diff --git a/README.md b/README.md
index 089e32a..3662698 100644
--- a/README.md
+++ b/README.md
@@ -280,7 +280,7 @@ import { createEndpointQuerySchema } from '@platform/backend/query/query.ts'
 import { z } from 'zod'
 
 import { CURSOR_SECRET } from './_env.ts'
-import { BaseQuerySchema } from '#shared/server/schemas.ts'
+import { BaseQuerySchema } from '#shared/endpoint/schemas.ts'
 
 
 // 1. Declare which fields can be filtered and how
diff --git a/packages/backend/src/endpoint/definitions.ts b/packages/backend/src/endpoint/definitions.ts
new file mode 100644
index 0000000..62f9659
--- /dev/null
+++ b/packages/backend/src/endpoint/definitions.ts
@@ -0,0 +1,82 @@
+import type { ValidationTargets } from 'hono'
+import type { FormValue, ParsedFormValue } from 'hono/types'
+import type z from 'zod'
+
+/**
+ * Schema accepting input type I, producing any output
+ * 
+ * No structural constraints - accepts:
+ * - Plain objects: z.object({ ... })
+ * - Pipes: z.object({ ... }).pipe(...)
+ * - Transforms: z.object({ ... }).transform(...)
+ * - Unions, intersections, etc.
+ * 
+ * Use this when you need input type safety but want to allow transformations.
+ */
+export type SchemaFor<Input, Output = any> = z.ZodType<Output, Input>
+
+/**
+ * Helper to normalize record types for compatibility checking
+ * 
+ * Converts Record<K, V> to { [key: string]: V } to allow index signature
+ * schemas to satisfy specific key union requirements.
+ * 
+ * This enables: z.object({}).catchall(z.string()) to satisfy
+ * RecordSchemaFor<Record<RequestHeader, string>>
+ */
+type NormalizedRecordInput<T> =
+  T extends Record<infer K, infer V>
+  ? K extends string
+  ? { [key: string]: V }
+  : T
+  : T
+
+/**
+ * Schema with record-shaped input
+ * 
+ * Accepts schemas with index signatures that can parse the expected record type.
+ * This allows catchall schemas to satisfy specific key union requirements.
+ * 
+ * @example
+ * // ✓ This works - catchall accepts any string keys
+ * const schema = z.object({}).catchall(z.string())
+ *   satisfies RecordSchemaFor<Record<RequestHeader, string>>
+ */
+export type RecordSchemaFor<Input extends Record<string, any>, Output = any> =
+  SchemaFor<NormalizedRecordInput<Input>, Output>
+
+/**
+ * @deprecated Use SchemaFor<I> instead - allows transformations
+ */
+export type AnySchemaFor<I> = SchemaFor<I>
+
+/**
+ * Validation schemas for each input source
+ * 
+ * Each schema must accept the raw input type from its source:
+ * - Query: Record<string, string | string[]>
+ * - Form: Record<string, FormValue | FormValue[]>
+ * - Json: any
+ * - Param: Record<P, string | undefined>
+ * - Header: Record<RequestHeader | CustomHeader, string>
+ * - Cookie: Record<string, string>
+ * 
+ * Schemas can transform to any output type (pipes/transforms allowed).
+ */
+export type EndpointDefinitionSchemas<T extends FormValue = ParsedFormValue, P extends string = string> = {
+  [K in keyof ValidationTargets as Capitalize<K>]?:
+  ValidationTargets[K] extends Record<any, any>
+  ? RecordSchemaFor<ValidationTargets<T, P>[K]>
+  : SchemaFor<ValidationTargets<T, P>[K]>
+}
+
+// Endpoint definition contract
+export type EndpointDefinition = {
+  Name: string
+  Route: string
+  Description?: string
+  Methods: readonly ('GET' | 'POST' | 'DELETE' | 'PUT' | 'PATCH')[]
+  Input: z.ZodType
+  Output: z.ZodType
+  Schemas: EndpointDefinitionSchemas
+}
diff --git a/supabase/functions/_shared/server/schemas.ts b/packages/backend/src/endpoint/schemas.ts
similarity index 98%
rename from supabase/functions/_shared/server/schemas.ts
rename to packages/backend/src/endpoint/schemas.ts
index 5c2dac0..d73d5ad 100644
--- a/supabase/functions/_shared/server/schemas.ts
+++ b/packages/backend/src/endpoint/schemas.ts
@@ -1,6 +1,6 @@
 // schemas.ts
 import type { FormValue, ParsedFormValue } from 'hono/types';
-import type { EndpointDefinitionSchemas } from './types.ts';
+import type { EndpointDefinitionSchemas } from './definitions.ts';
 import { z } from 'zod';
 
