AI Chat v2 API Integration Guide

The AI Chat v2 API (/aichat2/conversations) is the next-generation conversational interface, a comprehensive upgrade of the AI Chat API. Building on the simplicity and multi-turn conversation hosting of v1, it extends with:

Multimodal User Input: Directly pass text + images + file blocks via a structured message field without needing to attach them indirectly via references.
Agent-style Tool Invocation: Built-in tools for web search, web scraping, file reading, etc., with the ability to mount user-authorized MCP servers (Google Drive, Notion, Slack, GitHub, etc.). The model can autonomously invoke tools multiple times within a single request to complete complex tasks.
Structured Streaming Events: By setting accept: text/event-stream or application/x-ndjson, you can receive token-by-token events such as text_delta, tool_use, tool_result, thinking, citation, card, artifact, etc., facilitating frontend rendering by event type.
Interruptible / Resumable: When the model needs additional user input, it emits an ask_user_question event and pauses; the next call can resume by feeding back answers via tool_results.
New CRUD Actions: Supports retrieve / retrieve_batch / update / delete via the same endpoint using the action field, eliminating the need for separate session management APIs.
Continuously Updated Model List: Default access to contemporary models such as GPT-5.4, Claude Opus 4.7, Claude Sonnet 4.6, Gemini 3.1 Pro, GLM 5.1, DeepSeek V4, Kimi K2.5, and more.

It is also fully backward compatible with v1 at the request body level: simply pass model + question (+ optional stateful / id / references / preset) to get a {answer, id} JSON response equivalent to v1. Thus, migrating from /aichat/conversations only requires changing the path to /aichat2/conversations without rewriting the client.

If you are currently using /aichat/conversations, the old interface will remain available, so you can migrate at your own pace.

Application Process

To use the API, first apply for the corresponding service on the AI Chat v2 API page. After entering the page, click the “Acquire” button to obtain the credentials needed for requests. If you are not logged in or registered, you will be automatically redirected to the login page. After registering and logging in, you will be returned to the current page. A free quota is granted upon first application, allowing free usage of the API.

Basic Usage

The simplest usage is identical to v1: pass model + question and receive {answer, id}. CURL example:

curl -X POST 'https://api.xhuoapi.ai/v1/aichat2/conversations' \
  -H 'accept: application/json' \
  -H 'authorization: Bearer {token}' \
  -H 'content-type: application/json' \
  -d '{
    "model": "gpt-5.4",
    "question": "Introduce XHuoAPI in one sentence."
  }'

Response:

{
  "answer": "XHuoAPI is a unified API platform aggregating mainstream AI models and multimodal services, allowing developers to access GPT, Claude, Gemini, Midjourney, Suno, Veo, and others with a single key.",
  "id": "f2f4b3e8-0c0a-4d3a-aaa2-7ff80c0a1c44"
}

Python example:

import requests

url = "https://api.xhuoapi.ai/v1/aichat2/conversations"

headers = {
    "accept": "application/json",
    "authorization": "Bearer {token}",
    "content-type": "application/json",
}

payload = {
    "model": "gpt-5.4",
    "question": "Introduce XHuoAPI in one sentence.",
}

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

Available model values can be seen directly in the Try panel dropdown on the right. Common categories include:

OpenAI: gpt-5.4-mini, gpt-5.4-nano, gpt-5.2-pro, gpt-5.1-all, gpt-5-all, gpt-4.1, gpt-4o, gpt-4o-image, o3, o4-mini, etc.
Anthropic: claude-opus-4-7, claude-opus-4-6, claude-opus-4-5-20251101, claude-sonnet-4-6, claude-sonnet-4-5-20250929, claude-haiku-4-5-20251001, etc.
Google: gemini-3.1-pro, gemini-3.1-pro-preview, gemini-3.1-flash-image-preview, gemini-3-pro-preview, gemini-2.5-flash-lite, etc.
xAI: grok-4, grok-4-1-fast, grok-4-1-fast-reasoning, grok-3-mini-fast, etc.
DeepSeek: deepseek-v4-flash, deepseek-v3.2-exp, deepseek-r1-0528, etc.
Moonshot: kimi-k2.5, kimi-k2-thinking, kimi-k2-thinking-turbo, etc.
Zhipu: glm-5.1, glm-5, glm-5-turbo, glm-4.7, glm-4.5v, etc.

Refer to the Pricing card on the service page for detailed billing rules.

