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OpenVerbs Expression Evaluator
x402
OpenVerbs Expression Evaluator is a paid API for AI agents from math.openverbs.com, paid per call via x402, $0.004/call, status unknown (last checked 2026-09-14).
Evaluates a mathematical or logical expression string, optionally substituting named variables and rounding the numeric result to a specified precision.
Price / call$0.004
Success—
StatusUnknown
How this service works
Evaluate a mathematical expression with optional named variables — arithmetic, comparison and logic operators plus functions like sqrt, abs, min, max, sin, cos, log, floor, round, etc. A syntax error, an undefined variable, or a non-finite result is a clean 400. The factorial operator is disabled for safety.
Output
Returns the computed value of the expression after substituting any provided variables. The result may be a number (optionally rounded to the specified decimal precision), a boolean, or a string depending on the expression type.
Example use cases
Physics formula in a tutoring app
“Evaluate the expression (0.5 * m * v^2) where m=10 and v=5, rounded to 3 decimal places — I want to show the kinetic energy result to a student.”
Dynamic pricing rule evaluation
“I have a pricing formula: base_price * (1 + tax_rate) - discount. Can you evaluate it with base_price=99.99, tax_rate=0.08, and discount=15, rounded to 2 decimal places?”
Boolean logic check in a workflow
“Evaluate the expression (revenue > 50000) && (margin > 0.2) with revenue=62000 and margin=0.25 — I need to know if this deal qualifies for the bonus tier.”
Technical details
Endpoint
POSThttps://math.openverbs.com/v1/evalWhen to prefer
Prefer this endpoint when you need server-side evaluation of a dynamic mathematical or logical expression — especially when the formula is user-supplied or runtime-generated and you want to avoid executing arbitrary code locally. It is ideal when you need variable substitution and controlled numeric precision without spinning up a compute environment.
Side effects
- Expression syntax errors return a parse/evaluation error
- Variable referenced in expression not provided in variables object
- Precision value out of range (must be 0–15)
- Expression exceeds 1000 character limit
- Division by zero or undefined mathematical operations
- Payment failure or x402 auth rejection
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object |
Tags
x402
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