Compact API

POST

compact

Compact context

curl --request POST \
  --url https://api.morphllm.com/v1/compact \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "input": "def hello():\n    return 1\n\ndef unused():\n    pass\n\ndef world():\n    return 2",
  "messages": [
    {
      "role": "user",
      "content": "Help me build a Node.js API with JWT auth"
    }
  ],
  "query": "hello function",
  "compression_ratio": 0.5,
  "preserve_recent": 0,
  "compress_system_messages": false,
  "include_line_ranges": true,
  "include_markers": true,
  "model": "morph-compactor"
}
'

import requests

url = "https://api.morphllm.com/v1/compact"

payload = {
    "input": "def hello():
    return 1

def unused():
    pass

def world():
    return 2",
    "messages": [
        {
            "role": "user",
            "content": "Help me build a Node.js API with JWT auth"
        }
    ],
    "query": "hello function",
    "compression_ratio": 0.5,
    "preserve_recent": 0,
    "compress_system_messages": False,
    "include_line_ranges": True,
    "include_markers": True,
    "model": "morph-compactor"
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    input: 'def hello():\n    return 1\n\ndef unused():\n    pass\n\ndef world():\n    return 2',
    messages: [{role: 'user', content: 'Help me build a Node.js API with JWT auth'}],
    query: 'hello function',
    compression_ratio: 0.5,
    preserve_recent: 0,
    compress_system_messages: false,
    include_line_ranges: true,
    include_markers: true,
    model: 'morph-compactor'
  })
};

fetch('https://api.morphllm.com/v1/compact', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.morphllm.com/v1/compact",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'input' => 'def hello():
    return 1

def unused():
    pass

def world():
    return 2',
    'messages' => [
        [
                'role' => 'user',
                'content' => 'Help me build a Node.js API with JWT auth'
        ]
    ],
    'query' => 'hello function',
    'compression_ratio' => 0.5,
    'preserve_recent' => 0,
    'compress_system_messages' => false,
    'include_line_ranges' => true,
    'include_markers' => true,
    'model' => 'morph-compactor'
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.morphllm.com/v1/compact"

	payload := strings.NewReader("{\n  \"input\": \"def hello():\\n    return 1\\n\\ndef unused():\\n    pass\\n\\ndef world():\\n    return 2\",\n  \"messages\": [\n    {\n      \"role\": \"user\",\n      \"content\": \"Help me build a Node.js API with JWT auth\"\n    }\n  ],\n  \"query\": \"hello function\",\n  \"compression_ratio\": 0.5,\n  \"preserve_recent\": 0,\n  \"compress_system_messages\": false,\n  \"include_line_ranges\": true,\n  \"include_markers\": true,\n  \"model\": \"morph-compactor\"\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://api.morphllm.com/v1/compact")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"input\": \"def hello():\\n    return 1\\n\\ndef unused():\\n    pass\\n\\ndef world():\\n    return 2\",\n  \"messages\": [\n    {\n      \"role\": \"user\",\n      \"content\": \"Help me build a Node.js API with JWT auth\"\n    }\n  ],\n  \"query\": \"hello function\",\n  \"compression_ratio\": 0.5,\n  \"preserve_recent\": 0,\n  \"compress_system_messages\": false,\n  \"include_line_ranges\": true,\n  \"include_markers\": true,\n  \"model\": \"morph-compactor\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.morphllm.com/v1/compact")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"input\": \"def hello():\\n    return 1\\n\\ndef unused():\\n    pass\\n\\ndef world():\\n    return 2\",\n  \"messages\": [\n    {\n      \"role\": \"user\",\n      \"content\": \"Help me build a Node.js API with JWT auth\"\n    }\n  ],\n  \"query\": \"hello function\",\n  \"compression_ratio\": 0.5,\n  \"preserve_recent\": 0,\n  \"compress_system_messages\": false,\n  \"include_line_ranges\": true,\n  \"include_markers\": true,\n  \"model\": \"morph-compactor\"\n}"

