Critical angle (TIR)
API · /snell-api
Snell Refraction API
healthy
3,539 Subscribers
Snell's-law refraction optics as an API, computed locally and deterministically. The refraction endpoint applies Snell's law, n1·sin(θ1) = n2·sin(θ2): from the refractive indices of two media (given directly or by material — vacuum, air, water, glass, diamond and more) and the angle of incidence it returns the angle of refraction, or solves for the incidence angle from a refraction angle; when light passes into a less dense medium beyond the critical angle it reports total internal reflection instead of a refracted ray. The critical-angle endpoint gives the threshold for total internal reflection, θc = asin(n2/n1) for n1 > n2 — the principle behind optical fibres — defaulting the exit medium to air. The speed endpoint gives the speed of light in a medium, v = c/n, as a fraction of c, and — with a vacuum wavelength — the shorter wavelength inside the medium (the frequency is unchanged). Angles are in degrees, wavelengths in nanometres. Everything is computed locally and deterministically, so it is instant and private. Ideal for optics and photonics tools, fibre-optic and lens-design apps, photography and physics education, and AR/VR and rendering software. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is Snell's-law refraction; for camera depth of field and field of view use a photography API.
api.oanor.com/snell-api
API health
healthy- Uptime
- 100.00%
- Server probes · 24h
- Avg latency
- 89 ms
- Server probes · 24h
- Subscribers
- 3,539
- active
- Total calls
- 32
- 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)
- Snell's-law refraction n1·sin(θ1)=n2·sin(θ2)
- Degrees or radians input
- JSON response
- Community support
Starter
€5.00 /month
- 25,000 calls / month
- 5 requests / second
- Hard cap (429 above quota, no overage)
- Refraction angle solver
- Critical-angle & total-internal-reflection detection
- Common medium refractive-index presets
- Email support
Pro
€15.00 /month
- 150,000 calls / month
- 15 requests / second
- Hard cap (429 above quota, no overage)
- Batch ray computations
- Wavelength-aware dispersion indices
- Higher rate limits
- Priority support
Mega
€45.00 /month
- 753,000 calls / month
- 40 requests / second
- Hard cap (429 above quota, no overage)
- Bulk optics pipelines
- Full medium index library
- Max throughput for courseware & sims
- Dedicated support SLA
Built by
Related APIs
Other APIs with overlapping tags.
Prism Optics API
Optical-prism geometry as an API, computed locally and deterministically. The deviation endpoint computes the minimum deviation angle of a light ray passing through a prism of apex angle A and refractive index n, δ_min = 2·arcsin(n·sin(A/2)) − A, together with the symmetric angle of incidence and the internal refraction angle A/2 on each face — an equilateral prism (A = 60°) of crown glass (n = 1.5) deviates light by about 37.2°. The refractive-index endpoint inverts the spectrometer formula n = sin((A + δ_min)/2) / sin(A/2), the standard way a refractive index is measured from a prism’s apex angle and its measured minimum deviation. The dispersion endpoint computes the angular dispersion between two wavelengths from their refractive indices and the apex angle, and, given the three Fraunhofer indices n_F, n_C and n_D, the dispersive power ω = (n_F − n_C)/(n_D − 1) and the Abbe number V = 1/ω that quantify how strongly a glass spreads colours — crown glass has ω ≈ 0.017 and V ≈ 59. All angles are in degrees. Everything is computed locally and deterministically, so it is instant and private. Ideal for optics, spectroscopy, refractometry, photonics and physics-education app developers, lens-and-prism design tools, and lab software. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is prism geometry; for a single flat-surface refraction use a Snell’s-law API and for thin lenses a lens API.
