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API · /flowrate-api

Flow Rate API

healthy 4,789 Subscribers

Pipe-flow maths as an API, computed locally and deterministically. The flow endpoint relates the three quantities of pipe flow — volumetric flow rate, fluid velocity and pipe diameter — through the continuity relation Q = A·v (with A = π/4·D²): give any two and it returns the third, with the flow rate expressed in litres per second and minute, cubic metres per hour, US gallons per minute and cubic feet per minute, plus the velocity and the pipe cross-section. The reynolds endpoint computes the Reynolds number from velocity, diameter and the fluid (water, air, oil and more, or a custom kinematic viscosity) and classifies the flow as laminar, transitional or turbulent. The convert endpoint converts a flow rate between litres per second and minute, cubic metres per hour, US gallons per minute, cubic feet per minute and per second. Everything is computed locally and deterministically, so it is instant and private. It is computed in SI internally; Reynolds uses the kinematic viscosity at about 20°C. Ideal for plumbing and HVAC tools, pump and irrigation sizing, process and fluid-engineering software, and hydraulics calculators. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is fluid flow in pipes; for plain volume or unit conversion use a unit-conversion API.

#flow-rate #pipe #reynolds #hydraulics #engineering #developer-tools
api.oanor.com/flowrate-api
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Machine-readable spec so AI agents can integrate this API.

/api/flowrate-api/openapi.json
/api/flowrate-api/llms.txt

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Flow Rate API — live data on the oanor API marketplace

API health

healthy
Uptime
100.00%
Server probes · 24h
Avg latency
71 ms
Server probes · 24h
Subscribers
4,789
active
Total calls
76
last 7 days
status Full status page → · 12 probes/24h

Pricing

Pick a tier — billed monthly, cancel anytime.

Free

Free

  • 11,135 calls / month
  • 2 requests / second
  • Hard cap (429 above quota, no overage)
  • 11,135 calls/month
  • 2 req/sec
  • Flow + Reynolds + convert
  • No credit card
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Starter

€12.65 /month

  • 20,750 calls / month
  • 8 requests / second
  • Hard cap (429 above quota, no overage)
  • 20.75k calls/month
  • 8 req/sec
  • Fluids + metric/imperial
  • Email support
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Pro

€32.55 /month

  • 257,500 calls / month
  • 20 requests / second
  • Hard cap (429 above quota, no overage)
  • 257.5k calls/month
  • 20 req/sec
  • HVAC / hydraulics pipelines
  • Priority support
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Mega

€70.55 /month

  • 1,330,000 calls / month
  • 50 requests / second
  • Hard cap (429 above quota, no overage)
  • 1.33M calls/month
  • 50 req/sec
  • Platform scale
  • Dedicated SLA
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Related APIs

Other APIs with overlapping tags.

Reynolds Number API — oanor API marketplace

Reynolds Number API

Dimensionless flow-number maths for fluid-mechanics similitude as an API, computed locally and deterministically. The reynolds endpoint computes the Reynolds number, Re = v·L/ν = ρvL/μ — the ratio of inertial to viscous forces — from the velocity, a characteristic length (pipe diameter) and either the kinematic viscosity or the density and dynamic viscosity, and classifies the flow as laminar (< 2300), transitional (2300–4000) or turbulent (> 4000). The froude endpoint computes the Froude number, Fr = v/√(g·L) — the ratio of inertia to gravity used for open-channel and ship flows — together with the critical velocity, and tells you whether the flow is subcritical (tranquil), critical or supercritical (shooting). The mach endpoint computes the Mach number, M = v/c, with the sound speed taken directly or worked out from the air temperature, c = √(γRT), and classifies the speed as subsonic, transonic, supersonic or hypersonic. Everything is computed locally and deterministically, so it is instant and private. Ideal for fluid-mechanics, aerodynamics and hydraulics tools, model-scaling and wind-tunnel similitude, pipe-flow and open-channel analysis, and engineering education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is dimensionless-number similitude; for pipe friction pressure drop use a Darcy-Weisbach API and for open-channel uniform flow use a Manning API.

