API · /isentropic-api

Isentropic Flow API

healthy 3,826 Subscribers

Isentropic compressible-flow (gas-dynamics) maths as an API, computed locally and deterministically. The isentropic endpoint gives the stagnation-to-static ratios of a perfect gas from a Mach number and the heat-capacity ratio γ (1.4 for air): the temperature ratio T0/T = 1 + (γ−1)/2·M², the pressure ratio p0/p = (T0/T)^(γ/(γ−1)), the density ratio and the area ratio A/A* relative to the sonic throat, and classifies the flow as subsonic, sonic or supersonic. The stagnation endpoint turns a static temperature and pressure plus a Mach number into the stagnation (total) conditions, the speed of sound a = √(γRT) and the flow velocity. The mach endpoint inverts the relations, solving the Mach number from a pressure, temperature or area ratio — an area ratio gives both the subsonic and supersonic roots — or from a velocity and temperature. Everything is computed locally and deterministically, so it is instant and private. Ideal for aerospace, propulsion, nozzle-design and wind-tunnel app developers, supersonic-flow and ducting tools, and engineering education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is compressible isentropic flow; for the standard atmosphere use an atmosphere API and for incompressible Bernoulli flow a Bernoulli API.

api.oanor.com/isentropic-api
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Machine-readable spec so AI agents can integrate this API.

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

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API health

healthy
Uptime
100.00%
Server probes · 24h
Avg latency
88 ms
Server probes · 24h
Subscribers
3,826
active
Total calls
28
last 7 days
status Full status page → · 24 probes/24h

Pricing

Pick a tier — billed monthly, cancel anytime.

Free

Free

  • 2,000 calls / month
  • 2 requests / second
  • Hard cap (429 above quota, no overage)
  • Isentropic stagnation-to-static ratios
  • Mach-number input, single gamma
  • Deterministic JSON output
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Starter

€9.00 /month

  • 40,000 calls / month
  • 5 requests / second
  • Hard cap (429 above quota, no overage)
  • Full pressure/temperature/density/area ratios
  • Configurable specific-heat ratio gamma
  • Mach-from-ratio inverse solving
  • Email support
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Pro

€24.00 /month

  • 250,000 calls / month
  • 20 requests / second
  • Hard cap (429 above quota, no overage)
  • Batch arrays of Mach numbers per call
  • Subsonic and supercritical area-ratio branches
  • Stagnation property sweeps for nozzle design
  • Priority support
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Mega

€74.00 /month

  • 1,542,000 calls / month
  • 60 requests / second
  • Hard cap (429 above quota, no overage)
  • High-throughput nozzle/CFD pre-processing volume
  • Bulk Mach sweeps and tabulated flow curves
  • Highest rate limit for design pipelines
  • SLA-backed support
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Built by

Related APIs

Other APIs with overlapping tags.

Mach Number API

Mach-number and compressible-flow aerodynamics as an API, computed locally and deterministically. The mach endpoint computes the local speed of sound a = √(γ·R·T) (air γ = 1.4, R = 287.05 J/(kg·K)) and the Mach number M = v/a from a speed and a static temperature — given directly in °C or kelvin, or derived from a geopotential altitude through the International Standard Atmosphere (troposphere T = 288.15 − 0.0065·h up to 11 km, then the isothermal 216.65 K layer to 20 km) — and classifies the flight regime as subsonic, transonic, supersonic or hypersonic; the speed of sound is about 340.3 m/s at 15 °C and 295 m/s at 11 km. The speed endpoint inverts it, returning v = M·a in m/s, km/h and knots. The stagnation endpoint gives the isentropic total-to-static ratios T0/T = 1 + (γ−1)/2·M², P0/P = (T0/T)^(γ/(γ−1)) and ρ0/ρ = (T0/T)^(1/(γ−1)) — at Mach 2 the total pressure is about 7.82 times the static pressure — and will scale a supplied static temperature and pressure to their stagnation values. Everything is computed locally and deterministically, so it is instant and private. Ideal for aerospace, CFD, flight-simulation, wind-tunnel, UAV and aerodynamics-education app developers, compressible-flow and flight-envelope tools, and engineering software. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is compressible aerodynamics; for viscous flow and the Reynolds number use a Reynolds API and for incompressible pressure/velocity a Bernoulli API.

api.oanor.com/machnumber-api

Rocket Equation API

Rocket-propulsion maths as an API, computed locally and deterministically. The delta-v endpoint applies the Tsiolkovsky rocket equation, Δv = ve·ln(m0/mf) with the exhaust velocity ve = Isp·g0, to give the velocity change a stage can produce from its wet (fuelled) mass, dry (burnout) mass and specific impulse — the delta-v budget that determines which manoeuvres are possible. The mass-ratio endpoint inverts the equation to give the mass ratio m0/mf = exp(Δv/ve) and the propellant mass fraction required to achieve a target delta-v, and, given a dry mass, the wet mass and propellant needed — revealing the steep, exponential tyranny of the rocket equation. The burn endpoint computes the propellant mass-flow rate ṁ = thrust/ve, the burn time and the total impulse from the thrust and propellant mass, and the delta-v if the wet mass is given. Masses are in kilograms, specific impulse in seconds, exhaust velocity and delta-v in metres per second and thrust in newtons, with standard gravity g0 = 9.80665 m/s². Everything is computed locally and deterministically, so it is instant and private. Ideal for aerospace, model-rocketry, spaceflight-simulation and orbital-mission app developers, stage-sizing and trajectory tools, and physics education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is rocket propulsion; for orbital velocity and escape velocity use an orbital-mechanics API.

api.oanor.com/rocket-api

SpaceX API

Latest, next and recent SpaceX launches with mission details, success status, mission patches, webcasts and articles, a single-launch lookup by id, and the full rocket fleet with specs, success rates and imagery. Great for space dashboards, trackers, education and hobby projects.

api.oanor.com/spacex-api

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

Frequently asked questions

Quick answers about pricing, quotas, and integration.

How do I get an API key for Isentropic Flow API?
Sign up for free at oanor.com, generate an API key from the developer dashboard, and call Isentropic Flow API with the x-oanor-key header. No credit card needed for the free tier.
What's the rate limit for Isentropic Flow 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 Isentropic Flow API cost?
Isentropic Flow API has a free tier with 100 calls / month. Paid plans start at €9.00 / 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 Isentropic Flow API GDPR-compliant?
All requests to Isentropic Flow 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/isentropic-api/SOME_PATH \
  -H "x-oanor-key: oanor_test_..."
const res = await fetch("https://api.oanor.com/isentropic-api/SOME_PATH", {
  headers: { "x-oanor-key": "oanor_test_..." }
});
const data = await res.json();
$ch = curl_init("https://api.oanor.com/isentropic-api/SOME_PATH");
curl_setopt($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/isentropic-api/SOME_PATH",
    headers={"x-oanor-key": "oanor_test_..."},
)
print(r.json())

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