API Reference

API Reference for LangDB

Create chat completion

post

Authorizations

Header parameters

X-Project-IdstringRequired

LangDB project ID

Body

modelstringRequired

ID of the model to use. This can be either a specific model ID or a virtual model identifier.

Example: gpt-4o

temperaturenumber · max: 2Optional

Sampling temperature.

Example: 0.8

Responses

200

application/json

post

POST /v1/chat/completions HTTP/1.1
Host: api.us-east-1.langdb.ai
Authorization: Bearer YOUR_SECRET_TOKEN
X-Project-Id: text
Content-Type: application/json
Accept: */*
Content-Length: 599

{
  "model": "gpt-4o",
  "messages": [
    {
      "role": "user",
      "content": "Write a haiku about recursion in programming."
    }
  ],
  "temperature": 0.8,
  "max_tokens": 1000,
  "top_p": 0.9,
  "frequency_penalty": 0.1,
  "presence_penalty": 0.2,
  "stream": false,
  "response_format": "json_object",
  "mcp_servers": [
    {
      "name": "websearch",
      "type": "in-memory"
    }
  ],
  "router": {
    "name": "kg_random_router",
    "type": "script",
    "script": "const route = ({ request, headers, models, metrics }) => { return {model: 'test'};};"
  },
  "extra": {
    "guards": [
      "word_count_validator_bd4bdnun",
      "toxicity_detection_4yj4cdvu"
    ],
    "user": {
      "id": "7",
      "name": "mrunmay",
      "tags": [
        "coding",
        "software"
      ]
    }
  }
}

200

{
  "id": "text",
  "choices": [
    {
      "finish_reason": "stop",
      "index": 1,
      "message": {
        "role": "assistant",
        "content": "text"
      },
      "logprobs": {
        "content": [
          {
            "token": "text",
            "logprob": 1
          }
        ],
        "refusal": [
          {
            "token": "text",
            "logprob": 1
          }
        ]
      }
    }
  ],
  "created": 1,
  "model": "text",
  "service_tier": "scale",
  "system_fingerprint": "text",
  "object": "chat.completion",
  "usage": {
    "prompt_tokens": 1,
    "completion_tokens": 1,
    "total_tokens": 1,
    "prompt_tokens_details": {
      "cached_tokens": 1
    },
    "completion_tokens_details": {
      "reasoning_tokens": 1,
      "accepted_prediction_tokens": 1,
      "rejected_prediction_tokens": 1
    }
  }
}

Create embeddings

post

Creates an embedding vector representing the input text or token arrays.

Authorizations

Body

modelstringRequired

ID of the model to use for generating embeddings.

Example: text-embedding-ada-002

inputone ofRequired

stringOptional

The text to embed.

string[]Optional

Array of text strings to embed.

encoding_formatstring · enumOptional

The format to return the embeddings in.

Default: floatPossible values:

dimensionsinteger · min: 1 · max: 1536Optional

The number of dimensions the resulting embeddings should have.

Example: 1536

Responses

200

Successful response with embeddings

application/json

post

POST /v1/embeddings HTTP/1.1
Host: api.us-east-1.langdb.ai
Authorization: Bearer YOUR_SECRET_TOKEN
Content-Type: application/json
Accept: */*
Content-Length: 136

{
  "input": "The food was delicious and the waiter was kind.",
  "model": "text-embedding-ada-002",
  "encoding_format": "float",
  "dimensions": 1536
}

200

Successful response with embeddings

{
  "data": [
    {
      "embedding": [
        1
      ],
      "index": 1
    }
  ],
  "model": "text",
  "usage": {
    "prompt_tokens": 1,
    "total_tokens": 1
  }
}

Retrieve a list of threads

post

Authorizations

Header parameters

X-Project-IdstringRequired

LangDB project ID

Body

limitinteger · min: 1RequiredExample: 10

offsetintegerRequiredExample: 100

Responses

200

A list of threads with pagination info

application/json

post

POST /threads HTTP/1.1
Host: api.us-east-1.langdb.ai
Authorization: Bearer YOUR_SECRET_TOKEN
X-Project-Id: text
Content-Type: application/json
Accept: */*
Content-Length: 25

