SSE Response Format

This document describes the Server-Sent Events (SSE) response format from the Bitseek Chat HTTP API.

Response Structure

Each SSE event contains a data: field with a JSON object following the OpenAI Chat Completions API format.

Event Format

data: {"id":"stream:chat:xxx","object":"chat.completion","created":1773042793,"model":"","choices":[{"index":0,"delta":{"content":"..."},"finish_reason":null}]}

Response Fields

Field	Type	Description
`id`	string	Stream identifier (format: `stream:chat:<uuid>`)
`object`	string	Always `"chat.completion"`
`created`	number	Unix timestamp of the response creation
`model`	string	Model identifier (may be empty string)
`choices`	array	Array of completion choices

Choices Array

Each choice object contains:

Field	Type	Description
`index`	number	Index of the choice (usually 0 for single response)
`delta`	object	The content delta/increment
`delta.content`	string	The incremental text content
`finish_reason`	string\	null	Reason for completion (`null` while streaming, `"stop"` when done)

Stream Completion

When finish_reason is "stop", the stream has completed.

Example Response Flow

First chunk:

data: {"id":"stream:chat:26e9476e-14e9-4165-915a-723ccbbaa5ad","object":"chat.completion","created":1773042793,"model":"","choices":[{"index":0,"delta":{"content":"Hello"},"finish_reason":null}]}

Middle chunk:

data: {"id":"stream:chat:26e9476e-14e9-4165-915a-723ccbbaa5ad","object":"chat.completion","created":1773042793,"model":"","choices":[{"index":0,"delta":{"content":"! How"},"finish_reason":null}]}

Final chunk (with finish_reason: "stop"):

data: {"id":"stream:chat:c51514fb-eaec-4f38-9bd9-6497993161c7","object":"chat.completion","created":1773044133,"model":"","choices":[{"index":0,"delta":{"content":""},"finish_reason":"stop"}]}

Parsing SSE Data

When parsing SSE responses:

Split by lines starting with data:
Extract the JSON after data:
Check for finish_reason === "stop" to detect completion
Concatenate all delta.content values to get the complete response

Example Parser (JavaScript)

const eventSource = new EventSource('https://chat-proxy.bitseek.ai/v1/chat/completions');
let fullContent = '';

eventSource.onmessage = (event) => {
  const data = JSON.parse(event.data);
  const choice = data.choices[0];

  // Check if stream is complete
  if (choice.finish_reason === 'stop') {
    console.log('Response complete:', fullContent);
    eventSource.close();
    return;
  }

  const content = choice.delta?.content || '';
  fullContent += content;
  process.stdout.write(content); // Stream to console
};

Response Format