TypeScript-first schema validation and type inference. Use for validating API requests/responses, form data, env vars, configs, defining type-safe schemas with runtime validation, transforming data, generating JSON Schema for OpenAPI/AI, or encountering missing validation errors, type inference issues, validation error handling problems. Zero dependencies (2kb gzipped).
91
92%
Does it follow best practices?
Impact
88%
2.51xAverage score across 3 eval scenarios
Passed
No known issues
Codec-based bidirectional API schemas
Uses z.codec()
0%
100%
Uses z.iso.datetime()
0%
100%
Decode function defined
0%
100%
Encode function defined
0%
100%
Uses .meta() for fields
0%
100%
z.toJSONSchema() called
0%
100%
OpenAPI target option
0%
100%
metadata: true option
0%
0%
z.infer used for types
100%
100%
Demo uses .decode()
0%
100%
Demo uses .encode()
0%
100%
Error handling and safeParse patterns
Uses .safeParse()
100%
100%
z.flattenError() used
0%
100%
z.treeifyError() used
0%
100%
z.prettifyError() used
0%
70%
Optional chaining on tree
50%
100%
Unified error parameter
0%
50%
z.discriminatedUnion() used
0%
0%
z.infer for types
100%
100%
Localization configured
20%
100%
No deprecated methods
0%
100%
Zod v3 to v4 API migration
.extend() replaces .merge()
100%
100%
Unified error parameter
0%
100%
z.flattenError() replaces error.flatten()
100%
100%
z.treeifyError() replaces error.format()
33%
100%
.implement() replaces .parse()
100%
100%
z.enum() replaces z.nativeEnum()
100%
100%
z.infer replaces manual type
100%
100%
discriminatedUnion replaces union
0%
0%
Top-level format validators
100%
100%
migration-notes.md created
100%
100%
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Table of Contents
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