Implementation:Langfuse Langfuse Model Pricing Validation

Knowledge Sources	Langfuse
Domains	Model Pricing, Validation, Zod Schemas
Last Updated	2026-02-14 00:00 GMT

Overview

Provides shared validation logic and Zod schemas for model pricing tiers, including regex pattern safety validation, individual tier input validation, and cross-tier consistency validation.

Description

This module defines the validation layer for the model pricing tiers feature. It is shared between the Public API and tRPC routes to ensure consistent validation across all entry points.

Regex Pattern Validation (validateRegexPattern): Validates a regex pattern string through three checks: length (max 200 characters), syntax validity (via new RegExp()), and safety against catastrophic backtracking (via the safe-regex2 library). Throws descriptive errors for each failure case.

Zod Schemas:

• PricingTierConditionSchema: Validates a single condition with a regex usage detail pattern (validated for safety), a comparison operator (gt, gte, lt, lte, eq, neq), a non-negative numeric value, and an optional case sensitivity flag (defaults to false).
• PricingTierInputSchema: Validates a full pricing tier with name (1-100 chars), isDefault flag, priority (integer 0-999), conditions array, and a prices record mapping usage type strings to non-negative numbers.

Cross-Tier Validation (validatePricingTiers): Validates an array of pricing tiers ensuring: at least one tier exists, exactly one default tier, default tier has priority 0 with empty conditions, non-default tiers have at least one condition, unique priorities, unique names, all regex patterns are valid, all tiers have at least one price, and all tiers share the same usage keys as the default tier.

Pricing Method Validation (validatePricingMethod): Validates mutual exclusivity between flat pricing (inputPrice/outputPrice/totalPrice) and tiered pricing, ensuring exactly one method is used.

Usage

Use these schemas and validation functions when creating or updating model definitions with pricing information, both in the public API endpoint handlers and in the tRPC mutation resolvers. The validatePricingTiers function should be called after individual tier validation to enforce cross-tier business rules.

Code Reference

Source Location

• Repository: Langfuse
• File: packages/shared/src/features/model-pricing/validation.ts
• Lines: 1-251

Signature

export function validateRegexPattern(pattern: string): void;

export const PricingTierConditionSchema: z.ZodObject<{
  usageDetailPattern: z.ZodString;
  operator: z.ZodEnum<["gt", "gte", "lt", "lte", "eq", "neq"]>;
  value: z.ZodNumber;
  caseSensitive: z.ZodBoolean;
}>;

export type PricingTierCondition = z.infer<typeof PricingTierConditionSchema>;

export const PricingTierInputSchema: z.ZodObject<{
  name: z.ZodString;
  isDefault: z.ZodBoolean;
  priority: z.ZodNumber;
  conditions: z.ZodArray<typeof PricingTierConditionSchema>;
  prices: z.ZodRecord<z.ZodString, z.ZodNumber>;
}>;

export type PricingTierInput = z.infer<typeof PricingTierInputSchema>;

export function validatePricingTiers(
  tiers: PricingTierInput[],
): { valid: true } | { valid: false; error: string };

export function validatePricingMethod(params: {
  hasFlatPrices: boolean;
  hasPricingTiers: boolean;
}): { valid: true } | { valid: false; error: string };

Import

import {
  validateRegexPattern,
  PricingTierConditionSchema,
  PricingTierInputSchema,
  validatePricingTiers,
  validatePricingMethod,
} from "@langfuse/shared/src/features/model-pricing/validation";

I/O Contract

Inputs

Name	Type	Required	Description
pattern	string	Yes	Regex pattern string to validate (for validateRegexPattern).
tiers	PricingTierInput[]	Yes	Array of pricing tier inputs to validate (for validatePricingTiers).
hasFlatPrices	boolean	Yes	Whether flat pricing fields are provided (for validatePricingMethod).
hasPricingTiers	boolean	Yes	Whether pricing tiers are provided (for validatePricingMethod).

Outputs

Name	Type	Description
validateRegexPattern	void	Returns nothing on success; throws Error with descriptive message on failure.
validatePricingTiers	{ valid: false; error: string }	Validation result with error message if invalid.
validatePricingMethod	{ valid: false; error: string }	Validation result ensuring mutual exclusivity of pricing methods.

Usage Examples

import { validatePricingTiers, PricingTierInputSchema } from "@langfuse/shared/src/features/model-pricing/validation";

const tiers = [
  {
    name: "Default",
    isDefault: true,
    priority: 0,
    conditions: [],
    prices: { input: 0.001, output: 0.002 },
  },
  {
    name: "High Context",
    isDefault: false,
    priority: 1,
    conditions: [{ usageDetailPattern: "input.*", operator: "gt" as const, value: 100000, caseSensitive: false }],
    prices: { input: 0.0005, output: 0.0015 },
  },
];

const result = validatePricingTiers(tiers);
if (!result.valid) {
  console.error(result.error);
}