{ "info": { "_postman_id": "4720fa5d-56ab-464d-bfa8-3197cc5049fb", "name": "Amplitude Experiment Evaluation API", "description": "The Amplitude Experiment Evaluation API retrieves variant assignment data for users through remote evaluation. When called, it evaluates targeting rules and returns the assigned variant for each active experiment or feature flag. The API also tracks assignment events automatically in Amplitude Analytics. It is used by server-side applications that need to determine which experiment variant or feature flag value to serve to a given user in real time.\n\nContact Support:\n Name: Amplitude Support", "schema": "https://schema.getpostman.com/json/collection/v2.1.0/collection.json", "createdAt": "2026-06-05T15:05:38.000Z", "updatedAt": "2026-06-05T15:05:39.000Z", "lastUpdatedBy": "35240", "uid": "35240-4720fa5d-56ab-464d-bfa8-3197cc5049fb" }, "item": [ { "name": "v1", "item": [ { "name": "vardata", "item": [ { "name": "Amplitude Evaluate Variants for a User", "id": "fd9ca760-4865-420b-a3a7-714bebd4b802", "protocolProfileBehavior": { "disableBodyPruning": true }, "request": { "method": "POST", "header": [ { "key": "Content-Type", "value": "application/json" }, { "key": "Accept", "value": "application/json" } ], "body": { "mode": "raw", "raw": "{\n \"user_id\": \"\",\n \"device_id\": \"\",\n \"user_properties\": {\n \"eiusmodcd\": 93028036,\n \"sedc\": 47044522.66226852\n },\n \"groups\": {\n \"fugiat74a\": -95293110.77119096,\n \"eac\": false\n },\n \"group_properties\": {\n \"ullamco_9c8\": true\n }\n}", "options": { "raw": { "headerFamily": "json", "language": "json" } } }, "url": { "raw": "{{baseUrl}}/v1/vardata", "host": [ "{{baseUrl}}" ], "path": [ "v1", "vardata" ] }, "description": "Remotely evaluate all active experiments and feature flags for a specific user. Returns the variant assignments based on the user's properties and targeting rules. Amplitude automatically tracks an Experiment Assignment event for each evaluation." }, "response": [ { "id": "6a1ea8b5-4814-4bc1-ba08-9ef70c5bcdd0", "name": "Success", "originalRequest": { "method": "POST", "header": [ { "key": "Content-Type", "value": "application/json" }, { "key": "Accept", "value": "application/json" }, { "description": "Added as a part of security scheme: apikey", "key": "Authorization", "value": "" } ], "body": { "mode": "raw", "raw": "{\n \"user_id\": \"\",\n \"device_id\": \"\",\n \"user_properties\": {\n \"eiusmodcd\": 93028036,\n \"sedc\": 47044522.66226852\n },\n \"groups\": {\n \"fugiat74a\": -95293110.77119096,\n \"eac\": false\n },\n \"group_properties\": {\n \"ullamco_9c8\": true\n }\n}", "options": { "raw": { "headerFamily": "json", "language": "json" } } }, "url": { "raw": "{{baseUrl}}/v1/vardata", "host": [ "{{baseUrl}}" ], "path": [ "v1", "vardata" ] } }, "status": "OK", "code": 200, "_postman_previewlanguage": "json", "header": [ { "key": "Content-Type", "value": "application/json" } ], "cookie": [], "responseTime": null, "body": "{\n \"consequat8\": {\n \"key\": \"\",\n \"value\": \"\",\n \"payload\": {\n \"description\": \"An optional JSON payload associated with the variant.\"\n },\n \"metadata\": {\n \"experimentKey\": \"\",\n \"flagType\": \"\",\n \"flagVersion\": \"\",\n \"default\": \"\"\n }\n },\n \"Excepteur6f\": {\n \"key\": \"\",\n \"value\": \"\",\n \"payload\": {\n \"description\": \"An optional JSON payload associated with the variant.