Multi-turn Conversations

As with v1, pass stateful: true to enable session saving. The API returns an id; subsequent requests include this id to continue the conversation without maintaining the message history yourself. First request:

curl -X POST 'https://api.xhuoapi.ai/v1/aichat2/conversations' \
  -H 'accept: application/json' \
  -H 'authorization: Bearer {token}' \
  -H 'content-type: application/json' \
  -d '{
    "model": "gpt-5.4",
    "stateful": true,
    "question": "Remember a number: 42."
  }'

Response:

{
  "answer": "Okay, I have remembered 42. What would you like me to do with it?",
  "id": "f2f4b3e8-0c0a-4d3a-aaa2-7ff80c0a1c44"
}

Second request, with the same id:

curl -X POST 'https://api.xhuoapi.ai/v1/aichat2/conversations' \
  -H 'accept: application/json' \
  -H 'authorization: Bearer {token}' \
  -H 'content-type: application/json' \
  -d '{
    "model": "gpt-5.4",
    "stateful": true,
    "id": "f2f4b3e8-0c0a-4d3a-aaa2-7ff80c0a1c44",
    "question": "What number did I ask you to remember?"
  }'

Response:

{
  "answer": "The number you asked me to remember is 42.",
  "id": "f2f4b3e8-0c0a-4d3a-aaa2-7ff80c0a1c44"
}

The default for stateful is true. Omitting it is equivalent to explicitly passing true. If you do not want the server to save this conversation, explicitly set stateful: false.

Streaming Responses

v2 supports two streaming formats, selectable via the accept header:

Scenario	`accept`	Data Format
Web frontend / EventSource	`text/event-stream`	`data: {json}\n\n`, ends with `data: [DONE]\n\n`
Server / CLI / Node streaming	`application/x-ndjson`	One JSON object per line
No streaming needed	`application/json` (default)	Single `{answer, id}` response

NDJSON Example

import json
import requests

url = "https://api.xhuoapi.ai/v1/aichat2/conversations"

headers = {
    "accept": "application/x-ndjson",
    "authorization": "Bearer {token}",
    "content-type": "application/json",
}

payload = {
    "model": "gpt-5.4",
    "stateful": True,
    "question": "Introduce Hangzhou in three sentences.",
}

with requests.post(url, json=payload, headers=headers, stream=True) as resp:
    answer = ""
    for line in resp.iter_lines():
        if not line:
            continue
        event = json.loads(line)
        if event.get("type") == "text_delta":
            # Compatible with v1: incremental fragments also provided via delta_answer field
            answer += event["content"]
            print(event["delta_answer"], end="", flush=True)
        elif event.get("type") == "done":
            print()
            print("usage =", event.get("usage"))

Each NDJSON line is a structured event, most commonly text_delta:

{"type":"text_delta","content":"杭","delta_answer":"杭","id":"f2f4b3e8-..."}
{"type":"text_delta","content":"州","delta_answer":"州","id":"f2f4b3e8-..."}
{"type":"text_delta","content":"是","delta_answer":"是","id":"f2f4b3e8-..."}
...
{"type":"done","conversation_id":"f2f4b3e8-...","usage":{"prompt_tokens":21,"completion_tokens":58,"total_tokens":79},"terminal_reason":"natural_stop"}

SSE Example

Since browser EventSource does not support custom request bodies, it is recommended to use fetch with manual splitting by \n\n:

const resp = await fetch("https://api.xhuoapi.ai/v1/aichat2/conversations", {
  method: "POST",
  headers: {
    accept: "text/event-stream",
    authorization: "Bearer {token}",
    "content-type": "application/json",
  },
  body: JSON.stringify({
    model: "gpt-5.4",
    stateful: true,
    question: "Introduce Hangzhou in three sentences.",
  }),
});

const reader = resp.body.getReader();
const decoder = new TextDecoder();
let buffer = "";
while (true) {
  const { value, done } = await reader.read();
  if (done) break;
  buffer += decoder.decode(value, { stream: true });
  const blocks = buffer.split("\n\n");
  buffer = blocks.pop() ?? "";
  for (const block of blocks) {
    const dataLine = block.split("\n").find((l) => l.startsWith("data: "));
    if (!dataLine) continue;
    const payload = dataLine.slice(6);
    if (payload === "[DONE]") return;
    const event = JSON.parse(payload);
    if (event.type === "text_delta") process.stdout.write(event.content);
  }
}

