Is converting DDB to PostgreSQL free?

Yes. Files up to 10MB convert free with no account. There is a limit of five conversions per day per IP address.

Will my DDB data keep its types in PostgreSQL?

Yes — that is the point. Whole numbers, decimals, dates and booleans are mapped to real PostgreSQL types rather than everything becoming text. The mapping table above shows exactly what you get.

Do you store my file?

No. The file is written to a temporary directory, converted, and the directory is deleted as soon as your download has been sent.

Convert DDB to PostgreSQL

Upload a .duckdb or .ddb file and get back a PostgreSQL SQL script you can load straight into your database. Types are preserved rather than flattened to text. Free, no registration, up to 10MB.

1Upload your file

Click to upload or drag and drop

CSV, Excel, SQLite, SQL, DBF (max 10 MB)

2Choose target format

How your data is typed in PostgreSQL

Generated from the converter's own PostgreSQL type mapping — this is what it actually emits, not an example.

Your data	PostgreSQL type
Whole number	BIGINT
Decimal (money)	NUMERIC(10,2)
Floating point	DOUBLE PRECISION
True / false	BOOLEAN
Date	DATE
Date and time	TIMESTAMP
Short text	TEXT
Long text	TEXT
Binary data	BYTEA

Working from a .ddb file

.ddb is the short form of the DuckDB extension, and DuckDB itself does not care what you call a database file. The uploader does: it routes on the extension alone, so the name you saved under decides which reader ever sees the file.

→.ddb and .duckdb both reach the DuckDB reader and are read identically. Nothing inside the file records which of the two you chose - the storage version is in the header, the name is not.
→One file is this format's whole promise, so make sure it really is one file before you send it: closing the DuckDB CLI cleanly, or running CHECKPOINT first, folds the write-ahead log back into the database itself.
→A file with no extension at all, which DuckDB is perfectly happy to create, is not recognised as anything and is refused before it is read.

What the PostgreSQL script contains

The conversion produces one dump.sql with a README beside it, zipped. It is a script you can open, grep and edit before you run it rather than an archive a tool has to unpack, and it is deliberately sparing in what it declares.

→Every string column is declared TEXT, whatever length the source declared for it. PostgreSQL stores a short value in a TEXT column exactly as cheaply as in a VARCHAR, and an unbounded column cannot reject a row on load for being a few characters too long.
→Identifiers are all double-quoted, and even so a name on PostgreSQL's reserved list is given a trailing underscore: a column called user arrives as user_, order as order_, limit as limit_.
→A decimal column whose source declared no scale is given six decimal places rather than none, keeping whatever precision it did declare: NUMERIC(10,6) from a source that said 10, and NUMERIC(18,6) from one that declared neither. A scale of zero would have the server round 19.99 to 20 as it loaded.

Reading DDB

→Types, primary keys and NOT NULL constraints are read from the database.
→The file is opened read-only, so your upload is never modified or upgraded in place.

Writing PostgreSQL

→Backslashes are left alone, because PostgreSQL treats them as ordinary characters — doubling them would corrupt every Windows path.
→Auto-increment columns become GENERATED BY DEFAULT AS IDENTITY.
→Binary data is written as bytea, and identifiers respect the 63-character limit.

What you get

A ZIP containing dump.sql, plus a README with the exact command to load it. If anything about your data needed a judgement call, a _warnings.txt explains it.

Load this dump into PostgreSQL:

  psql -U USER -d DATABASE -f dump.sql

Create the database first if it does not exist:

  createdb -U USER DATABASE

Questions

Is converting DDB to PostgreSQL free?: Yes. Files up to 10MB convert free with no account. There is a limit of five conversions per day per IP address.
Will my DDB data keep its types in PostgreSQL?: Yes — that is the point. Whole numbers, decimals, dates and booleans are mapped to real PostgreSQL types rather than everything becoming text. The mapping table above shows exactly what you get.
Do you store my file?: No. The file is written to a temporary directory, converted, and the directory is deleted as soon as your download has been sent.