 /**
diff --git a/packages/backend/src/query/fields.ts b/packages/backend/src/query/fields.ts
index 7da4870..623530d 100644
--- a/packages/backend/src/query/fields.ts
+++ b/packages/backend/src/query/fields.ts
@@ -13,7 +13,7 @@
 
 import { z } from 'zod'
 
-import { BaseQuerySchema, BaseJsonSchema, BaseFormSchema } from '../../../../supabase/functions/_shared/server/schemas.ts'
+import { BaseQuerySchema, BaseJsonSchema, BaseFormSchema } from '../endpoint/schemas.ts'
 import {
   FieldSelectionNormalizedSchema,
   type FieldsConfig,
diff --git a/packages/backend/src/query/filtering.ts b/packages/backend/src/query/filtering.ts
index 1c0659d..26532d7 100644
--- a/packages/backend/src/query/filtering.ts
+++ b/packages/backend/src/query/filtering.ts
@@ -132,7 +132,7 @@
 
 import { z } from 'zod'
 
-import { BaseQuerySchema, BaseJsonSchema, BaseFormSchema } from '../../../../supabase/functions/_shared/server/schemas.ts'
+import { BaseQuerySchema, BaseJsonSchema, BaseFormSchema } from '../endpoint/schemas.ts'
 import {
   FiltersNormalizedSchema,
   type FilterNormalized,
diff --git a/packages/backend/src/query/pagination.ts b/packages/backend/src/query/pagination.ts
index 70d06c5..1cf07db 100644
--- a/packages/backend/src/query/pagination.ts
+++ b/packages/backend/src/query/pagination.ts
@@ -18,7 +18,7 @@ import { z } from 'zod'
 import { createHmac } from 'node:crypto'
 import { Buffer } from 'node:buffer'
 
-import { BaseQuerySchema, BaseJsonSchema, BaseFormSchema, ZStringOrStringArray } from '../../../../supabase/functions/_shared/server/schemas.ts'
+import { BaseQuerySchema, BaseJsonSchema, BaseFormSchema, ZStringOrStringArray } from '../endpoint/schemas.ts'
 import {
   PaginationNormalizedSchema,
   CursorDataSchema,
diff --git a/packages/backend/src/query/query.ts b/packages/backend/src/query/query.ts
index 27687fa..4c42c77 100644
--- a/packages/backend/src/query/query.ts
+++ b/packages/backend/src/query/query.ts
@@ -26,7 +26,7 @@ import { createFiltersSchema } from './filtering.ts'
 import { createSortsSchema } from './sorting.ts'
 import { createFieldsSchema } from './fields.ts'
 
-import { BaseFormSchema, BaseJsonSchema, BaseQuerySchema } from '../../../../supabase/functions/_shared/server/schemas.ts'
+import { BaseFormSchema, BaseJsonSchema, BaseQuerySchema } from '../endpoint/schemas.ts'
 
 // Re-export QuerySpec type
 export { QuerySpecSchema, type QuerySpec } from './schemas.ts'
diff --git a/packages/backend/src/query/sorting.ts b/packages/backend/src/query/sorting.ts
index 538b8fe..9aa7b63 100644
--- a/packages/backend/src/query/sorting.ts
+++ b/packages/backend/src/query/sorting.ts
@@ -12,7 +12,7 @@
 
 import { z } from 'zod'
 
