Relativistic energy
API · /relativity-api
Special Relativity API
healthy
4,281 Subscribers
Special-relativity maths as an API, computed locally and deterministically. The lorentz endpoint computes the Lorentz factor γ = 1/√(1 − β²) from a velocity (in m/s, km/s or as a fraction of the speed of light β), and — given a proper time or a proper length — the dilated time Δt = γ·Δt₀ that a stationary observer measures and the contracted length L = L₀/γ. The energy endpoint computes the rest energy E₀ = mc², the total energy E = γmc², the kinetic energy KE = (γ − 1)mc² and the relativistic momentum p = γmv of a mass moving at a given speed, reporting the energies in both joules and electronvolts. The mass-energy endpoint applies Einstein's E = mc² to convert between mass and energy in either direction, in joules, electronvolts, megaelectronvolts and kilowatt-hours. The speed of light is exactly 299,792,458 m/s. Everything is computed locally and deterministically, so it is instant and private. Ideal for physics-education, simulation, astronomy and science-communication app developers, relativity and particle-physics tools, and STEM teaching. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is special relativity; for everyday SUVAT motion use a kinematics API and for orbital mechanics an orbital API.
api.oanor.com/relativity-api
API health
healthy- Uptime
- 100.00%
- Server probes · 24h
- Avg latency
- 75 ms
- Server probes · 24h
- Subscribers
- 4,281
- active
- Total calls
- 76
- last 7 days
Pricing
Pick a tier — billed monthly, cancel anytime.
Free
Free
- 2,000 calls / month
- 2 requests / second
- Hard cap (429 above quota, no overage)
- Lorentz factor gamma from velocity (beta input)
- Deterministic, instant local compute
- 2000 calls/month to evaluate
Starter
€5.00 /month
- 20,000 calls / month
- 5 requests / second
- Hard cap (429 above quota, no overage)
- Lorentz factor + time-dilation maths
- 20k calls/month for coursework & demos
- JSON responses with full precision
- Email support
Pro
€15.00 /month
- 150,000 calls / month
- 15 requests / second
- Hard cap (429 above quota, no overage)
- All special-relativity endpoints
- 150k calls/month for classroom apps
- Length-contraction & relativistic energy
- Higher 15 rps throughput
Mega
€49.00 /month
- 1,000,000 calls / month
- 40 requests / second
- Hard cap (429 above quota, no overage)
- 1M calls/month for high-traffic ed-tech
- Mass-energy & momentum endpoints
- 40 rps burst capacity
- Priority support & SLA
Built by
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Atomic isotope reference data as an API, built on the NIST Atomic Weights and Isotopic Compositions. For every known nuclide: its element (atomic number Z and symbol), mass number, relative atomic mass, natural isotopic composition (abundance) and the element's standard atomic weight. Look an isotope up by label (C-12, U-238) or by symbol + mass, list every isotope of an element, rank isotopes by mass or natural abundance, or search. A precise physics and chemistry reference for science, education, lab and engineering apps. Distinct from element-level data.
api.oanor.com/isotopes-api
Hot Air Balloon Lift API
Hot-air-balloon lift maths as an API, computed locally and deterministically — the thermal-lift, envelope-temperature and air-density numbers a balloon pilot, designer or physics teacher works a flight out with. The lift endpoint gives the buoyant lift from heating the air: gross lift = envelope volume × (outside air density − inside air density), the densities from the ideal-gas law — a 2,500 m³ envelope at 100 °C on a 15 °C day lifts about 698 kg gross, from which you subtract the envelope, basket, burner and fuel for the payload, and the hotter the air and colder the day the more it lifts. The required-temp endpoint inverts it: to carry a target lift the inside air must reach a particular density and so a particular temperature, with a check that it stays under the ~120 °C that nylon envelopes can take — the everyday pre-flight question of whether the balloon can lift today's crew and fuel. The air-density endpoint gives the moist-air density ρ = (P − 0.378·Pv) ÷ (R·T), and explains the counter-intuitive fact that humid air is LESS dense than dry air, slightly cutting the lift. Everything is computed locally and deterministically, so it is instant and private. Ideal for ballooning and aviation tools, STEM and physics-education apps, and buoyancy calculators. Pure local computation — no key, no third-party service, instant. Idealised dry-lift model. 3 compute endpoints. For Archimedes flotation in water use a buoyancy API; for party-balloon helium lift a balloon API.