{
  "limit": 10,
  "offset": 100
}

200

A list of threads with pagination info

{
  "data": [
    {
      "id": "123e4567-e89b-12d3-a456-426614174000",
      "created_at": "2025-08-28T15:38:10.557Z",
      "updated_at": "2025-08-28T15:38:10.557Z",
      "model_name": "text",
      "project_id": "text",
      "score": 1,
      "title": "text",
      "user_id": "text"
    }
  ],
  "pagination": {
    "limit": 10,
    "offset": 100,
    "total": 10
  }
}

Retrieve messages for a specific thread

get

Authorizations

Path parameters

thread_idstring · uuidRequired

The ID of the thread to retrieve messages from

Header parameters

X-Project-IdstringRequired

LangDB project ID

Responses

200

A list of messages for the given thread

application/json

get

GET /threads/{thread_id}/messages HTTP/1.1
Host: api.us-east-1.langdb.ai
Authorization: Bearer YOUR_SECRET_TOKEN
X-Project-Id: text
Accept: */*

200

A list of messages for the given thread

[
  {
    "model_name": "gpt-4o-mini",
    "thread_id": "123e4567-e89b-12d3-a456-426614174000",
    "user_id": "langdb",
    "content_type": "Text",
    "content": "text",
    "content_array": [
      "text"
    ],
    "type": "system",
    "tool_call_id": "123e4567-e89b-12d3-a456-426614174000",
    "tool_calls": "text",
    "created_at": "2025-01-29 10:25:00.736000",
    "id": "123e4567-e89b-12d3-a456-426614174000"
  }
]

Retrieve the total cost for a specific thread

get

Authorizations

Path parameters

thread_idstring · uuidRequired

The ID of the thread for which to retrieve cost information

Header parameters

X-Project-IdstringRequired

LangDB project ID

Responses

200

The total cost and token usage for the specified thread

application/json

get

GET /threads/{thread_id}/cost HTTP/1.1
Host: api.us-east-1.langdb.ai
Authorization: Bearer YOUR_SECRET_TOKEN
X-Project-Id: text
Accept: */*

200

The total cost and token usage for the specified thread

{
  "total_cost": 0.022226999999999997,
  "total_output_tokens": 171,
  "total_input_tokens": 6725
}

Fetch analytics data

post

Authorizations

Header parameters

X-Project-IdstringRequired

LangDB project ID

Body

start_time_usinteger · int64Optional

Start time in microseconds.

Example: 1693062345678

end_time_usinteger · int64Optional

End time in microseconds.

Example: 1693082345678

Responses

200

Successful response

application/json

post

POST /analytics HTTP/1.1
Host: api.us-east-1.langdb.ai
Authorization: Bearer YOUR_SECRET_TOKEN
X-Project-Id: text
Content-Type: application/json
Accept: */*
Content-Length: 59

{
  "start_time_us": 1693062345678,
  "end_time_us": 1693082345678
}

200

Successful response

{
  "timeseries": [
    {
      "hour": "2025-02-20 18:00:00",
      "total_cost": 12.34,
      "total_requests": 1000,
      "avg_duration": 250.5,
      "duration": 245.7,
      "duration_p99": 750.2,
      "duration_p95": 500.1,
      "duration_p90": 400.8,
      "duration_p50": 200.3,
      "total_duration": 1,
      "total_input_tokens": 1,
      "total_output_tokens": 1,
      "error_rate": 1,
      "error_request_count": 1,
      "avg_ttft": 1,
      "ttft": 1,
      "ttft_p99": 1,
      "ttft_p95": 1,
      "ttft_p90": 1,
      "ttft_p50": 1,
      "tps": 1,
      "tps_p99": 1,
      "tps_p95": 1,
      "tps_p90": 1,
      "tps_p50": 1,
      "tpot": 0.85,
      "tpot_p99": 1.5,
      "tpot_p95": 1.2,
      "tpot_p90": 1,
      "tpot_p50": 0.75,
      "tag_tuple": [
        "text"
      ]
    }
  ],
  "start_time_us": 1,
  "end_time_us": 1
}