response = http.request(request)
puts response.read_body

{
  "id": "cmpr-7373faf8af65",
  "object": "compact",
  "model": "morph-compactor",
  "output": "def hello():\n    return 1\n(filtered 3 lines)\ndef world():\n    return 2",
  "messages": [
    {
      "role": "user",
      "content": "def hello():\n    return 1\n(filtered 3 lines)\ndef world():\n    return 2",
      "compacted_line_ranges": [
        {
          "start": 4,
          "end": 6
        }
      ],
      "kept_line_ranges": []
    }
  ],
  "usage": {
    "input_tokens": 101,
    "output_tokens": 65,
    "compression_ratio": 0.644,
    "processing_time_ms": 109
  }
}

{
  "error": {
    "code": "invalid_request_error",
    "message": "The request body is missing the `model` field."
  }
}

{
  "error": {
    "code": "unauthorized",
    "message": "Invalid API key provided."
  }
}

{
  "error": {
    "code": "rate_limited",
    "message": "Too many requests. Retry in 12 seconds."
  }
}

{
  "error": {
    "code": "internal_error",
    "message": "Something went wrong on our side."
  }
}

Overview

Compact compresses chat history and code context at 33,000 tok/s by removing irrelevant lines. Every surviving line is byte-for-byte identical to the original input. 100K tokens compresses in under 2 seconds. Pass query to tell the model what matters for the next LLM call. Without it, the model auto-detects from the last user message.

Usage Examples

import { MorphClient } from '@morphllm/morphsdk';

const morph = new MorphClient({ apiKey: "YOUR_API_KEY" });

const result = await morph.compact({
  input: chatHistory,
  query: "How do I validate JWT tokens?",
  compressionRatio: 0.5,
  preserveRecent: 3,
});

// result.output is the compressed text — pass it to your LLM

from openai import OpenAI

client = OpenAI(
    api_key="YOUR_API_KEY",
    base_url="https://api.morphllm.com/v1",
)

response = client.chat.completions.create(
    model="morph-compactor",
    messages=[{"role": "user", "content": chat_history}],
)

compressed = response.choices[0].message.content

import requests

response = requests.post(
    "https://api.morphllm.com/v1/compact",
    headers={"Authorization": "Bearer YOUR_API_KEY"},
    json={
        "input": source_code,
        "query": "authentication",
        "compression_ratio": 0.5,
        "preserve_recent": 0,
    },
)

data = response.json()
print(data["output"])

for r in data["messages"][0]["compacted_line_ranges"]:
    print(f"  lines {r['start']}-{r['end']} removed")

curl -X POST "https://api.morphllm.com/v1/compact" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "input": "def hello():\n    return 1\n\ndef unused():\n    pass\n\ndef world():\n    return 2",
    "query": "hello function",
    "compression_ratio": 0.5,
    "preserve_recent": 0
  }'

keepContext Tags

Wrap sections you never want compressed in <keepContext> / </keepContext> tags. Tagged content survives compression verbatim regardless of the compression ratio.

<keepContext>
// CRITICAL: Auth middleware — do not compress
function authenticate(req, res, next) {
  const token = req.headers.authorization?.split(' ')[1];
  if (!token) return res.status(401).json({ error: 'No token' });
  req.user = jwt.verify(token, process.env.JWT_SECRET);
  next();
}
</keepContext>

The response includes kept_line_ranges showing which lines were force-preserved.

Compatible Endpoints

Compact also works through OpenAI-compatible endpoints with model: "morph-compactor":

Endpoint	Format	Use with
`POST /v1/compact`	Native Morph format	Direct HTTP, Morph SDK
`POST /v1/responses`	OpenAI Responses API	Any OpenAI SDK (`client.responses.create()`)
`POST /v1/chat/completions`	OpenAI Chat Completions	Any OpenAI-compatible client

See the full Compact documentation for SDK reference, best practices, and advanced usage.

