Send Message

POST

chat

sessions

{sessionId}

messages

Send message

curl --request POST \
  --url https://api.agntix.ai/v1/chat/chat/sessions/{sessionId}/messages \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <api-key>' \
  --data '
{
  "content": "What is my current subscription plan?",
  "stream": true
}
'

const options = {
  method: 'POST',
  headers: {'x-api-key': '<api-key>', 'Content-Type': 'application/json'},
  body: JSON.stringify({content: 'What is my current subscription plan?', stream: true})
};

fetch('https://api.agntix.ai/v1/chat/chat/sessions/{sessionId}/messages', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

import requests

url = "https://api.agntix.ai/v1/chat/chat/sessions/{sessionId}/messages"

payload = {
    "content": "What is my current subscription plan?",
    "stream": True
}
headers = {
    "x-api-key": "<api-key>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

"<string>"

{
  "error": {
    "code": "VALIDATION_ERROR",
    "message": "fullName should not be empty",
    "status": 400
  },
  "meta": {
    "requestId": "req_01j3m...",
    "timestamp": "2026-04-29T10:00:00Z"
  }
}

{
  "error": {
    "code": "UNAUTHORIZED",
    "message": "Authentication required.",
    "status": 401
  },
  "meta": {
    "requestId": "req_01j3m...",
    "timestamp": "2026-04-29T10:00:00Z"
  }
}

{
  "error": {
    "code": "NOT_FOUND",
    "message": "Agent not found.",
    "status": 404
  },
  "meta": {
    "requestId": "req_01j3m...",
    "timestamp": "2026-04-29T10:00:00Z"
  }
}

Every endpoint on this page requires either a Clerk-issued JWT (Authorization: Bearer <token>) or an organization API key (x-api-key: pk_…). Anonymous calls return 401 Unauthorized. See Authentication for the full setup.

Streaming vs. non-streaming

By default ("stream": true), the agent’s reply is delivered as a Server-Sent Events stream. Set "stream": false to receive a single JSON response when you don’t need incremental rendering.

Code examples

curl -X POST https://api.agntix.ai/v1/chat/chat/sessions/ses_01j3m8xkqp8v2nw4f7g9hk0r/messages \
  -H "x-api-key: pk_live_••••" \
  -H "Content-Type: application/json" \
  --no-buffer \
  -d '{ "content": "What is my current subscription plan?", "stream": true }'

curl -X POST https://api.agntix.ai/v1/chat/chat/sessions/ses_01j3m8xkqp8v2nw4f7g9hk0r/messages \
  -H "x-api-key: pk_live_••••" \
  -H "Content-Type: application/json" \
  -d '{ "content": "What is my current subscription plan?", "stream": false }'

const sessionId = 'ses_01j3m8xkqp8v2nw4f7g9hk0r';

const res = await fetch(
  `https://api.agntix.ai/v1/chat/chat/sessions/${sessionId}/messages`,
  {
    method: 'POST',
    headers: {
      'x-api-key': 'pk_live_••••',
      'Content-Type': 'application/json',
    },
    body: JSON.stringify({
      content: 'What is my current subscription plan?',
      stream: true,
    }),
  },
);

const reader = res.body.getReader();
const decoder = new TextDecoder();
let fullReply = '';

while (true) {
  const { done, value } = await reader.read();
  if (done) break;

  const chunk = decoder.decode(value);
  for (const line of chunk.split('\n')) {
    if (line.startsWith('data: ') && line !== 'data: [DONE]') {
      const event = JSON.parse(line.slice(6));
      fullReply += event.delta ?? '';
      process.stdout.write(event.delta ?? '');
    }
  }
}
console.log('\nFull reply:', fullReply);

const message = await fetch(
  `https://api.agntix.ai/v1/chat/chat/sessions/${sessionId}/messages`,
  {
    method: 'POST',
    headers: {
      'x-api-key': 'pk_live_••••',
      'Content-Type': 'application/json',
    },
    body: JSON.stringify({ content: 'What is my plan?', stream: false }),
  },
).then(r => r.json());