Fetch analytics summary

post

Authorizations

Header parameters

X-Project-IdstringRequired

LangDB project ID

Body

start_time_usinteger · int64OptionalExample: 1693062345678

end_time_usinteger · int64OptionalExample: 1693082345678

groupBystring[]RequiredExample: ["provider"]

Responses

200

Successful response

application/json

post

POST /analytics/summary HTTP/1.1
Host: api.us-east-1.langdb.ai
Authorization: Bearer YOUR_SECRET_TOKEN
X-Project-Id: text
Content-Type: application/json
Accept: */*
Content-Length: 82

{
  "start_time_us": 1693062345678,
  "end_time_us": 1693082345678,
  "groupBy": [
    "provider"
  ]
}

200

Successful response

{
  "summary": [
    {
      "tag_tuple": [
        "openai",
        "gpt-4"
      ],
      "total_cost": 156.78,
      "total_requests": 5000,
      "total_duration": 1250000,
      "avg_duration": 250,
      "duration": 245.5,
      "duration_p99": 750,
      "duration_p95": 500,
      "duration_p90": 400,
      "duration_p50": 200,
      "total_input_tokens": 100000,
      "total_output_tokens": 50000,
      "avg_ttft": 100,
      "ttft": 98.5,
      "ttft_p99": 300,
      "ttft_p95": 200,
      "ttft_p90": 150,
      "ttft_p50": 80,
      "tps": 10.5,
      "tps_p99": 20,
      "tps_p95": 15,
      "tps_p90": 12,
      "tps_p50": 8,
      "tpot": 0.85,
      "tpot_p99": 1.5,
      "tpot_p95": 1.2,
      "tpot_p90": 1,
      "tpot_p50": 0.75,
      "error_rate": 1,
      "error_request_count": 1
    }
  ],
  "start_time_us": 1,
  "end_time_us": 1
}

Get total usage

post

Authorizations

Header parameters

X-Project-IdstringRequired

LangDB project ID

Body

start_time_usinteger · int64OptionalExample: 1693062345678

end_time_usinteger · int64Optional

Responses

200

application/json

post

POST /usage/total HTTP/1.1
Host: api.us-east-1.langdb.ai
Authorization: Bearer YOUR_SECRET_TOKEN
X-Project-Id: text
Content-Type: application/json
Accept: */*
Content-Length: 47

{
  "start_time_us": 1693062345678,
  "end_time_us": 1
}

200

{
  "models": [
    {
      "provider": "openai",
      "model_name": "gpt-4o",
      "total_input_tokens": 3196182,
      "total_output_tokens": 74096,
      "total_cost": 10.4776979999,
      "cost_per_input_token": 3,
      "cost_per_output_token": 12
    }
  ],
  "total": {
    "total_input_tokens": 4181386,
    "total_output_tokens": 206547,
    "total_cost": 11.8904386859
  },
  "period_start": 1737504000000000,
  "period_end": 1740120949421000
}

Retrieve pricing information

get

Returns the pricing details for LangDB services.

Responses

200

Successful retrieval of pricing information

application/json

get

GET /pricing HTTP/1.1
Host: api.us-east-1.langdb.ai
Accept: */*

200

Successful retrieval of pricing information

{
  "model": "gpt-3.5-turbo-0125",
  "provider": "openai",
  "price": {
    "per_input_token": 0.5,
    "per_output_token": 1.5,
    "valid_from": null
  },
  "input_formats": [
    "text"
  ],
  "output_formats": [
    "text"
  ],
  "capabilities": [
    "tools"
  ],
  "type": "completions",
  "limits": {
    "max_context_size": 16385
  }
}

List models

get

Responses

200

application/json

get

GET /models HTTP/1.1
Host: api.us-east-1.langdb.ai
Accept: */*

200

{
  "object": "list",
  "data": [
    {
      "id": "o1-mini",
      "object": "model",
      "created": 1686935002,
      "owned_by": "openai"
    }
  ]
}

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