Confidence interval
API · /inference-api
Statistical Inference API
healthy
4,030 Subscribers
Inferential-statistics maths as an API, computed locally and deterministically. The samplesize endpoint computes how many respondents a survey or experiment needs for a proportion, n = Z²·p(1−p)/E², from a confidence level and a margin of error (using p = 0.5 for the most conservative size), with a finite-population correction when the population is known. The confidence endpoint builds a confidence interval for a mean (estimate ± Z·σ/√n) or a proportion (p ± Z·√(p(1−p)/n)), returning the standard error, margin of error and the lower and upper bounds. The ztest endpoint runs a one-sample z-test, z = (x̄ − μ₀)/(σ/√n), and returns the z-score, the one- or two-tailed p-value and whether the result is significant at the chosen alpha. The z-scores come from an exact inverse-normal and the p-values from the normal CDF. Everything is computed locally and deterministically, so it is instant and private. Ideal for A/B-testing, survey, research and analytics app developers, experiment dashboards and data-science tools, and education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is inferential statistics; for descriptive statistics use a statistics API and for probability distributions use a probability API.
api.oanor.com/inference-api
API health
healthy- Uptime
- 100.00%
- Server probes · 24h
- Avg latency
- 78 ms
- Server probes · 24h
- Subscribers
- 4,030
- active
- Total calls
- 76
- last 7 days
Pricing
Pick a tier — billed monthly, cancel anytime.
Free
Free
- 3,000 calls / month
- 2 requests / second
- Hard cap (429 above quota, no overage)
- Sample-size & confidence-interval endpoints
- Single z-test per call
- Deterministic local compute, no data cost
Starter
€5.00 /month
- 40,000 calls / month
- 5 requests / second
- Hard cap (429 above quota, no overage)
- All inference endpoints
- One- & two-proportion z-tests
- Margin-of-error & power inputs
- Email support
Pro
€15.00 /month
- 250,000 calls / month
- 15 requests / second
- Hard cap (429 above quota, no overage)
- High-throughput survey-design batches
- Finite-population correction
- Confidence levels 80-99.9%
- Priority support
Mega
€49.00 /month
- 1,571,000 calls / month
- 40 requests / second
- Hard cap (429 above quota, no overage)
- Bulk experiment power analysis
- Unlimited z-test variants
- Lowest per-call cost at scale
- SLA-backed availability
Built by
Related APIs
Other APIs with overlapping tags.
Sample Size API
Survey and poll sample-size planning as an API, computed locally and deterministically. The proportion endpoint computes the number of respondents needed to estimate a proportion within a target margin of error at a chosen confidence level, n = z²·p(1−p)/E², defaulting to the worst-case p = 0.5 that maximises the required size, with an optional finite-population correction n/(1 + (n−1)/N) for a known population — the classic ±5 % margin at 95 % confidence needs 385 responses, ±3 % needs 1 068, and capping the population at 1 000 cuts the ±5 % requirement to 278. The mean endpoint sizes a sample for estimating a mean to within a margin of error from the standard deviation, n = (z·σ/E)². The margin endpoint inverts the relationship, returning the margin of error a given sample size actually achieves. The critical z-value is computed from the confidence level with a high-accuracy inverse-normal so any confidence works, not just the textbook 90/95/99 %. Margins, proportions and confidence are decimals (0.05, 0.5, 0.95). Everything is computed locally and deterministically, so it is instant and private. Ideal for market-research, polling, UX-research, survey-platform, product-analytics and statistics-education app developers, study-planning and sample-size tools, and research software. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is sample-size planning with the normal approximation; for A/B-test significance use an A/B-test API and for descriptive statistics a statistics API.
api.oanor.com/samplesize-api
Sweden Municipal Statistics API
Swedish municipal and regional statistics straight from Kolada — the open database run by the Council for the Promotion of Municipal Analyses (RKA) — no key, read live. Kolada holds roughly 6,000 key performance indicators tracking the finances and service quality of all 290 Swedish municipalities and 21 regions: personnel costs, school results, elderly care, waiting times, environment, demographics and much more. The kpis endpoint lists and searches the indicator catalogue by title. The kpi endpoint returns the full metadata of a single indicator (its definition, operating area and source). The municipalities endpoint lists every municipality and region with its official code. The data endpoint returns a chosen indicator's full annual value series for a given municipality, with the latest value highlighted. The meta endpoint documents the API. Live data from Kolada v3, lightly cached. Live. 5 endpoints. This serves Swedish public-sector statistics; for the krona exchange rate or national CPI use an FX / national-statistics API.