-import { BaseQuerySchema, BaseJsonSchema, BaseFormSchema, ZStringOrStringArray } from '../../../../supabase/functions/_shared/server/schemas.ts'
+import { BaseQuerySchema, BaseJsonSchema, BaseFormSchema, ZStringOrStringArray } from '../endpoint/schemas.ts'
 import {
   SortsNormalizedSchema,
   type SortNormalized,
diff --git a/supabase/functions/_shared/server/types.ts b/supabase/functions/_shared/server/types.ts
index 9926315..2b56786 100644
--- a/supabase/functions/_shared/server/types.ts
+++ b/supabase/functions/_shared/server/types.ts
@@ -1,86 +1,11 @@
 import type { AppEnv as SharedAppEnv } from './create-app.ts'
-import type { Handler, MiddlewareHandler, ValidationTargets, Input } from 'hono'
-import type { FormValue, HandlerResponse, ParsedFormValue } from 'hono/types'
+import type { Handler, MiddlewareHandler, Input } from 'hono'
+import type { HandlerResponse } from 'hono/types'
 import type z from 'zod'
 
-/**
- * Schema accepting input type I, producing any output
- * 
- * No structural constraints - accepts:
- * - Plain objects: z.object({ ... })
- * - Pipes: z.object({ ... }).pipe(...)
- * - Transforms: z.object({ ... }).transform(...)
- * - Unions, intersections, etc.
- * 
- * Use this when you need input type safety but want to allow transformations.
- */
-export type SchemaFor<Input, Output = any> = z.ZodType<Output, Input>
-
-/**
- * Helper to normalize record types for compatibility checking
- * 
- * Converts Record<K, V> to { [key: string]: V } to allow index signature
- * schemas to satisfy specific key union requirements.
- * 
- * This enables: z.object({}).catchall(z.string()) to satisfy
- * RecordSchemaFor<Record<RequestHeader, string>>
- */
-type NormalizedRecordInput<T> =
-  T extends Record<infer K, infer V>
-  ? K extends string
-  ? { [key: string]: V }
-  : T
-  : T
-
-/**
- * Schema with record-shaped input
- * 
- * Accepts schemas with index signatures that can parse the expected record type.
- * This allows catchall schemas to satisfy specific key union requirements.
- * 
- * @example
- * // ✓ This works - catchall accepts any string keys
- * const schema = z.object({}).catchall(z.string())
- *   satisfies RecordSchemaFor<Record<RequestHeader, string>>
- */
-export type RecordSchemaFor<Input extends Record<string, any>, Output = any> =
-  SchemaFor<NormalizedRecordInput<Input>, Output>
-
-/**
- * @deprecated Use SchemaFor<I> instead - allows transformations
- */
-export type AnySchemaFor<I> = SchemaFor<I>
-
-/**
- * Validation schemas for each input source
- * 
- * Each schema must accept the raw input type from its source:
- * - Query: Record<string, string | string[]>
- * - Form: Record<string, FormValue | FormValue[]>
- * - Json: any
- * - Param: Record<P, string | undefined>
- * - Header: Record<RequestHeader | CustomHeader, string>
- * - Cookie: Record<string, string>
- * 
- * Schemas can transform to any output type (pipes/transforms allowed).
- */
-export type EndpointDefinitionSchemas<T extends FormValue = ParsedFormValue, P extends string = string> = {
-  [K in keyof ValidationTargets as Capitalize<K>]?:
-  ValidationTargets[K] extends Record<any, any>
-  ? RecordSchemaFor<ValidationTargets<T, P>[K]>
-  : SchemaFor<ValidationTargets<T, P>[K]>
-}
+import type { EndpointDefinition, EndpointDefinitionSchemas } from '@platform/backend/endpoint/definitions.ts'
+export type * from '@platform/backend/endpoint/definitions.ts'
 