\"\n },\n \"metadata\": {\n \"experimentKey\": \"\",\n \"flagType\": \"\",\n \"flagVersion\": \"\",\n \"default\": \"\"\n }\n },\n \"consectetur_9\": {\n \"key\": \"\",\n \"value\": \"\",\n \"payload\": {\n \"description\": \"An optional JSON payload associated with the variant.\"\n },\n \"metadata\": {\n \"experimentKey\": \"\",\n \"flagType\": \"\",\n \"flagVersion\": \"\",\n \"default\": \"\"\n }\n }\n}", "createdAt": "2026-06-05T15:05:39.000Z", "updatedAt": "2026-06-05T15:05:39.000Z", "uid": "35240-6a1ea8b5-4814-4bc1-ba08-9ef70c5bcdd0" }, { "id": "9dd2ab38-5ee3-4e5b-9708-68f3b5fb6794", "name": "Bad request - missing user context", "originalRequest": { "method": "POST", "header": [ { "key": "Content-Type", "value": "application/json" }, { "description": "Added as a part of security scheme: apikey", "key": "Authorization", "value": "" } ], "body": { "mode": "raw", "raw": "{\n \"user_id\": \"\",\n \"device_id\": \"\",\n \"user_properties\": {\n \"eiusmodcd\": 93028036,\n \"sedc\": 47044522.66226852\n },\n \"groups\": {\n \"fugiat74a\": -95293110.77119096,\n \"eac\": false\n },\n \"group_properties\": {\n \"ullamco_9c8\": true\n }\n}", "options": { "raw": { "headerFamily": "json", "language": "json" } } }, "url": { "raw": "{{baseUrl}}/v1/vardata", "host": [ "{{baseUrl}}" ], "path": [ "v1", "vardata" ] } }, "status": "Bad Request", "code": 400, "_postman_previewlanguage": "text", "header": [], "cookie": [], "responseTime": null, "body": null, "createdAt": "2026-06-05T15:05:39.000Z", "updatedAt": "2026-06-05T15:05:39.000Z", "uid": "35240-9dd2ab38-5ee3-4e5b-9708-68f3b5fb6794" }, { "id": "661536d2-f9ec-4197-be3d-66b097321779", "name": "Unauthorized - invalid deployment key", "originalRequest": { "method": "POST", "header": [ { "key": "Content-Type", "value": "application/json" }, { "description": "Added as a part of security scheme: apikey", "key": "Authorization", "value": "" } ], "body": { "mode": "raw", "raw": "{\n \"user_id\": \"\",\n \"device_id\": \"\",\n \"user_properties\": {\n \"eiusmodcd\": 93028036,\n \"sedc\": 47044522.66226852\n },\n \"groups\": {\n \"fugiat74a\": -95293110.77119096,\n \"eac\": false\n },\n \"group_properties\": {\n \"ullamco_9c8\": true\n }\n}", "options": { "raw": { "headerFamily": "json", "language": "json" } } }, "url": { "raw": "{{baseUrl}}/v1/vardata", "host": [ "{{baseUrl}}" ], "path": [ "v1", "vardata" ] } }, "status": "Unauthorized", "code": 401, "_postman_previewlanguage": "text", "header": [], "cookie": [], "responseTime": null, "body": null, "createdAt": "2026-06-05T15:05:39.000Z", "updatedAt": "2026-06-05T15:05:39.000Z", "uid": "35240-661536d2-f9ec-4197-be3d-66b097321779" } ], "createdAt": "2026-06-05T15:05:39.000Z", "updatedAt": "2026-06-05T15:05:39.000Z", "uid": "35240-fd9ca760-4865-420b-a3a7-714bebd4b802" }, { "name": "Amplitude Evaluate Variants for a User via GET", "id": "af1b2b9c-6f1e-4345-9e91-216e91db4782", "protocolProfileBehavior": { "disableBodyPruning": true }, "request": { "method": "GET", "header": [ { "key": "Accept", "value": "application/json" } ], "url": { "raw": "{{baseUrl}}/v1/vardata?user_id=&device_id=", "host": [ "{{baseUrl}}" ], "path": [ "v1", "vardata" ], "query": [ { "description": "The user ID to evaluate variants for.", "key": "user_id", "value": "" }, { "description": "The device ID to evaluate variants for.", "key": "device_id", "value": "" } ] }, "description": "Remotely evaluate all active experiments and feature flags for a user identified by query parameters. Returns variant assignments based on targeting rules." }, "response": [ { "id": "70e8e8cd-bcb9-4eb9-804f-edbace0c8e67", "name": "Success", "originalRequest": { "method": "GET", "header": [ { "key": "Accept", "value": "application/json" }, { "description": "Added as a part of security scheme: apikey", "key": "Authorization", "value": "" } ], "url": { "raw": "{{baseUrl}}/v1/vardata?user_id=&device_id=", "host": [ "{{baseUrl}}" ], "path": [ "v1", "vardata" ], "query": [ { "description": "The user ID to evaluate variants for.", "key": "user_id", "value": "" }, { "description": "The device ID to evaluate variants for.", "key": "device_id", "value": "" } ] } }, "status": "OK", "code": 200, "_postman_previewlanguage": "json", "header": [ { "key": "Content-Type", "value": "application/json" } ], "cookie": [], "responseTime": null, "body": "{\n \"consequat8\": {\n \"key\": \"\",\n \"value\": \"\",\n \"payload\": {\n \"description\": \"An optional JSON payload associated with the variant.\"\n },\n \"metadata\": {\n \"experimentKey\": \"\",\n \"flagType\": \"\",\n \"flagVersion\": \"\",\n \"default\": \"\"\n }\n },\n \"Excepteur6f\": {\n \"key\": \"\",\n \"value\": \"\",\n \"payload\": {\n \"description\": \"An optional JSON payload associated with the variant.\"\n },\n \"metadata\": {\n \"experimentKey\": \"\",\n \"flagType\": \"\",\n \"flagVersion\": \"\",\n \"default\": \"\"\n }\n },\n \"consectetur_9\": {\n \"key\": \"\",\n \"value\": \"\",\n \"payload\": {\n \"description\": \"An optional JSON payload associated with the variant.\"\n },\n \"metadata\": {\n \"experimentKey\": \"\",\n \"flagType\": \"\",\n \"flagVersion\": \"\",\n \"default\": \"\"\n }\n }\n}", "createdAt": "2026-06-05T15:05:39.000Z", "updatedAt": "2026-06-05T15:05:39.000Z", "uid": "35240-70e8e8cd-bcb9-4eb9-804f-edbace0c8e67" }, { "id": "974e33f1-6e04-457d-a539-cb99d181d159", "name": "Unauthorized", "originalRequest": { "method": "GET", "header": [ { "description": "Added as a part of security scheme: apikey", "key": "Authorization", "value": "" } ], "url": { "raw": "{{baseUrl}}/v1/vardata?user_id=&device_id=", "host": [ "{{baseUrl}}" ], "path": [ "v1", "vardata" ], "query": [ { "description": "The user ID to evaluate variants for.", "key": "user_id", "value": "" }, { "description": "The device ID to evaluate variants for.", "key": "device_id", "value": "" } ] } }, "status": "Unauthorized", "code": 401, "_postman_previewlanguage": "text", "header": [], "cookie": [], "responseTime": null, "body": null, "createdAt": "2026-06-05T15:05:39.000Z", "updatedAt": "2026-06-05T15:05:39.000Z", "uid": "35240-974e33f1-6e04-457d-a539-cb99d181d159" } ], "createdAt": "2026-06-05T15:05:39.000Z", "updatedAt": "2026-06-05T15:05:39.000Z", "uid": "35240-af1b2b9c-6f1e-4345-9e91-216e91db4782" } ], "id": "ab49fb43-56f3-4ed0-b968-f3434f299cab", "createdAt": "2026-06-05T15:05:39.000Z", "updatedAt": "2026-06-05T15:05:39.000Z", "uid": "35240-ab49fb43-56f3-4ed0-b968-f3434f299cab" }, { "name": "flags", "item": [ { "name": "Amplitude Get Flag Configurations", "id": "6b7a9398-c95d-4c74-9c03-eda164ba3407", "protocolProfileBehavior": { "disableBodyPruning": true }, "request": { "method": "GET", "header": [ { "key": "Accept", "value": "application/json" } ], "url": { "raw": "{{baseUrl}}/v1/flags", "host": [ "{{baseUrl}}" ], "path": [ "v1", "flags" ] }, "description": "Download all flag configurations for local evaluation. This endpoint returns the full flag configuration including targeting rules, variants, and segment definitions. Useful for bootstrapping client-side local evaluation SDKs with