Authorizations

Authorization

string

header

required

Morph API key, passed as Authorization: Bearer sk-.... Create keys at https://www.morphllm.com/dashboard/api-keys.

Body

application/json

Compact request with text or messages to compress

Text or conversation to compress, plus the knobs controlling how aggressively lines are pruned.

input

string

default:def hello(): return 1 def unused(): pass def world(): return 2

Text to compact. One of input or messages is required.

Example:

"def hello():\n return 1\n\ndef unused():\n pass\n\ndef world():\n return 2"

messages

object[]

Conversation messages to compact. Takes priority over input.

Show child attributes

Example:

[
  {
    "role": "user",
    "content": "Help me build a Node.js API with JWT auth"
  }
]

query

string

default:hello function

Focus query for relevance-based pruning. Lines relevant to this query are kept.

Example:

"hello function"

compression_ratio

number

default:0.5

Fraction of input to keep. 0.3 = aggressive, 0.7 = light.

Example:

0.5

preserve_recent

integer

default:2

Keep last N messages uncompressed.

Example:

0

compress_system_messages

boolean

default:false

When true, system messages are also compressed. By default they are preserved verbatim.

Example:

false

include_line_ranges

boolean

default:true

Include compacted_line_ranges in response.

Example:

true

include_markers

boolean

default:true

Include (filtered N lines) text markers. When false, gaps become empty lines.

Example:

true

model

string

default:morph-compactor

Model ID.

Example:

"morph-compactor"

Response

Compact response with compressed output and metadata

Compacted output, per-message line ranges, and usage statistics.

string

required

Unique identifier for the compact request

Example:

"cmpr-7373faf8af65"

object

string

required

Object type, always compact

Example:

"compact"

model

string

required

Model used

Example:

"morph-compactor"

output

string

required

All compacted messages joined into a single string

Example:

"def hello():\n return 1\n(filtered 3 lines)\ndef world():\n return 2"

messages

object[]

required

Per-message compaction results

Show child attributes

Example:

[
  {
    "role": "user",
    "content": "def hello():\n    return 1\n(filtered 3 lines)\ndef world():\n    return 2",
    "compacted_line_ranges": [{ "start": 4, "end": 6 }],
    "kept_line_ranges": []
  }
]

usage

object

required

Usage statistics — token counts and timing for a single compaction.

Show child attributes

Example:

{
  "input_tokens": 101,
  "output_tokens": 65,
  "compression_ratio": 0.644,
  "processing_time_ms": 109
}

Compact context

curl --request POST \
  --url https://api.morphllm.com/v1/compact \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "input": "def hello():\n    return 1\n\ndef unused():\n    pass\n\ndef world():\n    return 2",
  "messages": [
    {
      "role": "user",
      "content": "Help me build a Node.js API with JWT auth"
    }
  ],
  "query": "hello function",
  "compression_ratio": 0.5,
  "preserve_recent": 0,
  "compress_system_messages": false,
  "include_line_ranges": true,
  "include_markers": true,
  "model": "morph-compactor"
}
'

import requests

url = "https://api.morphllm.com/v1/compact"

payload = {
    "input": "def hello():
    return 1

def unused():
    pass

def world():
    return 2",
    "messages": [
        {
            "role": "user",
            "content": "Help me build a Node.js API with JWT auth"
        }
    ],
    "query": "hello function",
    "compression_ratio": 0.5,
    "preserve_recent": 0,
    "compress_system_messages": False,
    "include_line_ranges": True,
    "include_markers": True,
    "model": "morph-compactor"
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    input: 'def hello():\n    return 1\n\ndef unused():\n    pass\n\ndef world():\n    return 2',
    messages: [{role: 'user', content: 'Help me build a Node.js API with JWT auth'}],
    query: 'hello function',
    compression_ratio: 0.5,
    preserve_recent: 0,
    compress_system_messages: false,
    include_line_ranges: true,
    include_markers: true,
    model: 'morph-compactor'
  })
};