api.oanor.com/hotairballoon-api
Vacuum Technology API
Vacuum-technology maths as an API, computed locally and deterministically — the pump-down, boiling and pressure numbers a lab tech, process engineer or vacuum hobbyist works to. The pumpdown endpoint gives the ideal time to evacuate a chamber, t = (volume ÷ pump speed) × ln(start ÷ target pressure) — a 10-litre chamber on a 5 L/s pump drops from 1000 to 1 mbar in about 14 seconds in theory, though outgassing and falling pump speed stretch the real low-pressure stage. The boiling-point endpoint gives the temperature water boils at under reduced pressure from the Antoine equation: about 100 °C at sea level, but only ~52 °C at 100 mbar and ~46 °C at 100 mbar — the physics behind vacuum degassing, freeze-drying and high-altitude cooking. The level endpoint converts a pressure across the common vacuum units (mbar, Torr/mmHg, Pa, kPa, inHg, atm, psi), reports the percent vacuum relative to atmosphere, and names the regime — rough, medium, high or ultra-high vacuum — so you know which pump and gauge the job needs. Everything is computed locally and deterministically, so it is instant and private. Ideal for vacuum-lab and process apps, pump-sizing and degassing tools, semiconductor and coating calculators, and physics teaching. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 compute endpoints. Ideal estimates — real systems are slowed by outgassing and leaks.
api.oanor.com/vacuum-api
Center of Mass API
Centre-of-mass and barycentre mechanics as an API, computed locally and deterministically. The point-masses endpoint computes the centre of mass of a system of point masses in one, two or three dimensions, applying x_com = Σ(m_i·x_i)/Σm_i to each axis from a list of masses and their x (and optional y and z) coordinates — masses of 1, 2 and 3 at positions 0, 1 and 2 give a centre of mass at 1.333, and four equal masses at the corners of a square sit at its centre. The two-body endpoint computes the barycentre of two masses separated by a distance, r1 = d·m2/(m1+m2) from the first body, which always lies closer to the heavier one — for the Earth-Moon system the barycentre is about 4 670 km from Earth’s centre, still inside the planet. Lists may be passed as comma-separated values (masses=1,2,3&x=0,1,2) or as JSON arrays in a POST body, and units are consistent and unit-agnostic. Everything is computed locally and deterministically, so it is instant and private. Ideal for physics, engineering-statics, astronomy, robotics, game-physics and mechanics-education app developers, balance-point and barycentre tools, and simulation software. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 2 endpoints. This is the centre of mass; for the rotational moment of inertia use a moment-of-inertia API.
api.oanor.com/centerofmass-api
Frequently asked questions
Quick answers about pricing, quotas, and integration.
How do I get an API key for Special Relativity API?
Sign up for free at oanor.com, generate an API key from the developer dashboard, and call Special Relativity API with the x-oanor-key header. No credit card needed for the free tier.
What's the rate limit for Special Relativity 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 Special Relativity API cost?
Special Relativity 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 Special Relativity API GDPR-compliant?
All requests to Special Relativity 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/relativity-api/SOME_PATH \
-H "x-oanor-key: oanor_test_..."const res = await fetch("https://api.oanor.com/relativity-api/SOME_PATH", {
headers: { "x-oanor-key": "oanor_test_..." }
});
const data = await res.json();$ch = curl_init("https://api.oanor.com/relativity-api/SOME_PATH");
curl_setopt($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/relativity-api/SOME_PATH",
headers={"x-oanor-key": "oanor_test_..."},
)
print(r.json())Ratings
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