api.oanor.com/prism-api
Angular Size API
Angular-size astronomy and optics maths as an API, computed locally and deterministically. The angular-size endpoint computes the angular diameter an object subtends, δ = 2·arctan(d/(2D)), from its physical size and its distance, returning the angle in radians, degrees, arcminutes and arcseconds, along with the small-angle approximation δ ≈ d/D — the Sun and Moon are each about half a degree (31 arcminutes) across. The distance endpoint inverts the relation, D = d/(2·tan(δ/2)), to give an object's distance from its known true size and its measured angular size, the basis of the standard-ruler distance method. The object-size endpoint computes an object's physical diameter, d = 2·D·tan(δ/2), from its distance and angular size. Size and distance use any one consistent unit, and angles may be given in radians, degrees, arcminutes or arcseconds. Everything is computed locally and deterministically, so it is instant and private. Ideal for astronomy, telescope, astrophotography, surveying and optics app developers, field-of-view and rangefinding tools, and physics education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is angular size; for stellar magnitude and parallax distance use a star-magnitude API and for sidereal time a sidereal API.
api.oanor.com/angularsize-api
Optical Fiber API
Optical-fibre photonics maths as an API, computed locally and deterministically. The numerical-aperture endpoint computes a step-index fibre's numerical aperture NA = √(n1² − n2²) from the core and cladding refractive indices, the acceptance angle θa = arcsin(NA) — the half-angle of the cone of light the fibre can capture — the full acceptance cone and the relative index difference Δ = (n1 − n2)/n1. The v-number endpoint computes the normalized frequency V = 2π·a·NA/λ from the core radius, the numerical aperture (or the indices) and the wavelength, classifies the fibre as single-mode when V is below the 2.405 cutoff or multimode above it, and gives the cutoff wavelength for single-mode operation. The modes endpoint estimates the number of guided modes — about V²/2 for a step-index fibre and V²/4 for a graded-index one — and confirms single-mode operation below the cutoff. Core radius and wavelength are in metres (1310 nm = 1.31×10⁻⁶ m) and refractive indices are dimensionless. Everything is computed locally and deterministically, so it is instant and private. Ideal for telecom, photonics, datacenter, sensor and laser app developers, fibre-link and waveguide-design tools, and optics education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is optical-fibre guiding; for thin lenses and mirrors use a lens API and for refraction at a surface a Snell API.
api.oanor.com/fiber-api
Laser Beam Optics API
Gaussian-beam laser-optics maths as an API, computed locally and deterministically. The beam endpoint propagates a Gaussian beam from its wavelength and waist radius: the Rayleigh range z_R = π·w₀²/λ and depth of focus, the divergence half- and full-angle θ = λ/(π·w₀), and — for a given distance — the beam radius and diameter w(z) = w₀·√(1+(z/z_R)²); an optional M² beam-quality factor scales it for real beams. The focus endpoint computes the diffraction-limited focused spot of a lens, w_f = λ·f/(π·w_in), with the depth of focus and the f-number, so you can size the spot a lens will deliver. The irradiance endpoint turns a beam power and spot size into the beam area and the average and on-axis peak irradiance (power density) in W/m² and W/cm². Wavelengths are in nanometres, sizes in millimetres or micrometres, distances in metres and power in watts. Everything is computed locally and deterministically, so it is instant and private. Ideal for photonics, laser-engineering, materials-processing and optics app developers, beam-delivery and laser-safety tools, and physics education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is Gaussian-beam laser optics; for refraction use a Snell API and for thin-lens imaging a lens API.
api.oanor.com/laser-api
Frequently asked questions
Quick answers about pricing, quotas, and integration.
How do I get an API key for Snell Refraction API?
Sign up for free at oanor.com, generate an API key from the developer dashboard, and call Snell Refraction API with the x-oanor-key header. No credit card needed for the free tier.
What's the rate limit for Snell Refraction 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 Snell Refraction API cost?
Snell Refraction 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 Snell Refraction API GDPR-compliant?
All requests to Snell Refraction 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/snell-api/SOME_PATH \
-H "x-oanor-key: oanor_test_..."const res = await fetch("https://api.oanor.com/snell-api/SOME_PATH", {
headers: { "x-oanor-key": "oanor_test_..." }
});
const data = await res.json();$ch = curl_init("https://api.oanor.com/snell-api/SOME_PATH");
curl_setopt($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/snell-api/SOME_PATH",
headers={"x-oanor-key": "oanor_test_..."},
)
print(r.json())Ratings
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