Plain text and code
Merge TXT, Markdown, logs, subtitles, SQL and other UTF-8 text. Choose separators, line endings and optional filename headings.
FILE UTILITIES NO UPLOADS
File Merger by Type
Combine compatible text and structured data files into one clean download. Arrange the order, control how content joins, and preview your result—entirely in your browser.
Private by design Order matters Real format-aware merging
YOUR WORKSPACE
File Merger by Type
01
Choose a file format
Only compatible files can be combined in each mode.
Drag and drop files here or browse files from your device UTF-8 .txt, .md, .log and other plain-text files • Multiple files
Your files will appear here.
Use the arrows or drag a file to change the order.
Use the arrows or drag a file to change the order.
Original files are never modified. The order shown here is the order used for merging.
02
Configure your merge
Choose how one text file meets the next.
Union adds missing columns and fills blank values. Column names must be unique within each file.
JSON documents load into memory for structural merging. Limit: 24 MiB per file and 64 MiB total.
Every nonempty line is validated as JSON. Output uses UTF-8 and LF line endings. Invalid records stop the export.
BUILT FOR REAL FILES
One workflow. Four ways to merge.
Different file formats need different rules. Select the merge mode that matches the structure of your source files.
CSV and TSV tables
Combine rows without repeating headers. Match fields by name or position, track source filenames, optionally remove duplicates, and export as CSV or TSV.
JSON documents
Concatenate arrays, combine objects, deep-merge nested properties or collect individual documents with names.
JSONL and NDJSON
Combine newline-delimited JSON records, validate each line and stream the result without loading the full dataset.
Frequently asked questions
Are my files uploaded or stored online?
No. File reading, validation, merging and export happen in your browser. This standalone tool does not send your files to a server.
Can I combine CSV files with different columns?
Yes. Choose CSV / TSV and “Union by column name.” The merged file contains the combined set of column headers, with missing values left blank. Duplicate or ambiguous headers inside a source file are rejected.
Can I merge JSON files that contain different data types?
Yes. Use “Collect documents with filenames” to wrap each original document in an output array. For array concatenation or object merging, all files must have the corresponding top-level structure.
Can I merge PDFs, Word documents, videos or ZIP files here?
No. Those are binary or container formats and cannot safely be concatenated as text. Use a dedicated PDF, document, video or archive tool instead. HTML, XML, SRT and VTT may be concatenated as plain text, but the result is not guaranteed to be a valid combined document or subtitle track.
What happens with very large files?
Text, table and JSONL modes read input in chunks. In supported browsers, direct-to-disk saving avoids building one giant file in memory. Other browsers use a download fallback limited to 150 MiB of output. Structured JSON merging has stricter memory limits. Optional CSV duplicate removal also has a bounded memory index.