s on paid tiers. Worst-case downtime detection is roughly interval × failed checks before alert (StillOnline waits for two failures). Per Better Stack docs, free uptime checks run every 3 minutes; paid plans reach 30 seconds. Checkly Team at $64/mo is the common path to 30s with synthetic depth. StillOnline Ultimate ($29/mo) floors at 1 minute, not 30 seconds — honest tradeoff for bundled status pages. Hyperping Essentials ($24/mo) and Better Stack paid also reach 30s. For many B2B micro-SaaS teams without on-call SLA, 5 minutes on Free or 1 minute on Ultimate is enough if you tune alert fatigue.

Check interval is not the same as alert latency. Interval is the schedule; latency adds probe time, vendor queue, and your notification channel (email, Telegram, Slack).

1 min vs 30s vs 5 min tradeoffs for your SLA

Uptime monitoring is an outside robot that opens your site on a timer — like a friend texting "you up?" every few minutes. A shorter timer finds outages sooner but also catches brief blips that self-heal before customers notice.

Worst-case detection formula:
interval × fail threshold = minutes before DOWN alert (add ~1 min worker tick on StillOnline)

Example: 30-second checks with two failures before alert means up to ~60 seconds of blind downtime plus probe and notification delay. At 5 minutes with the same rule, worst case is ~10 minutes — often acceptable when you have no contractual uptime SLA and no paid on-call rotation.

Do: write your real SLA on paper (contract, investor deck, or "best effort") before picking an interval. Do not: buy 30-second checks because competitors list them — faster is not better if nobody responds at night.

1. Step 1: Define who gets paged and within what window (15 min, 1 hour, next business day).
2. Step 2: Multiply interval by your vendor fail threshold for worst-case detection.
3. Step 3: Compare that number to your SLA promise, not to a competitor headline.
4. Step 4: Test a flaky staging URL at 30s for one day — count noisy alerts.
5. Step 5: Pick the slowest interval that still meets your promise and budget.

When 5 minutes is enough for indie SaaS without on-call

Solo founders on Vercel, Railway, or Fly.io often ship one prod URL plus a public status page. If customers expect transparency, not 99.99% contract uptime, 5-minute checks cover most incidents before social media does.

Do: stay on StillOnline Free (5 min locked), StatusCake Free at 5 min, or Hyperping Free while you validate product-market fit. Pair with a clear status page so B2B buyers see history, not just a green dot. Do not: pay for sub-minute probes when your runbook says "fix tomorrow morning."

Upgrade triggers: signed SLA below 10 minutes, revenue large enough to fund on-call, or repeated false positives at 1 minute that you cannot tune — see the alert tuning guide.

False positive cost of aggressive intervals

A 15-second interval runs about 5,760 checks per URL per day per uptime monitoring guides (June 2026). Each check is a network round trip — Wi-Fi blips, cold starts, and rate limits can fail once without a real outage.

Do: require two consecutive failures before DOWN (StillOnline default pattern) and monitor a dedicated /health URL, not a heavy HTML page. Do not: point 30s checks at endpoints that sometimes return 503 during deploys — you will train yourself to ignore alerts.

Alert fatigue loop: 30s interval → flaky endpoint → nightly pings → you mute channel → real outage missed

Comparison: Checkly, Better Stack, StatusCake, Hyperping, StillOnline

Vendor docs and pricing pages, June 2026. Confirm before procurement.

Verdict: Need true 30s on a budget — Hyperping Essentials ($24/mo) or Better Stack paid. Need sub-minute plus synthetic/browser depth — Checkly Team ($64/mo). Need 1 minute with auto status page and flat $29 for up to 100 projects — StillOnline Ultimate is honest: not 30s, but enough for most indie B2B without enterprise spend.

Do: match tier price to how many URLs and status pages you operate. Do not: assume StillOnline Ultimate runs 30-second checks — it does not.