Streaming Event Types

`type`	Description
`text_delta`	Incremental text fragment of the assistant’s answer. `content` is the new content; for v1 compatibility, the event also includes `delta_answer` (equal to `content`) and `id`.
`thinking`	Model’s reasoning process (only appears if the selected model exposes reasoning).
`tool_use`	Model decides to invoke a tool; event carries `tool_id`, `tool_name`, and `input`.
`tool_result`	Result of tool execution, paired with the previous `tool_use` via `tool_id`; `is_error` indicates failure.
`card`	Structured card output from tools (e.g., images, link previews), suitable for direct rendering.
`citation`	Source URLs supplementing referenced text fragments.
`ask_user_question`	Model requests additional user input, conversation enters `awaiting_user_input` state; see Resuming Paused Conversations.
`artifact`	Independent artifacts generated by the model (e.g., code blocks, documents), can be saved or downloaded.
`system_message`	System prompt messages (not user or assistant content), for UI hints only.
`compact`	Internal context compression event, no special handling needed.
`error`	Error occurred in this turn; `message` describes the error.
`done`	Streaming response ended, includes `usage` (with `prompt_tokens` / `completion_tokens` / `total_tokens`) and `terminal_reason`.

Clients only interested in the final answer can concatenate all text_delta content fragments, which is equivalent to the answer in application/json mode.

Multimodal Input

If user input includes images or files, pass message (an array) instead of question. Each array element is a content block:

{
  "model": "gpt-5.4",
  "stateful": true,
  "message": [
    { "type": "text", "text": "How many cats are in this picture?" },
    { "type": "image_url", "image_url": { "url": "https://cdn.xhuoapi.ai/cats.jpg" } }
  ]
}

Supported block types:

text — plain text, requires text field.
image_url — image, requires image_url.url.
file_url — file (PDF, CSV, TXT, etc.), requires file_url.url.

Relation to v1 `references`

For backward compatibility, v2 still recognizes the references: ["https://...", ...] field:

URLs with suffixes jpg / jpeg / png / gif / bmp / webp / svg / heic / heif are automatically converted to image_url blocks;
Other extensions are converted to file_url blocks;
If question is also provided, it is prepended as a text block.

Therefore, if you want to migrate from v1 without changing the request body, just switch the path to /aichat2/conversations; the original references usage continues to work. For finer control (e.g., placing multiple images between texts or preserving order), use the message array directly.

Tool Invocation and MCP

A core enhancement in v2 is that the model can autonomously invoke tools to complete multi-step tasks. This is enabled by default and requires no extra client configuration. Common scenarios:

User asks, “Help me search for recent exhibitions in Shanghai” → model invokes built-in web search → organizes results into an answer.
User asks, “Read this PDF and write a summary” → model invokes file_read → writes summary.
User has authorized Google Drive / GitHub / Notion, etc. in Connections → model can invoke corresponding MCP tools to read/write data.

In NDJSON / SSE streams, tool invocation is represented by tool_use and tool_result events, for example:

{"type":"tool_use","tool_id":"toolu_01ABCDEF","tool_name":"web_search","input":{"query":"Shanghai 2026 spring exhibitions"},"id":"f2f4b3e8-..."}
{"type":"tool_result","tool_id":"toolu_01ABCDEF","output":"...","is_error":false,"id":"f2f4b3e8-..."}
{"type":"text_delta","content":"Currently","delta_answer":"Currently","id":"f2f4b3e8-..."}
{"type":"text_delta","content":"Shanghai","delta_answer":"Shanghai","id":"f2f4b3e8-..."}
...

If you do not want to display tool invocation details on the frontend, simply ignore tool_use / tool_result / card / citation events; the model’s final output still flows through text_delta. The max_turns parameter limits how many times the model can self-invoke tools in this request. The default upper limit is platform-determined. Setting it low (e.g., max_turns: 1) forces a single answer without any tool invocation.

Resuming Paused Conversations

Some tools cause the model to “ask the user” for clarification. The model emits an ask_user_question event, and the conversation freezes in the awaiting_user_input state:

{
  "type": "ask_user_question",
  "tool_id": "toolu_01XYZW",
  "tool_name": "ask_user_question",
  "question": "Do you want the report in Chinese or English?",
  "options": ["Chinese", "English"],
  "id": "f2f4b3e8-..."
}

Render this event as a card on the frontend to let the user select an answer, then initiate the next request with the same id, feeding back the answer via tool_results:

curl -X POST 'https://api.xhuoapi.ai/v1/aichat2/conversations' \
  -H 'accept: text/event-stream' \
  -H 'authorization: Bearer {token}' \
  -H 'content-type: application/json' \
  -d '{
    "model": "gpt-5.4",
    "stateful": true,
    "id": "f2f4b3e8-0c0a-4d3a-aaa2-7ff80c0a1c44",
    "tool_results": [
      {
        "tool_use_id": "toolu_01XYZW",
        "output": "Chinese"
      }
    ]
  }'

The tool_use_id in the request must exactly match the paused tool_id; mismatches will return 400. When tool_results is present, question / message / references are ignored. If the user decides to skip the question, simply send a new question or message; the platform will automatically mark the paused tool invocation as “user skipped.”

