Electric field of a point charge
API · /coulomb-api
Coulomb & Electric Field API
healthy
3,359 Subscribers
Coulomb's-law electrostatics as an API, computed locally and deterministically. The force endpoint computes the electrostatic force between two point charges, F = k·q1·q2/(εr·r²) — Coulomb's law, with k = 8.9876×10⁹ N·m²/C² — from the two charges, their separation and an optional relative permittivity for a dielectric medium, and tells you whether the force is attractive (opposite signs) or repulsive (like signs). The field endpoint gives the electric field of a point charge, E = k·q/(εr·r²), its direction (away from a positive charge, toward a negative one), and the force on a test charge placed there, F = q_test·E. The potential endpoint gives the electric potential V = k·q/(εr·r) and, for a pair of charges, the electrostatic potential energy U = k·q1·q2/(εr·r) in joules and electron-volts. Charges may be entered in coulombs, microcoulombs or nanocoulombs. Everything is computed locally and deterministically, so it is instant and private. Ideal for physics and electrical-engineering education tools, electrostatics and field-theory apps, and laboratory and simulation software. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is electrostatics; for Ohm's law and DC/AC circuits use an Ohm's-law API.
api.oanor.com/coulomb-api
API health
healthy- Uptime
- 100.00%
- Server probes · 24h
- Avg latency
- 78 ms
- Server probes · 24h
- Subscribers
- 3,359
- 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)
- Coulomb force between two point charges
- SI units (N, C, m) with vacuum permittivity
- JSON request/response
- Community support
Starter
€5.00 /month
- 25,000 calls / month
- 5 requests / second
- Hard cap (429 above quota, no overage)
- Force + electric-field magnitude endpoints
- Custom relative permittivity (dielectric medium)
- Worked-out formula breakdown in response
- Email support
Pro
€15.00 /month
- 150,000 calls / month
- 15 requests / second
- Hard cap (429 above quota, no overage)
- Multi-charge superposition fields
- Vector field components (Ex, Ey, Ez)
- Potential energy + potential endpoints
- Higher rate limit for classroom apps
Mega
€49.00 /month
- 765,000 calls / month
- 40 requests / second
- Hard cap (429 above quota, no overage)
- Unlimited charge-configuration batches
- Field-line and equipotential sampling output
- Priority compute lane
- Priority support + SLA
Built by
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api.oanor.com/hotairballoon-api
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api.oanor.com/vacuum-api
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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 Coulomb & Electric Field API?
Sign up for free at oanor.com, generate an API key from the developer dashboard, and call Coulomb & Electric Field API with the x-oanor-key header. No credit card needed for the free tier.
What's the rate limit for Coulomb & Electric Field 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 Coulomb & Electric Field API cost?
Coulomb & Electric Field 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 Coulomb & Electric Field API GDPR-compliant?
All requests to Coulomb & Electric Field 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/coulomb-api/SOME_PATH \
-H "x-oanor-key: oanor_test_..."const res = await fetch("https://api.oanor.com/coulomb-api/SOME_PATH", {
headers: { "x-oanor-key": "oanor_test_..." }
});
const data = await res.json();$ch = curl_init("https://api.oanor.com/coulomb-api/SOME_PATH");
curl_setopt($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/coulomb-api/SOME_PATH",
headers={"x-oanor-key": "oanor_test_..."},
)
print(r.json())Ratings
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