PrimerForge
Open · Free · Bring-your-own-key

Design PCR primers that only amplify your species.

Enter a target species, pick what it shouldn't react with, and get ranked primer pairs — vetted by an AI expert. No account, no cost, just your OpenAI key.

Uses NCBI GenBank · BioPython · 100% client-side API keys.

Experiment #402
2026-06-21
Seq 1ATGCCATGAACTG
Seq 2ATGCTATGAACTG
Primer pair A selected

Engineered for precision

Sequence harvest

Auto-fetches the longest coding region from NCBI GenBank by species and gene — or discovers a marker gene when you leave it blank.

Specificity at the 3' end

Enforces at least two mismatches in the final 5 bases — the exact region where Taq polymerase first fails — so cross-reactions stop before extension.

AI-graded candidates

An AI expert assigns an A / B / C grade and biological rationale to each pair. Template fallback works without a key.

Lab protocol

  1. 1. Sequence Search

    Specify your species

    Choose your target organism and what it needs to be distinguished from. Leave the gene blank to let PrimerForge auto-detect a marker gene based on the target's taxonomic group.

  2. 2. MSA Alignment

    Alignment results

    Multiple-sequence alignment with species-specific regions highlighted.

  3. 3. Primer Design

    Primer candidates

    Candidate pairs that pass every hard filter, listed by genomic position — a screened set for validation, not a ranking.

  4. 4. AI Report

    AI analysis report

    The AI generates a narrative brief covering screening criteria, the candidate set, PCR conditions, and cautions.