Conversation Management (CRUD)

v2 provides lightweight conversation management via the same endpoint using the action field, no separate API needed.

`action: retrieve` — Fetch a conversation

curl -X POST 'https://api.xhuoapi.ai/v1/aichat2/conversations' \
  -H 'accept: application/json' \
  -H 'authorization: Bearer {token}' \
  -H 'content-type: application/json' \
  -d '{
    "action": "retrieve",
    "id": "f2f4b3e8-0c0a-4d3a-aaa2-7ff80c0a1c44"
  }'

Returns the full conversation document (including messages history, model, title, tools_used, etc.).

`action: retrieve_batch` — List conversation summaries

{
  "action": "retrieve_batch",
  "model_group": "chatgpt",
  "limit": 20,
  "offset": 0
}

Returns { items: [...], total }. Summaries do not include messages, suitable for sidebar lists. When the user opens a conversation, use action: retrieve to fetch full messages. Optional filters: user_id, application_id, model_group, model.

`action: update` — Change title or rewrite history

{
  "action": "update",
  "id": "f2f4b3e8-0c0a-4d3a-aaa2-7ff80c0a1c44",
  "title": "Hangzhou Travel Plan"
}

messages can also be passed but the server performs strict schema validation (must be folded ToolUseContent form); invalid data returns 400. Generally, only title changes are recommended.

`action: delete` — Delete a conversation

{
  "action": "delete",
  "id": "f2f4b3e8-0c0a-4d3a-aaa2-7ff80c0a1c44"
}

Returns { id, success: true }. Deletion is irreversible; confirm before calling.

Smooth Migration from v1

If you are already using /aichat/conversations, migrating to v2 requires almost no code changes:

Change the URL from https://api.xhuoapi.ai/v1/aichat/conversations to https://api.xhuoapi.ai/v1/aichat2/conversations.
If you previously used v1 model names (e.g., gpt-3.5, gpt-4-browsing), it is recommended to upgrade to contemporary models (e.g., gpt-5.4, claude-opus-4-7, gemini-3.1-pro) when switching to v2.
NDJSON stream fields remain backward compatible: each text_delta event still carries delta_answer and id, so clients parsing delta_answer line-by-line need no changes.

After migration, you can gradually enable v2 features (multimodal message, SSE, tool invocation, action CRUD) at your own pace.

Error Handling

Error responses have a unified format:

{
  "error": {
    "code": "chat_error",
    "message": "upstream LLM returned an error"
  },
  "trace_id": "2cf86e86-22a4-46e1-ac2f-032c0f2a4e89"
}

Common errors:

400 bad_request: missing required fields, tool_use_id mismatch, invalid messages schema, etc.
401 invalid_token: incorrect authorization header.
404 not_found: conversation with specified id does not exist for action: retrieve / update / delete.
429 too_many_requests: rate limit exceeded.
500 chat_error: upstream LLM error or completion_tokens=0 for the turn (treated as no consumption, no charge).

In streaming responses, errors are emitted as {"type":"error","message":"..."} events, followed immediately by stream termination.

Conclusion

The AI Chat v2 API is backward compatible with v1 while upgrading conversations from “single-turn / multi-turn Q&A” to “agent-style observable dialogues”: multimodal input, tool invocation, pausable/resumable sessions, structured streaming events, and built-in CRUD. It is recommended to use v2 for new integrations; existing v1 integrations can migrate smoothly in phases. For any questions, please contact our technical support team at any time.

Documentation Index

​Application Process

​Basic Usage

​Multi-turn Conversations

​Streaming Responses

​NDJSON Example

​SSE Example

​Streaming Event Types

​Multimodal Input

​Relation to v1 references

​Tool Invocation and MCP

​Resuming Paused Conversations

​Conversation Management (CRUD)

​action: retrieve — Fetch a conversation

​action: retrieve_batch — List conversation summaries

​action: update — Change title or rewrite history

​action: delete — Delete a conversation

​Smooth Migration from v1

​Error Handling

​Conclusion

Application Process

Basic Usage

Multi-turn Conversations

Streaming Responses

NDJSON Example

SSE Example

Streaming Event Types

Multimodal Input

Relation to v1 `references`

Tool Invocation and MCP

Resuming Paused Conversations

Conversation Management (CRUD)

`action: retrieve` — Fetch a conversation

`action: retrieve_batch` — List conversation summaries

`action: update` — Change title or rewrite history

`action: delete` — Delete a conversation

Smooth Migration from v1

Error Handling

Conclusion