-// Endpoint definition contract
-export type EndpointDefinition = {
-  Name: string
-  Route: string
-  Description?: string
-  Methods: readonly ('GET' | 'POST' | 'DELETE' | 'PUT' | 'PATCH')[]
-  Input: z.ZodType
-  Output: z.ZodType
-  Schemas: EndpointDefinitionSchemas
-}
 
 /**
  * FunctionAppEnv with specific variable requirements.
diff --git a/supabase/functions/social/endpoints/follows/check/definition.ts b/supabase/functions/social/endpoints/follows/check/definition.ts
index fdee08a..b0f1576 100644
--- a/supabase/functions/social/endpoints/follows/check/definition.ts
+++ b/supabase/functions/social/endpoints/follows/check/definition.ts
@@ -12,7 +12,7 @@
 import type { EndpointDefinition } from '#shared/server/types.ts'
 
 import { makeSuccessResponseSchema } from '@platform/backend/response/schemas.ts'
-import { BaseQuerySchema } from '#shared/server/schemas.ts'
+import { BaseQuerySchema } from '@platform/backend/endpoint/schemas.ts'
 import { FollowPreferencesSchema } from '../../../utils/_schemas.ts'
 import { z } from 'zod'
 
diff --git a/supabase/functions/social/endpoints/follows/follow/definition.ts b/supabase/functions/social/endpoints/follows/follow/definition.ts
index 87e0f3f..f79ce0b 100644
--- a/supabase/functions/social/endpoints/follows/follow/definition.ts
+++ b/supabase/functions/social/endpoints/follows/follow/definition.ts
@@ -16,7 +16,7 @@
 import type { EndpointDefinition } from '#shared/server/types.ts'
 
 import { makeSuccessResponseSchema } from '@platform/backend/response/schemas.ts'
-import { BaseJsonSchema } from '#shared/server/schemas.ts'
+import { BaseJsonSchema } from '@platform/backend/endpoint/schemas.ts'
 import { FollowPreferencesSchema, FollowItemSchema } from '../../../utils/_schemas.ts'
 import { z } from 'zod'
 
diff --git a/supabase/functions/social/endpoints/follows/list/definition.ts b/supabase/functions/social/endpoints/follows/list/definition.ts
index 7fa197a..e0f6676 100644
--- a/supabase/functions/social/endpoints/follows/list/definition.ts
+++ b/supabase/functions/social/endpoints/follows/list/definition.ts
@@ -16,7 +16,7 @@ import type { EndpointDefinition } from '#shared/server/types.ts'
 import { makePaginationResultSchema } from '@platform/backend/response/schemas.ts'
 import { createEndpointQuerySchema } from '@platform/backend/query/query.ts'
 
-import { BaseQuerySchema } from '#shared/server/schemas.ts'
+import { BaseQuerySchema } from '@platform/backend/endpoint/schemas.ts'
 import { FollowItemSchema } from '../../../utils/_schemas.ts'
 import { CURSOR_SECRET } from './_env.ts'
 import { z } from 'zod'
diff --git a/supabase/functions/social/endpoints/follows/unfollow/definition.ts b/supabase/functions/social/endpoints/follows/unfollow/definition.ts
index ea98e56..0acb52b 100644
--- a/supabase/functions/social/endpoints/follows/unfollow/definition.ts
+++ b/supabase/functions/social/endpoints/follows/unfollow/definition.ts
@@ -15,7 +15,7 @@
 import type { EndpointDefinition } from '#shared/server/types.ts'
 
 import { makeSuccessResponseSchema } from '@platform/backend/response/schemas.ts'
-import { BaseQuerySchema, BaseParamSchema } from '#shared/server/schemas.ts'
+import { BaseQuerySchema, BaseParamSchema } from '@platform/backend/endpoint/schemas.ts'
 import { z } from 'zod'
 