initialFlags or running evaluation in edge environments." }, "response": [ { "id": "1b212816-11c3-40c7-b88f-b599d3ee3ce1", "name": "Success", "originalRequest": { "method": "GET", "header": [ { "key": "Accept", "value": "application/json" }, { "description": "Added as a part of security scheme: apikey", "key": "Authorization", "value": "" } ], "url": { "raw": "{{baseUrl}}/v1/flags", "host": [ "{{baseUrl}}" ], "path": [ "v1", "flags" ] } }, "status": "OK", "code": 200, "_postman_previewlanguage": "json", "header": [ { "key": "Content-Type", "value": "application/json" } ], "cookie": [], "responseTime": null, "body": "[\n {\n \"key\": \"\",\n \"metadata\": {\n \"deployed\": \"\",\n \"evaluationMode\": \"\",\n \"flagType\": \"\",\n \"flagVersion\": \"\"\n },\n \"segments\": [\n {\n \"conditions\": [\n {\n \"esse9\": true,\n \"Lorem_d\": true\n },\n {\n \"id7f5\": \"enim anim qui\",\n \"Utb78\": true\n }\n ],\n \"variant\": \"\"\n },\n {\n \"conditions\": [\n {\n \"eiusmodf\": \"esse deserunt\"\n },\n {\n \"ipsum872\": 83999667.8288064\n }\n ],\n \"variant\": \"\"\n }\n ],\n \"variants\": {\n \"occaecat_8\": {\n \"key\": \"\",\n \"payload\": {\n \"description\": \"Optional payload for the variant.\"\n }\n }\n }\n },\n {\n \"key\": \"\",\n \"metadata\": {\n \"deployed\": \"\",\n \"evaluationMode\": \"\",\n \"flagType\": \"\",\n \"flagVersion\": \"\"\n },\n \"segments\": [\n {\n \"conditions\": [\n {\n \"quisbed\": \"enim irure\",\n \"ex_c17\": \"ullamco in\",\n \"officiad0\": true,\n \"in_d1\": -8849098.094844043\n },\n {\n \"eu50\": false\n }\n ],\n \"variant\": \"\"\n },\n {\n \"conditions\": [\n {\n \"reprehenderit571\": \"esse quis ut\",\n \"ea_a\": \"sit nulla\"\n },\n {\n \"in_c_8\": true,\n \"et9a\": false\n }\n ],\n \"variant\": \"\"\n }\n ],\n \"variants\": {\n \"Utce9\": {\n \"key\": \"\",\n \"payload\": {\n \"description\": \"Optional payload for the variant.\"\n }\n }\n }\n }\n]", "createdAt": "2026-06-05T15:05:39.000Z", "updatedAt": "2026-06-05T15:05:39.000Z", "uid": "35240-1b212816-11c3-40c7-b88f-b599d3ee3ce1" }, { "id": "94a114d9-1f05-4ae9-b9e1-6752b3e3518f", "name": "Unauthorized - invalid deployment key", "originalRequest": { "method": "GET", "header": [ { "description": "Added as a part of security scheme: apikey", "key": "Authorization", "value": "" } ], "url": { "raw": "{{baseUrl}}/v1/flags", "host": [ "{{baseUrl}}" ], "path": [ "v1", "flags" ] } }, "status": "Unauthorized", "code": 401, "_postman_previewlanguage": "text", "header": [], "cookie": [], "responseTime": null, "body": null, "createdAt": "2026-06-05T15:05:39.000Z", "updatedAt": "2026-06-05T15:05:39.000Z", "uid": "35240-94a114d9-1f05-4ae9-b9e1-6752b3e3518f" } ], "createdAt": "2026-06-05T15:05:39.000Z", "updatedAt": "2026-06-05T15:05:39.000Z", "uid": "35240-6b7a9398-c95d-4c74-9c03-eda164ba3407" } ], "id": "db9a6d28-9d6c-49e7-96c6-4a2ad71aedfb", "createdAt": "2026-06-05T15:05:39.000Z", "updatedAt": "2026-06-05T15:05:39.000Z", "uid": "35240-db9a6d28-9d6c-49e7-96c6-4a2ad71aedfb" } ], "id": "5cbbb45b-2e9d-4fdf-bffb-33ab3963f8c2", "createdAt": "2026-06-05T15:05:39.000Z", "updatedAt": "2026-06-05T15:05:39.000Z", "uid": "35240-5cbbb45b-2e9d-4fdf-bffb-33ab3963f8c2" } ], "auth": { "type": "apikey", "apikey": [ { "key": "key", "value": "Authorization", "type": "string" }, { "key": "value", "value": "{{apiKey}}", "type": "string" }, { "key": "in", "value": "header", "type": "string" } ] }, "variable": [ { "key": "baseUrl", "value": "https://api.lab.amplitude.com" } ] }