fetch('https://api.morphllm.com/v1/compact', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.morphllm.com/v1/compact",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'input' => 'def hello():
    return 1

def unused():
    pass

def world():
    return 2',
    'messages' => [
        [
                'role' => 'user',
                'content' => 'Help me build a Node.js API with JWT auth'
        ]
    ],
    'query' => 'hello function',
    'compression_ratio' => 0.5,
    'preserve_recent' => 0,
    'compress_system_messages' => false,
    'include_line_ranges' => true,
    'include_markers' => true,
    'model' => 'morph-compactor'
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.morphllm.com/v1/compact"

	payload := strings.NewReader("{\n  \"input\": \"def hello():\\n    return 1\\n\\ndef unused():\\n    pass\\n\\ndef world():\\n    return 2\",\n  \"messages\": [\n    {\n      \"role\": \"user\",\n      \"content\": \"Help me build a Node.js API with JWT auth\"\n    }\n  ],\n  \"query\": \"hello function\",\n  \"compression_ratio\": 0.5,\n  \"preserve_recent\": 0,\n  \"compress_system_messages\": false,\n  \"include_line_ranges\": true,\n  \"include_markers\": true,\n  \"model\": \"morph-compactor\"\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://api.morphllm.com/v1/compact")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"input\": \"def hello():\\n    return 1\\n\\ndef unused():\\n    pass\\n\\ndef world():\\n    return 2\",\n  \"messages\": [\n    {\n      \"role\": \"user\",\n      \"content\": \"Help me build a Node.js API with JWT auth\"\n    }\n  ],\n  \"query\": \"hello function\",\n  \"compression_ratio\": 0.5,\n  \"preserve_recent\": 0,\n  \"compress_system_messages\": false,\n  \"include_line_ranges\": true,\n  \"include_markers\": true,\n  \"model\": \"morph-compactor\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.morphllm.com/v1/compact")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"input\": \"def hello():\\n    return 1\\n\\ndef unused():\\n    pass\\n\\ndef world():\\n    return 2\",\n  \"messages\": [\n    {\n      \"role\": \"user\",\n      \"content\": \"Help me build a Node.js API with JWT auth\"\n    }\n  ],\n  \"query\": \"hello function\",\n  \"compression_ratio\": 0.5,\n  \"preserve_recent\": 0,\n  \"compress_system_messages\": false,\n  \"include_line_ranges\": true,\n  \"include_markers\": true,\n  \"model\": \"morph-compactor\"\n}"

response = http.request(request)
puts response.read_body

{
  "id": "cmpr-7373faf8af65",
  "object": "compact",
  "model": "morph-compactor",
  "output": "def hello():\n    return 1\n(filtered 3 lines)\ndef world():\n    return 2",
  "messages": [
    {
      "role": "user",
      "content": "def hello():\n    return 1\n(filtered 3 lines)\ndef world():\n    return 2",
      "compacted_line_ranges": [
        {
          "start": 4,
          "end": 6
        }
      ],
      "kept_line_ranges": []
    }
  ],
  "usage": {
    "input_tokens": 101,
    "output_tokens": 65,
    "compression_ratio": 0.644,
    "processing_time_ms": 109
  }
}

{
  "error": {
    "code": "invalid_request_error",
    "message": "The request body is missing the `model` field."
  }
}

{
  "error": {
    "code": "unauthorized",
    "message": "Invalid API key provided."
  }
}

{
  "error": {
    "code": "rate_limited",
    "message": "Too many requests. Retry in 12 seconds."
  }
}

{
  "error": {
    "code": "internal_error",
    "message": "Something went wrong on our side."
  }
}

Get Started

Models

API Reference

Integrations

Overview

Usage Examples

keepContext Tags

Compatible Endpoints

Authorizations

Body

Response

​Overview

​Usage Examples

​keepContext Tags

​Compatible Endpoints

Authorizations

Body

Response

Overview

Usage Examples

keepContext Tags

Compatible Endpoints