 // ============================================================================
diff --git a/supabase/functions/social/endpoints/follows/update/definition.ts b/supabase/functions/social/endpoints/follows/update/definition.ts
index 4ed4f0c..e64b66a 100644
--- a/supabase/functions/social/endpoints/follows/update/definition.ts
+++ b/supabase/functions/social/endpoints/follows/update/definition.ts
@@ -14,7 +14,7 @@
 import type { EndpointDefinition } from '#shared/server/types.ts'
 
 import { makeSuccessResponseSchema } from '@platform/backend/response/schemas.ts'
-import { BaseJsonSchema, BaseParamSchema } from '#shared/server/schemas.ts'
+import { BaseJsonSchema, BaseParamSchema } from '@platform/backend/endpoint/schemas.ts'
 import { FollowPreferencesSchema, FollowItemSchema } from '../../../utils/_schemas.ts'
 import { z } from 'zod'
 
diff --git a/supabase/functions/social/endpoints/likes/check/definition.ts b/supabase/functions/social/endpoints/likes/check/definition.ts
index 4906df3..78586a2 100644
--- a/supabase/functions/social/endpoints/likes/check/definition.ts
+++ b/supabase/functions/social/endpoints/likes/check/definition.ts
@@ -1,7 +1,7 @@
 // endpoint/likes/check/definition.ts
 import type { EndpointDefinition } from '#shared/server/types.ts'
 
-import { BaseQuerySchema } from '#shared/server/schemas.ts'
+import { BaseQuerySchema } from '@platform/backend/endpoint/schemas.ts'
 import { z } from 'zod'
 
 export const QuerySchema = BaseQuerySchema.extend({
diff --git a/supabase/functions/social/endpoints/likes/like/definition.ts b/supabase/functions/social/endpoints/likes/like/definition.ts
index d060d32..dac1346 100644
--- a/supabase/functions/social/endpoints/likes/like/definition.ts
+++ b/supabase/functions/social/endpoints/likes/like/definition.ts
@@ -2,7 +2,7 @@
 import type { EndpointDefinition } from '#shared/server/types.ts'
 
 import { makeSuccessResponseSchema } from '@platform/backend/response/schemas.ts'
-import { BaseJsonSchema } from '#shared/server/schemas.ts'
+import { BaseJsonSchema } from '@platform/backend/endpoint/schemas.ts'
 import { z } from 'zod'
 
 export const JsonSchema = z.object({
diff --git a/supabase/functions/social/endpoints/likes/list/definition.ts b/supabase/functions/social/endpoints/likes/list/definition.ts
index 9f931bb..e7d5530 100644
--- a/supabase/functions/social/endpoints/likes/list/definition.ts
+++ b/supabase/functions/social/endpoints/likes/list/definition.ts
@@ -5,7 +5,7 @@ import type { EndpointDefinition } from '#shared/server/types.ts'
 import { makePaginationResultSchema } from '@platform/backend/response/schemas.ts'
 import { createEndpointQuerySchema } from '@platform/backend/query/query.ts'
 
-import { BaseQuerySchema } from '#shared/server/schemas.ts'
+import { BaseQuerySchema } from '@platform/backend/endpoint/schemas.ts'
 import { CURSOR_SECRET } from './_env.ts'
 import { z } from 'zod'
 
diff --git a/supabase/functions/social/endpoints/likes/unlike/definition.ts b/supabase/functions/social/endpoints/likes/unlike/definition.ts
index d901a95..61a5f22 100644
--- a/supabase/functions/social/endpoints/likes/unlike/definition.ts
+++ b/supabase/functions/social/endpoints/likes/unlike/definition.ts
@@ -1,7 +1,7 @@
 // endpoint/likes/unlike/definition.ts
 import { z } from 'zod'
 import type { EndpointDefinition } from '#shared/server/types.ts'
-import { BaseQuerySchema, BaseParamSchema } from '#shared/server/schemas.ts'
+import { BaseQuerySchema, BaseParamSchema } from '@platform/backend/endpoint/schemas.ts'
 
 export const Route = '/likes/:target_id';
 export const ParamSchema = BaseParamSchema.extend({