api.oanor.com/reynolds-api

 Water Hammer API — oanor API marketplace

Water Hammer API

Water-hammer (hydraulic-transient) maths as an API, computed locally and deterministically — the surge-pressure, wave-speed and valve-timing numbers a piping or plumbing engineer guards a system with. The surge endpoint applies the Joukowsky equation Δp = ρ · a · Δv: a sudden stop of the flow spikes the pressure by the fluid density × the pressure-wave speed × the velocity change — stopping 2 m/s of water at a ≈ 1200 m/s adds about 24 bar (348 psi), far above the line pressure, which is what bangs the pipes and can split fittings. The wave-speed endpoint gives that pressure-wave speed: a = √(K/ρ) in a rigid pipe (≈ 1,480 m/s for water), slowed in a real elastic pipe to √(K/ρ) ÷ √(1 + (K·D)/(E·t)) — a thin or plastic pipe gives a lower wave speed and a gentler surge, which is why PVC tolerates hammer better than steel. The critical-time endpoint gives 2L/a, the round-trip time of the wave: close a valve faster than this and you get the full Joukowsky surge, slower and the returning relief wave eats into it, so sizing closure times (or fitting a surge tank or air chamber) above the critical time is the standard cure. Everything is computed locally and deterministically, so it is instant and private. Ideal for piping- and plumbing-design tools, pump-station and pipeline-surge analysis, and hydraulic-engineering utilities. Pure local computation — no key, no third-party service, instant. Idealised single-pipe transient. 3 compute endpoints. For steady pipe pressure drop use a Darcy API; for pump head and affinity a pump API.

api.oanor.com/waterhammer-api

 Hydraulic Cylinder API — oanor API marketplace

Hydraulic Cylinder API

Hydraulic-cylinder engineering maths as an API, computed locally and deterministically — the force, speed and oil-volume numbers a fluid-power designer, machine builder or hydraulics technician sizes a cylinder with. The force endpoint gives the push and pull from the bore, rod diameter and working pressure: extending, the oil acts on the full bore area, so the cylinder is strongest pushing out; retracting, it acts only on the annulus left by the rod, giving less force — a 100 mm bore with a 56 mm rod at 160 bar pushes about 125.7 kN out but pulls only 86.3 kN back, which is why a press or an excavator does its hard work on the extend stroke. The speed endpoint gives the piston speed from the pump flow (speed = flow ÷ area), so extending is the slower stroke and retracting the faster, the trade-off every circuit designer balances against force. The volume endpoint gives the swept oil volume per stroke for extend and retract, the rod displacement and the bore-to-annulus area ratio — the differential (regeneration) ratio used to speed the extend stroke in a regen circuit — so the pump, tank and lines can be sized for the larger volume. Everything is computed locally and deterministically, so it is instant and private. Ideal for fluid-power and machine-design tools, hydraulics-sizing calculators, mobile- and industrial-equipment utilities, and engineering apps. Pure local computation — no key, no third-party service, instant. Ideal-area estimates — allow for friction, back-pressure and efficiency. 3 compute endpoints. For Pascal force-multiplication use a hydraulics API; for valve sizing a valve-flow (Cv/Kv) API.

api.oanor.com/hydrauliccylinder-api

 O-Ring Seal API — oanor API marketplace

O-Ring Seal API

O-ring seal-design maths as an API, computed locally and deterministically — the squeeze, gland and stretch numbers an engineer or maker designs a seal to. The squeeze endpoint gives the compression that makes the seal: squeeze = (cross-section − gland depth) ÷ cross-section, so a 0.139-inch cord in a 0.113-inch deep groove is squeezed 18.7 %, and it grades the result — roughly 10–16 % suits dynamic (reciprocating) seals and 15–30 % static ones — and, given the groove width, the gland fill percentage, which should stay under about 85 % so the rubber has room to expand from heat or fluid swell. The gland endpoint works the other way: from the cross-section and whether the seal is static or dynamic (or a target squeeze) it returns the groove depth and a width sized for about 70 % fill — typically 1.3 to 1.5 times the cross-section — plus a corner radius. The stretch endpoint checks installation: stretch = (mating diameter − o-ring ID) ÷ ID, which should stay under about 5 % on a rod because stretching thins the cross-section and steals squeeze. Everything is computed locally and deterministically, so it is instant and private. Ideal for mechanical-engineering, hydraulics, pneumatics, vacuum and product-design app developers, seal-selection and gland-design tools, and CAD plugins. Pure local computation — no key, no third-party service, instant. Inches or millimetres. Live, nothing stored. 3 compute endpoints.

api.oanor.com/oring-api

Frequently asked questions

Quick answers about pricing, quotas, and integration.

How do I get an API key for Flow Rate API?
Sign up for free at oanor.com, generate an API key from the developer dashboard, and call Flow Rate API with the x-oanor-key header. No credit card needed for the free tier.
What's the rate limit for Flow Rate 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 Flow Rate API cost?
Flow Rate API has a free tier with 100 calls / month. Paid plans start at €12.65 / 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 Flow Rate API GDPR-compliant?
All requests to Flow Rate 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/flowrate-api/SOME_PATH \
  -H "x-oanor-key: oanor_test_..."
const res = await fetch("https://api.oanor.com/flowrate-api/SOME_PATH", {
  headers: { "x-oanor-key": "oanor_test_..." }
});
const data = await res.json();
$ch = curl_init("https://api.oanor.com/flowrate-api/SOME_PATH");
curl_setopt($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/flowrate-api/SOME_PATH",
    headers={"x-oanor-key": "oanor_test_..."},
)
print(r.json())

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