# Sindri Physical Constants Lookup

> Sindri Physical Constants Lookup is a paid API for AI agents from ppu43fkyhimq5fiqpmo42eh5ri0yypid.lambda-url.us-east-1.on.aws, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-20).

Returns exact CODATA-published values for eight fundamental physical constants given a constant name enum.

## Facts

- Endpoint: POST https://ppu43fkyhimq5fiqpmo42eh5ri0yypid.lambda-url.us-east-1.on.aws/physicalConstants?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-20
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/sindri-physical-constants-lookup-06bd6d63
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_tLk6-4Vi1WRmKwRl_S7BX

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability sindri-physical-constants-lookup-06bd6d63 -d '<json body>'
```

Example prompt: What's the exact CODATA value of the Boltzmann constant? Use the physical constants lookup for boltzmannConstant.

## When to prefer this

Use this endpoint when you need authoritative, exact CODATA values for fundamental physical constants rather than relying on an LLM's memorized (and potentially imprecise) training data. Ideal for scientific calculations, unit conversions, or any workflow requiring high-precision constant values.

## Known failure modes

- Invalid or unsupported constant name returns an error — only the eight enumerated constants are supported
- Malformed request body (missing 'constant' field) returns a validation error
- Lambda cold start may add latency on first call
- Payment failure or insufficient USDC balance blocks the request

## How this service works

Lookup of standard physical constants (speed of light, gravitational constant, Planck constant, elementary charge, Avogadro number, Boltzmann constant, gas constant, electron mass) with exact published CODATA values.

## Output

Returns the exact CODATA-published numeric value and unit for the requested physical constant (e.g. speed of light: 299792458 m/s, gravitational constant: 6.67430e-11 N⋅m²/kg²).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "constant": {
   "enum": [
    "speedOfLight",
    "gravitationalConstant",
    "planckConstant",
    "elementaryCharge",
    "avogadroNumber",
    "boltzmannConstant",
    "gasConstant",
    "electronMass"
   ],
   "type": "string",
   "description": "Which constant to look up."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/sindri-physical-constants-lookup-06bd6d63/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from ppu43fkyhimq5fiqpmo42eh5ri0yypid.lambda-url.us-east-1.on.aws](https://www.zero.xyz/host/ppu43fkyhimq5fiqpmo42eh5ri0yypid.lambda-url.us-east-1.on.aws/llms.txt)