Free online TOML to ACCDB converter

Applications that require a Microsoft Access database may receive configuration or data records in TOML, so the values must be parsed and inserted into an .accdb file. This is a data-structure conversion rather than a direct format change because TOML has no tables, indexes, or relationships equivalent to those in Access.

What the TOML format is

TOML, short for Tom's Obvious Minimal Language, is a human-readable configuration format built from key-value pairs, tables, arrays, strings, numbers, booleans, and dates. Developers use it for application settings, build tools, package managers, deployment files, and project metadata.

Common producers and consumers include Rust's Cargo through Cargo.toml, Python packaging tools through pyproject.toml, static-site generators, game tools, and custom applications. You normally encounter TOML as a configuration file rather than as a database export.

What the ACCDB format is

ACCDB is the Microsoft Access database format used by Access 2007 and later. It stores tables, queries, forms, reports, indexes, relationships, macros, and—in supported configurations—attachments and multivalued fields.

An ACCDB file is useful when users need to edit records in Microsoft Access, run saved queries, print reports, or share a small relational database without deploying a server database system. Access requires the matching Microsoft Access Database Engine or Microsoft Access installation to create and edit ACCDB files.

How to actually convert TOML to ACCDB

Because there is no universal one-to-one mapping, first decide which TOML sections become tables and which keys become columns. A simple TOML file containing an array of tables is the easiest case:

[[products]]
name = 'Keyboard'
price = 49.95
available = true

[[products]]
name = 'Mouse'
price = 19.95
available = false

For this structure, Python 3.11 or later can parse TOML with its built-in tomllib module. Install the Microsoft Access ODBC driver and pyodbc, then run a script that creates the database and inserts the records:

import tomllib
import pyodbc

with open('products.toml', 'rb') as source:
    data = tomllib.load(source)

rows = data['products']
fields = ['name', 'price', 'available']

def quote_identifier(value):
    return '[' + value.replace(']', ']]') + ']'

def sql_type(values):
    if all(isinstance(value, bool) for value in values):
        return 'YESNO'
    if all(isinstance(value, (int, float)) and not isinstance(value, bool) for value in values):
        return 'DOUBLE'
    return 'LONGTEXT'

database = 'products.accdb'
connection_string = (
    'DRIVER={Microsoft Access Driver (*.mdb, *.accdb)};'
    'DBQ=' + database + ';'
)

with pyodbc.connect(connection_string, autocommit=True) as connection:
    cursor = connection.cursor()
    columns = ['[id] COUNTER PRIMARY KEY']
    for field in fields:
        values = [row.get(field) for row in rows if row.get(field) is not None]
        columns.append(quote_identifier(field) + ' ' + sql_type(values))
    cursor.execute('CREATE TABLE [products] (' + ', '.join(columns) + ')')

    placeholders = ', '.join('?' for field in fields)
    column_list = ', '.join(quote_identifier(field) for field in fields)
    statement = 'INSERT INTO [products] (' + column_list + ') VALUES (' + placeholders + ')'
    for row in rows:
        cursor.execute(statement, [row.get(field) for field in fields])

Save the script as toml_to_accdb.py and execute python toml_to_accdb.py. The script creates products.accdb, adds an auto-number primary key, infers basic Access types, and inserts the array entries.

For more complex files, normalize the data before loading it. A TOML table such as [server] can become a one-row server table; an array such as [[users]] can become a users table; and nested tables should usually become related tables with primary and foreign keys. Do not store every nested object in one text column unless preserving the original configuration is more important than querying it.

Microsoft Access can then open the result through File → Open → Browse. If the data has first been written to CSV, use External Data → New Data Source → From File → Text File, select the delimiter and field types, and choose a primary key during import.

You can also try the free converter on 101convert.com without installing software. Online conversion is suitable only when the service supports the TOML structure and the resulting database schema meets your needs; validate the generated tables and values before using the file.

Quality, compatibility, and limitations

A TOML file does not define relational keys, indexes, field lengths, or table relationships, so those elements must be designed during conversion. TOML dates, local times, arrays, inline tables, multiline strings, and mixed-type arrays may require explicit handling rather than automatic type inference.

Access text fields can store Unicode, but reserved words and characters in TOML keys should be escaped or renamed before creating SQL identifiers. The Microsoft Access ODBC driver is normally available on Windows; 32-bit and 64-bit Python, driver, and Office installations must use compatible architectures.

After loading, open the ACCDB file in Access and verify row counts, null values, dates, decimal precision, Unicode characters, and relationships. Keep the original TOML file because the generated database generally cannot reproduce the original formatting, comments, key order, or exact nested structure.