invalid byte sequence for encoding “UTF8”

Symptoms

Input contained a byte sequence that is not valid in the database’s server encoding. PostgreSQL raises SQLSTATE 22021 (character_not_in_repertoire).

• A byte sequence isn’t valid in the server encoding.
• Common loading data of a different encoding.
• The offending byte is shown in hex.

What the server log shows

ERROR:  invalid byte sequence for encoding "UTF8": 0xa9

Why PostgreSQL raises this — what the manual says

Section 23.3.3 Automatic Character Set Conversion Between Server and Client:

“the server will still check that incoming data is valid for that encoding”

PostgreSQL validates that incoming bytes form legal characters in the relevant encoding. A byte sequence that isn’t valid (e.g. mismatched client/server encoding) can’t be represented, so PostgreSQL reports 22021.

Common causes

• Loading data in a different encoding without conversion.
• client_encoding not matching the actual data.
• Binary/garbage bytes in a text field.

How to fix it

1. Set client_encoding to the source encoding so the server converts it.
2. Convert files to the server encoding first (e.g. iconv).
3. Strip invalid bytes before loading.

Related & next steps

• SQLSTATE 22021 — Character Not In Repertoire (full reference)
• Message: invalid byte sequence for encoding UTF8
• Glossary: Character encoding

Reference: PostgreSQL 18 Section 24.3 “Character Set Support”.