FASTA sequence extractor
Select exact FASTA identifiers and optional inclusive ranges while preserving record headers and sequence case.
Select complete FASTA records by exact identifier or extract the same one-based inclusive coordinate range from each selected record. Ranges cannot wrap or run beyond record boundaries. Alignment gaps count as positions. Output preserves the original identifier, full header and sequence case, with coordinates recorded separately in JSON and CSV. Existing annotations in a header are not recalculated after extraction. Runs locally without uploads or database lookup. Limit: 500000 combined input characters, 2000 records, 2000 validation issues, a 1000-symbol motif, 20000 matches and 10000000 symbol comparisons. Exceeding a limit rejects the complete report. Each export is limited to 3000000 characters; typed CSV allows 200000 values. Preview shows 200 rows. Processing stops after 10 seconds. Up to 500,000 characters. Review the settings before running.
Your result
How to use FASTA sequence extractor
- Paste valid FASTA and choose its alphabet.
- List exact identifiers in the desired order and optionally enter both coordinates.
- Review selected lengths and download the FASTA sequences and complete report.
Useful next steps
Coordinates include both endpoints
Coordinates start at 1. Both must fit every selected record; gaps count as positions. Leave both empty to extract whole records.
Preserve source identity
Names, full headers and case remain unchanged. Coordinates appear separately in JSON and CSV; annotations within headers are not rewritten.