YAML to TOML Converter

What does the YAML to TOML Converter do?

The YAML to TOML Converter on blueutils.com transforms YAML configuration files, manifests, and structured documents into valid TOML (Tom's Obvious, Minimal Language) v1.0.0 syntax. It maps YAML key-value dictionaries to TOML tables, converts nested objects into table sections ([table]), and handles arrays of objects as array tables ([[array_table]]), producing clean configuration files for Rust Cargo, Python Poetry, Hugo, and cloud environments.

Core Concepts

Understanding conversion rules between YAML and TOML ensures seamless configuration interoperability:

• Table Formatting: YAML dictionaries are represented as TOML key-value pairs (key = "value"). Nested dictionaries automatically create TOML table headers ([server.database]).
• Array of Tables: Sequences containing dictionaries are serialized into TOML array of tables syntax ([[servers]]).
• Scalar Type Preservation: Numbers, booleans, floating-point decimals, and ISO dates maintain their native types across conversion.

How to use the tool?

1. Paste or Upload YAML Payload: Paste your YAML configuration into the left Raw YAML Input editor, click Upload, or click Sample.
2. Instant Conversion: The converter parses YAML mappings, nested sections, and scalar types into standard TOML tables automatically in real time.
3. Copy or Export: Click Copy to copy the TOML output to your clipboard or Download to save your formatted blueutils-export.toml configuration file.

Related Developer Utilities

If you work with configuration files, data serialization, and DevOps manifests, explore these related tools:

• YAML to JSON Converter: Convert YAML configuration files into standardized JSON documents.
• YAML to Dotenv Converter: Flatten nested YAML configurations into .env environment variables.
• YAML to Markdown Converter: Convert YAML sequences and mappings into Markdown tables and lists.
• YAML Syntax Validator: Validate YAML indentation rules and detect syntax errors.

REST API Integration

blueutils.com provides a free REST API endpoint (POST https://blueutils.com/api/yaml/to-toml) to programmatically convert raw YAML documents and configurations into TOML v1.0.0 format.

API Request Parameters

API Request Payload Examples

cURL (Using Raw String)

curl -X POST https://blueutils.com/api/yaml/to-toml \
  -H "Content-Type: application/json" \
  -d '{
    "rawText": "package:\n  name: blueutils\n  version: 1.0.0\n\nserver:\n  host: 0.0.0.0\n  port: 8080"
  }'

cURL (Using Direct Object)

curl -X POST https://blueutils.com/api/yaml/to-toml \
  -H "Content-Type: application/json" \
  -d '{
    "yaml": {
      "package": { "name": "blueutils", "version": "1.0.0" },
      "server": { "host": "0.0.0.0", "port": 8080 }
    }
  }'

Python

import requests

url = "https://blueutils.com/api/yaml/to-toml"
payload = {
    "rawText": "package:\n  name: blueutils\n  version: 1.0.0\n\nserver:\n  host: 0.0.0.0\n  port: 8080"
}
headers = {"Content-Type": "application/json"}
response = requests.post(url, json=payload, headers=headers)
print(response.json())

Java

import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;

public class Main {
    public static void main(String[] args) throws Exception {
        String jsonPayload = """
            {
                "rawText": "package:\\n  name: blueutils\\n  version: 1.0.0\\n\\nserver:\\n  host: 0.0.0.0\\n  port: 8080"
            }
            """;

        HttpClient client = HttpClient.newHttpClient();
        HttpRequest request = HttpRequest.newBuilder()
            .uri(URI.create("https://blueutils.com/api/yaml/to-toml"))
            .header("Content-Type", "application/json")
            .POST(HttpRequest.BodyPublishers.ofString(jsonPayload))
            .build();

        HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
        System.out.println(response.body());
    }
}

API Response Parameters

API Response Payload Examples

Success Response (HTTP 200 OK)

{
  "isValid": true,
  "message": "Successfully converted YAML data to TOML (2 tables).",
  "toml": "[package]\nname = \"blueutils\"\nversion = \"1.0.0\"\n\n[server]\nhost = \"0.0.0.0\"\nport = 8080",
  "data": {
    "package": {
      "name": "blueutils",
      "version": "1.0.0"
    },
    "server": {
      "host": "0.0.0.0",
      "port": 8080
    }
  },
  "tableCount": 2,
  "originalSize": 58,
  "resultSize": 52
}

Validation Failure Response (HTTP 400 Bad Request)

{
  "isValid": false,
  "error": "Invalid input: YAML payload cannot be empty."
}

Rate Limit Exceeded Response (HTTP 429 Too Many Requests)

{
  "error": "API rate limit exceeded. Please wait or contact support@blueutils.com."
}

Why use an API to convert YAML to TOML?

Integrating the YAML to TOML converter API into continuous integration pipelines, multi-language configuration synchronizers, and build systems provides concrete benefits:

• Cross-Ecosystem Config Migration: Simplifies synchronizing service configurations across YAML-based tools (Kubernetes, Docker Compose, GitHub Actions) and TOML-based runtimes (Rust Cargo, Python Poetry, Hugo).
• Optimized Token Efficiency for AI Agents: AI assistants and configuration bots can convert YAML specs to TOML via lightweight API requests rather than generating verbose TOML syntax token-by-token.
• Strict TOML Standard Compliance: Guarantees syntax compliance with TOML v1.0.0, avoiding manual table hierarchy errors and unquoted string mistakes.

Native Usage

How to convert YAML files into TOML configurations locally in terminal environments:

Windows (CMD / PowerShell)

# Convert YAML to TOML using Python in PowerShell
python -c "
import yaml, toml
data = yaml.safe_load(open('config.yaml'))
with open('config.toml', 'w') as f:
    toml.dump(data, f)
print('Converted config.yaml to config.toml')
"

Linux / Unix (Bash)

# Convert YAML to TOML using yq and tomlq
yq -o=json config.yaml | python3 -c "import sys, json, toml; print(toml.dumps(json.load(sys.stdin)))" > config.toml

Python

Using PyYAML and toml:

import yaml
import toml

with open("config.yaml", "r") as f:
    data = yaml.safe_load(f)

toml_string = toml.dumps(data)
with open("config.toml", "w") as f:
    f.write(toml_string)

print("Converted YAML to TOML successfully.")

Java

Using Jackson with dataformat.yaml and dataformat.toml:

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.dataformat.yaml.YAMLMapper;
import com.fasterxml.jackson.dataformat.toml.TomlMapper;
import java.io.File;

public class YamlToTomlExample {
    public static void main(String[] args) throws Exception {
        YAMLMapper yamlMapper = new YAMLMapper();
        JsonNode root = yamlMapper.readTree(new File("config.yaml"));

        TomlMapper tomlMapper = new TomlMapper();
        tomlMapper.writeValue(new File("config.toml"), root);

        System.out.println("Converted config.yaml to config.toml successfully.");
    }
}