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Head-to-head · Code Duplication Detection Tools

Fallow vs JPlag

  • Updated Oct 2026
  • Both researched from official sources
  • 6 checks side by side
Higher score Fallow #4 in Code Duplication Detection Tools 6.9/10 Free plan · 30-day trial Free planFree trial✓ 3 of 4 features Visit Fallow
JPlag #6 in Code Duplication Detection Tools 6.7/10 Free plan Free plan✓ 2 of 4 features Visit JPlag

Fallow leads on 1 check, JPlag on 1, and 4 are even. Who comes out ahead on the 6 yes/no, price and count checks where we have data for both products. The editor score weighs everything else too.

Our verdict

  • Highest scoreFallow · 6.9/10
  • Free planboth
  • Free trialonly Fallow
  • Most featuresFallow · 3 of 4

Fallow scores higher on our rubric for code duplication detection tools: 6.9 against 6.7 out of 10; our editors rank them #4 and #6.

JPlag leads on supported languages: 20 versus 2. On ci/pr reporting, Fallow gives you Pull_request where JPlag offers None. Fallow offers duplication gates; JPlag doesn't.

Fallow is the better fit for small teams enforcing duplication gates in CI. JPlag is the better fit for academic or multi-language similarity analysis.

  • Fallow fits best

    Small teams enforcing duplication gates in CI

  • JPlag fits best

    Academic or multi-language similarity analysis

Advertiser disclosure: iTechGuides is reader-supported. Vendors can pay for top positions in our rankings and for a place on other products' pages, and we may earn a commission when you click some links. Bought places stand at the number bought; this page and our disclosure say so. Paying vendors may get a fuller, more detailed review from our editors, and that review can change their score. How we rank.

Side by side

Feature Fallow 6.9/10 Visit ↗ JPlag 6.7/10 Visit ↗
At a glance
Editor score 6.9 6.7
Ranking #4 in Code Duplication Detection Tools #6 in Code Duplication Detection Tools
Best for Small teams enforcing duplication gates in CI Academic or multi-language similarity analysis
Pricing model Free plan + paid Free
Starting price $20/seat/mo Free plan
Free plan ✓ ✓
Free trial 30 days —
Deployment Cloud, Self-hosted, Browser extension Self-hosted
Platforms Web, Windows, macOS, Linux Windows, macOS, Linux
Support Email, Community, Docs Community
Integrations 4 integrations 1 integrations
Built for Solo, Small business, Mid-market, Enterprise Small business, Mid-market, Enterprise
Features Fallow 3/4 · JPlag 2/4
Near-duplicate detection ✓ ✓
Duplication gates ✓ (best) —
Trend visualisation Not checked yet —
Open-source option ✓ ✓
Specs
Supported languages 2 20 (best)
CI/PR reporting Pull_request None
Our review
Pros
  • Free MIT scan runs in the terminal, CI, VS Code, and coding agents
  • Baseline and changed-since analysis can focus CI checks on new duplication
  • Multiple detection modes, near-miss analysis, and CI output formats
  • Syntax-aware matching across 20 supported languages
  • Handles some obfuscation and code modifications
  • Free, open source, with CLI and Java API access
Cons
  • Analysis is limited to TypeScript and JavaScript projects
  • Near-miss detection is limited to function-scoped clones with small structural edits
  • Production function-call data requires the separate paid Runtime service
  • Focused on pairwise analysis rather than duplication gates
  • No CI pull-request reporting or trend visualisation
  • Self-hosted setup relies on community support
Our verdict

Fallow is a codebase analysis tool for TypeScript and JavaScript projects, suited to developers and teams who want duplication checks in their everyday workflow or CI. Its free MIT scan detects duplicated code alongside dead code,…

Read the review →

JPlag is a free, open-source tool that compares programs pairwise to identify source-code similarity. It is primarily suited to programming education, where instructors review student submissions, and it can also help examine duplicated…

Read the review →
  1. FallowCode Duplication Detection Tools 6.9Free plan · 30-day trial
  2. JPlagCode Duplication Detection Tools 6.7Free plan

Strengths and trade-offs

  • Fallow — where it wins

    • Free MIT scan runs in the terminal, CI, VS Code, and coding agents
    • Baseline and changed-since analysis can focus CI checks on new duplication
    • Multiple detection modes, near-miss analysis, and CI output formats

    Where it doesn't

    • Analysis is limited to TypeScript and JavaScript projects
    • Near-miss detection is limited to function-scoped clones with small structural edits
    • Production function-call data requires the separate paid Runtime service

  • JPlag — where it wins

    • Syntax-aware matching across 20 supported languages
    • Handles some obfuscation and code modifications
    • Free, open source, with CLI and Java API access

    Where it doesn't

    • Focused on pairwise analysis rather than duplication gates
    • No CI pull-request reporting or trend visualisation
    • Self-hosted setup relies on community support
  • Fallow6.9/10 · Free plan · 30-day trial

    A free TypeScript and JavaScript duplication scanner with CI gates and optional paid runtime insights.

    Visit FallowFull verdict →
  • JPlag6.7/10 · Free plan

    A free, syntax-aware tool for pairwise program-similarity analysis across 20 languages.

    Visit JPlagFull verdict →

More comparisons

All code duplication detection tools comparisons → · Full ranking →

Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

Last updated · How we research and update