Want to export data from PostgreSQL table to JSON lines (JSONL / NDJSON / LDJSON)?
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JSON Lines text format (JSONL), also called Newline-delimited JSON (NDJSON), or Line-delimited JSON (LDJSON). JSON Lines files may be saved with the file extension .jsonl, *.ndjson, *.ldjson.
Export data from PostgreSQL table to JSON lines (JSONL / NDJSON / LDJSON)
Login to PostgreSQL -> Choose PostgreSQL table -> Set JSON lines file options -> Export PostgreSQL to JSON lines (JSONL / NDJSON / LDJSON)
Choose PostgreSQL and logon.
“Export From Table” for “PostgreSQL to JSON lines (JSONL / NDJSON / LDJSON)”.
Select JSON file type.
1. Choose PostgreSQL table.
2. Set JSON lines (JSONL / NDJSON / LDJSON) file options.
3. Set rows options.
4. Export PostgreSQL data to JSON lines (JSONL / NDJSON / LDJSON) table.
After exporting, you can view output JSON lines (JSONL / NDJSON / LDJSON) file.
More tools for JSONL / NDJSON / LDJSON.
Download Withdata DBToFile
PostgreSQL → JSON Lines reference
Type mapping
| Value kind | in PostgreSQL | in JSON Lines |
|---|---|---|
| Int | integer | 1234 (number) |
| Bigint | bigint | 9007199254740993 |
| Decimal | numeric(p,s) | 1234.56 (number) |
| Float | double precision | 1.234e10 (number) |
| Text | varchar(n) | "text" (string) |
| Long text | text | "multi-line\ntext" |
| Date | date | "2026-09-18" (string) |
| Datetime | timestamp | "2026-09-18T14:30:00Z" (string) |
| Binary | bytea | "base64:..." (string) |
| Boolean | boolean | true / false (boolean) |
| JSON | jsonb | nested object on the same line |
Dialect differences
PostgreSQL is a database server and JSON Lines is a file format, so the gap is wider than a dialect difference - the rows below are where values and structure stop lining up.
| Property | in PostgreSQL | in JSON Lines |
|---|---|---|
| port | 5432 | — |
| identifiers | "double quotes" | Double quotes; backslash escapes (a newline inside a string... |
| row limit | LIMIT n | — |
| dates | timestamp, timestamptz, date, time | No date type: dates arrive as strings |
| long text | TEXT | — |
| binary | BYTEA | Not supported natively - base64 inside a string |
| separator | — | Newline between records |
| encoding | — | UTF-8 by definition |
| typing | — | Same as JSON, but records cannot nest across lines |
| shape | Tables of rows and columns | Flat stream |
| ceiling | — | Streams, so it scales past what a single JSON document can ... |
Command line
| Side | Command |
|---|---|
| PostgreSQL | pg_dump or COPY ... TO |
| PostgreSQL (load) | COPY ... FROM |
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