TypeScript Zod to OpenAI Schema

Zod is a TypeScript-first schema validation library. Learn how to use Zod schemas with OpenAI's Structured Outputs for type-safe AI responses.

Why Zod for OpenAI?

• TypeScript-native with excellent type inference
• Runtime validation of AI responses
• Convert to JSON Schema with zod-to-json-schema
• Works with OpenAI's Node.js SDK

Strict Mode with Zod

Use .strict() to ensure the schema is compatible with OpenAI's strict mode:

import { z } from 'zod';
import { zodToJsonSchema } from 'zod-to-json-schema';

const UserSchema = z.object({
  name: z.string(),
  email: z.string().email(),
  age: z.number().int(),
}).strict(); // Important for OpenAI strict mode

const jsonSchema = zodToJsonSchema(UserSchema);

Using with OpenAI SDK

import OpenAI from 'openai';
import { z } from 'zod';
import { zodToJsonSchema } from 'zod-to-json-schema';

const ResponseSchema = z.object({
  summary: z.string(),
  sentiment: z.enum(['positive', 'negative', 'neutral']),
  confidence: z.number(),
}).strict();

const client = new OpenAI();

const response = await client.chat.completions.create({
  model: 'gpt-4o-2024-08-06',
  messages: [{ role: 'user', content: '...' }],
  response_format: {
    type: 'json_schema',
    json_schema: {
      name: 'Analysis',
      strict: true,
      schema: zodToJsonSchema(ResponseSchema)
    }
  }
});

// Parse and validate response
const parsed = ResponseSchema.parse(
  JSON.parse(response.choices[0].message.content)
);

Benefits of This Approach