diff --git a/integration-test/langfuse-integration-node.spec.ts b/integration-test/langfuse-integration-node.spec.ts
index f8103931..d65c0597 100644
--- a/integration-test/langfuse-integration-node.spec.ts
+++ b/integration-test/langfuse-integration-node.spec.ts
@@ -432,6 +432,26 @@ describe("Langfuse Node.js", () => {
         version: expect.any(Number),
       });
     });
+
+    it("update a prompt", async () => {
+      const promptName = "test-prompt" + Math.random().toString(36);
+      await langfuse.createPrompt({
+        name: promptName,
+        prompt: "This is a prompt with a {{variable}}",
+        isActive: true,
+        labels: ["john"],
+      });
+
+      const updatedPrompt = await langfuse.updatePrompt({
+        name: promptName,
+        version: 1,
+        newLabels: ["john", "doe"],
+      });
+
+      const prompt = await langfuse.getPrompt(promptName);
+      expect(prompt.labels).toEqual(expect.arrayContaining(["john", "doe"]));
+      expect(updatedPrompt.labels).toEqual(expect.arrayContaining(["john", "doe"]));
+    });
   });
 
   it("link prompt to generation", async () => {
diff --git a/langfuse-core/openapi-spec/openapi-server.yaml b/langfuse-core/openapi-spec/openapi-server.yaml
index 9e40794a..bb6c7fad 100644
--- a/langfuse-core/openapi-spec/openapi-server.yaml
+++ b/langfuse-core/openapi-spec/openapi-server.yaml
@@ -723,6 +723,9 @@ paths:
         Notes:
 
 
+        - Introduction to data model:
+        https://langfuse.com/docs/tracing-data-model
+
         - Batch sizes are limited to 3.5 MB in total. You need to adjust the
         number of events per batch accordingly.
 
@@ -1423,6 +1426,76 @@ paths:
               schema: {}
       security:
         - BasicAuth: []
+  /api/public/v2/prompts/{promptName}/version/{version}:
+    patch:
+      description: Update labels for a specific prompt version
+      operationId: promptVersion_update
+      tags:
+        - PromptVersion
+      parameters:
+        - name: promptName
+          in: path
+          description: The name of the prompt
+          required: true
+          schema:
+            type: string
+        - name: version
+          in: path
+          description: Version of the prompt to update
+          required: true
+          schema:
+            type: integer
+      responses:
+        '200':
+          description: ''
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Prompt'
+        '400':
+          description: ''
+          content:
+            application/json:
+              schema: {}
+        '401':
+          description: ''
+          content:
+            application/json:
+              schema: {}
+        '403':
+          description: ''
+          content:
+            application/json:
+              schema: {}
+        '404':
+          description: ''
+          content:
+            application/json:
+              schema: {}
+        '405':
+          description: ''
+          content:
+            application/json:
+              schema: {}
+      security:
+        - BasicAuth: []
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema:
+              type: object
+              properties:
+                newLabels:
+                  type: array
+                  items:
+                    type: string
+                  description: >-
+                    New labels for the prompt version. Labels are unique across
+                    versions. The "latest" label is reserved and managed by
+                    Langfuse.
+              required:
+                - newLabels
   /api/public/v2/prompts/{promptName}:
     get:
       description: Get a prompt
@@ -3183,11 +3256,12 @@ components:
             to exact match, use `(?i)^modelname$`
         startDate:
           type: string
-          format: date
+          format: date-time
           nullable: true
           description: Apply only to generations which are newer than this ISO date.
         unit:
           $ref: '#/components/schemas/ModelUsageUnit'
+          nullable: true
           description: Unit used by this model.
         inputPrice:
           type: number
@@ -3223,7 +3297,6 @@ components:
         - id
         - modelName
         - matchPattern
-        - unit
         - isLangfuseManaged
     ModelUsageUnit:
       title: ModelUsageUnit
@@ -4276,6 +4349,7 @@ components:
           description: Apply only to generations which are newer than this ISO date.
         unit:
           $ref: '#/components/schemas/ModelUsageUnit'
+          nullable: true
           description: Unit used by this model.
         inputPrice:
           type: number
@@ -4308,7 +4382,6 @@ components:
       required:
         - modelName
         - matchPattern
-        - unit
     Observations:
       title: Observations
       type: object
diff --git a/langfuse-core/src/index.ts b/langfuse-core/src/index.ts
index 53a7dea0..d1ddd6c0 100644
--- a/langfuse-core/src/index.ts
+++ b/langfuse-core/src/index.ts
@@ -56,6 +56,7 @@ import {
   type UpdateLangfuseGenerationBody,
   type UpdateLangfuseSpanBody,
   type GetMediaResponse,
+  UpdatePromptBody,
 } from "./types";
 import { LangfuseMedia, type LangfuseMediaResolveMediaReferencesParams } from "./media/LangfuseMedia";
 import {
@@ -527,6 +528,15 @@ abstract class LangfuseCoreStateless {
     );
   }
 
+  async updatePromptStateless(
+    body: UpdatePromptBody & { name: string; version: number }
+  ): Promise<LangfusePromptClient> {
+    return this.fetchAndLogErrors(
+      `${this.baseUrl}/api/public/v2/prompts/${encodeURIComponent(body.name)}/versions/${encodeURIComponent(body.version)}`,
+      this._getFetchOptions({ method: "PATCH", body: JSON.stringify(body) })
+    );
+  }
+
   async getPromptStateless(
     name: string,
     version?: number,
@@ -1382,6 +1392,12 @@ export abstract class LangfuseCore extends LangfuseCoreStateless {
     return new TextPromptClient(promptResponse);
   }
 