console.log('Reply:', message.content);

import httpx

session_id = "ses_01j3m8xkqp8v2nw4f7g9hk0r"

with httpx.stream(
    "POST",
    f"https://api.agntix.ai/v1/chat/chat/sessions/{session_id}/messages",
    headers={"x-api-key": "pk_live_••••"},
    json={"content": "What is my current subscription plan?", "stream": True},
) as r:
    for line in r.iter_lines():
        if line.startswith("data: ") and line != "data: [DONE]":
            import json
            event = json.loads(line[6:])
            print(event.get("delta", ""), end="", flush=True)

import httpx

session_id = "ses_01j3m8xkqp8v2nw4f7g9hk0r"

message = httpx.post(
    f"https://api.agntix.ai/v1/chat/chat/sessions/{session_id}/messages",
    headers={"x-api-key": "pk_live_••••"},
    json={"content": "What is my current subscription plan?", "stream": False},
).json()

print("Reply:", message["content"])

SSE stream format

When stream: true, the response is Content-Type: text/event-stream. Each event:

data: {"id":"msg_01j3m","delta":"Your "}

data: {"id":"msg_01j3m","delta":"plan is Pro."}

data: [DONE]

The stream ends with the literal data: [DONE] sentinel.

Non-streaming response

{
  "id": "msg_01j3m...",
  "content": "Your current plan is Pro.",
  "role": "ASSISTANT",
  "createdAt": "2026-04-29T09:10:00Z"
}

Authorizations

x-api-key

string

header

required

Organization API key. Obtain from the dashboard. Format: pk_live_…

Path Parameters

sessionId

string

required

Body

application/json

content

string

required

The user's message.

Example:

"What is my current subscription plan?"

stream

boolean

default:true

Stream the response over SSE. Set false for a single JSON response.

Response

Assistant reply (SSE stream when stream: true, JSON object when stream: false).

The response is of type string.

Send message

curl --request POST \
  --url https://api.agntix.ai/v1/chat/chat/sessions/{sessionId}/messages \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <api-key>' \
  --data '
{
  "content": "What is my current subscription plan?",
  "stream": true
}
'

const options = {
  method: 'POST',
  headers: {'x-api-key': '<api-key>', 'Content-Type': 'application/json'},
  body: JSON.stringify({content: 'What is my current subscription plan?', stream: true})
};

fetch('https://api.agntix.ai/v1/chat/chat/sessions/{sessionId}/messages', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

import requests

url = "https://api.agntix.ai/v1/chat/chat/sessions/{sessionId}/messages"

payload = {
    "content": "What is my current subscription plan?",
    "stream": True
}
headers = {
    "x-api-key": "<api-key>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

"<string>"

{
  "error": {
    "code": "VALIDATION_ERROR",
    "message": "fullName should not be empty",
    "status": 400
  },
  "meta": {
    "requestId": "req_01j3m...",
    "timestamp": "2026-04-29T10:00:00Z"
  }
}

{
  "error": {
    "code": "UNAUTHORIZED",
    "message": "Authentication required.",
    "status": 401
  },
  "meta": {
    "requestId": "req_01j3m...",
    "timestamp": "2026-04-29T10:00:00Z"
  }
}

{
  "error": {
    "code": "NOT_FOUND",
    "message": "Agent not found.",
    "status": 404
  },
  "meta": {
    "requestId": "req_01j3m...",
    "timestamp": "2026-04-29T10:00:00Z"
  }
}

Overview

Agents

Chat

Voice

Tools

Phone Numbers

Streaming vs. non-streaming

Code examples

SSE stream format

Non-streaming response

Authorizations

Path Parameters

Body

Response

​Streaming vs. non-streaming

​Code examples

​SSE stream format

​Non-streaming response

Authorizations

Path Parameters

Body

Response

Streaming vs. non-streaming

Code examples

SSE stream format

Non-streaming response