Four Tools. One Canvas. One Export.

Fastp replaces both FastQC and a separate trimming tool in a single step. It produces filtered reads alongside a JSON QC report that MultiQC reads directly. FastQC, Fastp, your aligner of choice, and MultiQC are all pre-configured in GenXflo.

What Makes Fastp Different and When to Choose It

Both Fastp and BBDuk remove adapter sequences and quality-trim reads. The practical difference is that Fastp combines QC reporting with trimming in a single pass, writing a JSON file that MultiQC reads natively. This removes the need for a separate FastQC step before trimming if the Fastp JSON report is sufficient for your QC review.

BBDuk offers more granular control over k-mer-based adapter matching and contaminant filtering, which is useful when your adapter sequences are non-standard or when you need to filter reads against a custom contaminant reference. For most standard Illumina library preparations with known adapter sequences, Fastp's automatic adapter detection and per-read quality sliding window trimming cover the same ground with less configuration.

FastQC

Pre-trim overview
A FastQC run before Fastp gives you a visual overview of the raw data before any processing. Some teams skip this step because Fastp's JSON report contains similar per-base quality information. Including both gives you a clear before-and-after comparison in the final MultiQC report.

Fastp

QC and trimming in one step
Removes adapter sequences through automatic detection or a specified adapter file, quality-trims reads using a sliding window, filters reads below a minimum length, and writes a JSON QC report alongside the filtered FASTQ files. All parameters are configured through the GenXflo form and documented in the exported config file. Fastp is notably fast and handles paired-end reads correctly without separate handling of read 1 and read 2.

Aligner

Your choice on the canvas
HISAT2, STAR, BWA, and Bowtie2 are all in the GenXflo library. Drag any one of them onto the canvas and connect the Fastp trimmed output to it. GenXflo validates the FASTQ output type compatibility at the connection point. Swap aligners without changing any other part of the pipeline.

MultiQC

Aggregated report
Reads Fastp JSON files natively and aggregates them alongside FastQC HTML outputs into a single comparative report. In GenXflo, MultiQC receives these files through channel connections rather than directory scans, ensuring every sample appears in the final report.

Fastp in a Script vs Fastp in GenXflo

Without GenXflo

  • Fastp JSON files require manual routing to MultiQC, easy to miss samples
  • Adapter detection mode and quality thresholds hardcoded per experiment
  • No container: Fastp version inconsistent across team environments
  • Trimmed FASTQ paths need manual coordination before the aligner can find them
  • No documented link between trimming parameters and alignment results

With GenXflo

  • Fastp JSON routes to MultiQC through a canvas channel connection automatically
  • Adapter and quality parameters configured in the form and documented in the exported config
  • Container image pins the exact Fastp version across all environments
  • Trimmed FASTQ routing to the aligner handled by channel definitions in the exported code
  • Every trimming parameter documented in the config file alongside the workflow script

Questions About Fastp and GenXflo

Should I use Fastp or BBDuk for adapter trimming in GenXflo?

Both are in the GenXflo library. Fastp is simpler to configure for standard Illumina libraries with automatic adapter detection and produces a JSON QC report that MultiQC reads natively. BBDuk offers more control over k-mer-based matching and contaminant filtering. For most RNA-seq and DNA sequencing experiments with standard adapters, Fastp requires less configuration and integrates more cleanly with MultiQC.

Does MultiQC read Fastp JSON output natively in GenXflo?

Yes. MultiQC supports Fastp JSON output directly. In GenXflo, the Fastp JSON files route to MultiQC through a canvas channel connection, so every sample's trimming statistics appear in the final aggregated report without any manual file collection.

Which aligners can I connect to Fastp in GenXflo?

HISAT2, STAR, BWA, and Bowtie2 are all in the GenXflo library. Any of them connect to the Fastp trimmed FASTQ output on the canvas. GenXflo validates the file type compatibility at the connection point before generating any code.

Build Your Fastp Pipeline Today

QC and trimming in one step. JSON output routed to MultiQC. Aligner connected downstream. Reproducible everywhere.