Honest StillOnline Ultimate 1–5 minute limits

StillOnline tiers (Free $0, Pro $9/mo, Ultimate $29/mo) bundle HTTP checks with an auto public status page. Interval choices in the UI depend on plan:

• Free: effectively 300 seconds (5 min); faster options appear disabled.
• Pro: 300 / 180 / 120 seconds (5 / 3 / 2 min).
• Ultimate: 60–300 seconds (1–5 min) — fastest is 1 minute, not sub-minute.

Workers run on a 1-minute tick, then honor your chosen interval_seconds. Two failed checks before marking DOWN adds another interval of delay — same pattern described in our Telegram alerts workflow.

Do: pick Ultimate when you outgrow Pro project caps and need 1-minute prod checks across a client portfolio. Start Free at stillonline.tech/app; compare tiers at pricing and the plan picker guide. Do not: quote StillOnline as a 30-second monitor in RFPs — say 1 minute minimum on Ultimate.

Do / Do not when choosing interval

Run this before you change interval or switch vendors.

1. Do: Document worst-case detection (interval × failures + notification delay).
2. Do: Use a lightweight health URL, not your marketing homepage.
3. Do: Trial 30s on staging if you consider Hyperping or Better Stack.
4. Do: Keep 5 min until you have someone who responds within 15 minutes.
5. Do: Re-read indie SaaS monitoring picks when you add a second prod URL.
6. Do not: Pay $64/mo for 30s if your status page and email alerts are the real customer touchpoint.
7. Do not: Enable sub-minute checks on endpoints with known cold-start spikes.
8. Do not: Confuse check interval with how fast your status page updates for visitors — both matter, but they are different clocks.

Do: treat interval as a product decision tied to support capacity. Do not: copy a competitor matrix into your security questionnaire without testing your own runbook.

What to do next

Calculate worst-case minutes, fill the comparison table for your budget, then pick the slowest interval that still matches your promise. Most indie B2B teams land on 5 min (Free) or 1 min (Ultimate) without needing Checkly-scale sub-minute spend.

Related guides

• False positive uptime alerts tuning — cut noise before you shorten intervals.
• Which StillOnline plan to pick — Free vs Pro vs Ultimate intervals.
• Best uptime monitoring for indie SaaS 2026 — shortlist beyond interval math.
• Health check URL quickstart — ship /health before you compare vendors.

FAQ

What is the minimum check interval on StillOnline Ultimate?

60 seconds (1 minute), selectable up to 300 seconds (5 minutes). Ultimate does not offer 30-second or sub-minute checks. Pro maxes at 2 minutes; Free stays at 5 minutes. See plan picker.

Do I need a 30-second interval for indie SaaS without SLA?

Usually no. If nobody is on call within 15 minutes, 5-minute checks plus a public status page cover transparency. Upgrade when a contract or churn risk demands faster detection.

What is the difference between check interval and alert latency?

Interval is how often probes run. Alert latency adds failed-check rules, queue time, and your channel (Telegram, email, Slack). A 30s interval does not mean a 30s text message — see Telegram owner alerts.

Which Checkly plan includes 30-second checks?

Team at $64/mo per Checkly pricing (June 2026). Starter ($24/mo) stops at 1 minute; Hobby Free at 2 minutes. Enterprise can go to 1 second on request.

What interval does Better Stack Free use?

3 minutes on the free uptime tier per Better Stack check frequency docs. Paid plans can go down to 30 seconds.

How much does 30-second monitoring cost on StatusCake?

Business tier around €58.33/mo (annual billing) for 30-second intervals per StatusCake pricing. Superior (~€16.66/mo) gives 1 minute, not 30 seconds.

Hyperping vs Better Stack — who is faster on entry paid?

Both reach 30 seconds on paid tiers. Hyperping Essentials at $24/mo advertises 30s; Better Stack paid ~$29/mo Responder also reaches 30s. Compare status-page workflow and monitor limits for your stack — or StillOnline Ultimate if 1 minute with bundled status is enough.