+  async updatePrompt(body: { name: string; version: number; newLabels: string[] }): Promise<LangfusePromptClient> {
+    const newPrompt = await this.updatePromptStateless(body);
+    this._promptCache.invalidate(body.name);
+    return newPrompt;
+  }
+
   async getPrompt(
     name: string,
     version?: number,
diff --git a/langfuse-core/src/openapi/server.ts b/langfuse-core/src/openapi/server.ts
index 2fbc6996..18a90926 100644
--- a/langfuse-core/src/openapi/server.ts
+++ b/langfuse-core/src/openapi/server.ts
@@ -190,6 +190,7 @@ export interface paths {
      *
      *     Notes:
      *
+     *     - Introduction to data model: https://langfuse.com/docs/tracing-data-model
      *     - Batch sizes are limited to 3.5 MB in total. You need to adjust the number of events per batch accordingly.
      *     - The API does not return a 4xx status code for input errors. Instead, it responds with a 207 status code, which includes a list of the encountered errors. */
     post: operations["ingestion_batch"];
@@ -338,6 +339,23 @@ export interface paths {
     patch?: never;
     trace?: never;
   };
+  "/api/public/v2/prompts/{promptName}/version/{version}": {
+    parameters: {
+      query?: never;
+      header?: never;
+      path?: never;
+      cookie?: never;
+    };
+    get?: never;
+    put?: never;
+    post?: never;
+    delete?: never;
+    options?: never;
+    head?: never;
+    /** @description Update labels for a specific prompt version */
+    patch: operations["promptVersion_update"];
+    trace?: never;
+  };
   "/api/public/v2/prompts/{promptName}": {
     parameters: {
       query?: never;
@@ -949,12 +967,12 @@ export interface components {
       /** @description Regex pattern which matches this model definition to generation.model. Useful in case of fine-tuned models. If you want to exact match, use `(?i)^modelname$` */
       matchPattern: string;
       /**
-       * Format: date
+       * Format: date-time
        * @description Apply only to generations which are newer than this ISO date.
        */
       startDate?: string | null;
       /** @description Unit used by this model. */
-      unit: components["schemas"]["ModelUsageUnit"];
+      unit?: components["schemas"]["ModelUsageUnit"];
       /**
        * Format: double
        * @description Price (USD) per input unit
@@ -1477,7 +1495,7 @@ export interface components {
        */
       startDate?: string | null;
       /** @description Unit used by this model. */
-      unit: components["schemas"]["ModelUsageUnit"];
+      unit?: components["schemas"]["ModelUsageUnit"];
       /**
        * Format: double
        * @description Price (USD) per input unit
@@ -3317,6 +3335,77 @@ export interface operations {
       };
     };
   };
+  promptVersion_update: {
+    parameters: {
+      query?: never;
+      header?: never;
+      path: {
+        /** @description The name of the prompt */
+        promptName: string;
+        /** @description Version of the prompt to update */
+        version: number;
+      };
+      cookie?: never;
+    };
+    requestBody: {
+      content: {
+        "application/json": {
+          /** @description New labels for the prompt version. Labels are unique across versions. The "latest" label is reserved and managed by Langfuse. */
+          newLabels: string[];
+        };
+      };
+    };
+    responses: {
+      200: {
+        headers: {
+          [name: string]: unknown;
+        };
+        content: {
+          "application/json": components["schemas"]["Prompt"];
+        };
+      };
+      400: {
+        headers: {
+          [name: string]: unknown;
+        };
+        content: {
+          "application/json": unknown;
+        };
+      };
+      401: {
+        headers: {
+          [name: string]: unknown;
+        };
+        content: {
+          "application/json": unknown;
+        };
+      };
+      403: {
+        headers: {
+          [name: string]: unknown;
+        };
+        content: {
+          "application/json": unknown;
+        };
+      };
+      404: {
+        headers: {
+          [name: string]: unknown;
+        };
+        content: {
+          "application/json": unknown;
+        };
+      };
+      405: {
+        headers: {
+          [name: string]: unknown;
+        };
+        content: {
+          "application/json": unknown;
+        };
+      };
+    };
+  };
   prompts_get: {
     parameters: {
       query?: {
diff --git a/langfuse-core/src/prompts/promptCache.ts b/langfuse-core/src/prompts/promptCache.ts
index 69cc2f37..729a40a7 100644
--- a/langfuse-core/src/prompts/promptCache.ts
+++ b/langfuse-core/src/prompts/promptCache.ts
@@ -50,4 +50,12 @@ export class LangfusePromptCache {
   public isRefreshing(key: string): boolean {
     return this._refreshingKeys.has(key);
   }
+
+  public invalidate(promptName: string): void {
+    for (const key of this._cache.keys()) {
+      if (key.startsWith(promptName)) {
+        this._cache.delete(key);
+      }
+    }
+  }
 }
diff --git a/langfuse-core/src/types.ts b/langfuse-core/src/types.ts
index 9545145e..a56b3e34 100644
--- a/langfuse-core/src/types.ts
+++ b/langfuse-core/src/types.ts
@@ -161,6 +161,9 @@ export type GetLangfuseDatasetRunsResponse = FixTypes<
 export type CreateLangfusePromptBody = FixTypes<
   paths["/api/public/v2/prompts"]["post"]["requestBody"]["content"]["application/json"]
 >;
+export type UpdatePromptBody = FixTypes<
+  paths["/api/public/v2/prompts/{promptName}/version/{version}"]["patch"]["requestBody"]["content"]["application/json"]
+>;
 export type CreateLangfusePromptResponse =
   paths["/api/public/v2/prompts"]["post"]["responses"]["200"]["content"]["application/json"];