api.oanor.com/kolada-api
Mongolia Statistics API
Official Mongolian inflation statistics straight from the National Statistics Office of Mongolia (NSO) via its 1212.mn PxWeb open-data service — no key, read live. The cpi endpoint returns the headline national Consumer Price Index (Overall index, base 2023=100) for the latest month with the index level plus month-on-month and year-on-year inflation, computed from the official series. The cpi/series endpoint returns the historical monthly CPI index and year-on-year rate over the last N months, ready to chart. The cpi/groups endpoint breaks the latest CPI down across all thirteen COICOP groups (food, housing, transport and so on) with index and annual change for each. The cpi/annual endpoint gives the annual-average CPI and average inflation for every year on record. The meta endpoint documents the source. Live data from Mongolia NSO PxWeb, lightly cached. Live. 5 endpoints. This serves Mongolian national price statistics; for the tugrik exchange rate use an FX / central-bank API.
api.oanor.com/mongolia-stats-api
North Macedonia Statistics API
Official North Macedonian inflation statistics straight from the State Statistical Office (MAKStat) via its ASKdata-style PxWeb open-data service — no key, read live. The cpi endpoint returns the headline Consumer Price Index inflation for the latest month — the month-on-month and year-on-year percentage changes (ECOICOP version 2 classification) — derived from the official ratio table. The cpi/series endpoint returns the historical monthly MoM and YoY series over the last N months, ready to chart. The cpi/groups endpoint breaks the latest year-on-year inflation down across all thirteen COICOP main groups (food, housing, transport and so on). The cpi/group endpoint returns the full MoM and YoY history for any single COICOP group by its code. The meta endpoint documents the COICOP group codes and source. Live data from MAKStat PxWeb, lightly cached. Live. 5 endpoints. This serves North Macedonian national price statistics; for the denar exchange rate use an FX / central-bank API.
api.oanor.com/macedonia-stats-api
Frequently asked questions
Quick answers about pricing, quotas, and integration.
How do I get an API key for Statistical Inference API?
Sign up for free at oanor.com, generate an API key from the developer dashboard, and call Statistical Inference API with the x-oanor-key header. No credit card needed for the free tier.
What's the rate limit for Statistical Inference API?
Free tier allows 1 request per second. Paid plans scale up to 50 requests per second on the Mega tier. Hard limits return HTTP 429 above the quota — no surprise overage charges.
How much does Statistical Inference API cost?
Statistical Inference API has a free tier with 100 calls / month. Paid plans start at €5.00 / month with higher quotas and faster rate limits.
Can I cancel my subscription anytime?
Yes. Plans are billed monthly and you can cancel anytime from your billing dashboard. No long-term contracts and no cancellation fee.
Is Statistical Inference API GDPR-compliant?
All requests to Statistical Inference API go through our EU-based gateway. Your upstream API key never leaves our server and no personal data is shared with the upstream provider beyond the request you send.
Pick an endpoint from the list on the left to see its details and try it.
Code snippets
Sign up to get an API key, then call any path under your slug.
curl https://api.oanor.com/inference-api/SOME_PATH \
-H "x-oanor-key: oanor_test_..."const res = await fetch("https://api.oanor.com/inference-api/SOME_PATH", {
headers: { "x-oanor-key": "oanor_test_..." }
});
const data = await res.json();$ch = curl_init("https://api.oanor.com/inference-api/SOME_PATH");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, ["x-oanor-key: oanor_test_..."]);
$response = curl_exec($ch);import requests
r = requests.get(
"https://api.oanor.com/inference-api/SOME_PATH",
headers={"x-oanor-key": "oanor_test_..."},
)
print(r.json())Ratings
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