Hypothesis vs PropEr

Hypothesis9.3Visit PPropEr8.7Visit

Higher score Hypothesis #2 in Property-Based Testing Tools 9.3/10 Free plan Free plan✓ 3 of 3 features Visit Hypothesis

vs

P PropEr #7 in Property-Based Testing Tools 8.7/10 Free plan Free plan✓ 2 of 3 features Visit PropEr

• Hypothesis fits best

  Python teams using pytest

• PropEr fits best

  Erlang teams testing stateful systems

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Side by side

Feature	Hypothesis 9.3/10 Visit ↗	PPropEr 8.7/10 Visit ↗
At a glance
Editor score	9.3	8.7
Ranking	#2 in Property-Based Testing Tools	#7 in Property-Based Testing Tools
Best for	Python teams using pytest	Erlang teams testing stateful systems
Pricing model	Free	Free
Starting price	Free plan	Free plan
Free plan	✓	✓
Free trial	—	—
Deployment	Desktop	Self-hosted
Support	Docs, Community	Community
Integrations	2 integrations	2 integrations
Built for	Solo, Small business, Mid-market, Enterprise	Solo, Small business, Mid-market, Enterprise
Features Hypothesis 3/3 · PropEr 2/3
Failing-case shrinking	✓	✓
Stateful testing	✓	✓
Reproducible failures	✓ (best)	Not checked yet
Specs
Supported languages	Python	Erlang
Test runner support	pytest, unittest	EUnit, Common Test
Cases per run	Not checked yet	Not checked yet
Our review
Pros	Generates edge cases and automatically shrinks failing inputs Supports rule-based stateful testing and failure replay Works with both pytest and unittest across Windows, macOS, and Linux	Generates inputs from PropEr types and native Erlang types Tests stateful systems with generated command sequences Attempts to shrink failures and supports targeted testing
Cons	Supports Python rather than multiple programming languages Requires pytest or unittest instead of providing a standalone test runner Property-based tests require teams to define strategies and properties	Supports Erlang rather than a range of programming languages Requires a self-hosted deployment Support is community-based
Our verdict	Hypothesis is an open-source Python library for property-based testing. Developers define input strategies and properties, then it generates test cases to explore how code behaves, including unusual edge cases. It is aimed at Python teams… Read the review →	PropEr is an open-source property-based testing tool for developers writing Erlang programs. Rather than checking only hand-picked examples, teams define properties and input types, then generate inputs to check whether those properties… Read the review →

Strengths and trade-offs

• Hypothesis — where it wins

  • Generates edge cases and automatically shrinks failing inputs
  • Supports rule-based stateful testing and failure replay
  • Works with both pytest and unittest across Windows, macOS, and Linux

  Where it doesn't

  • Supports Python rather than multiple programming languages
  • Requires pytest or unittest instead of providing a standalone test runner
  • Property-based tests require teams to define strategies and properties

• PropEr — where it wins

  • Generates inputs from PropEr types and native Erlang types
  • Tests stateful systems with generated command sequences
  • Attempts to shrink failures and supports targeted testing

  Where it doesn't

  • Supports Erlang rather than a range of programming languages
  • Requires a self-hosted deployment
  • Support is community-based

• Hypothesis9.3/10 · Free plan

  A focused Python library for generated inputs, shrinking, and stateful tests.

  Visit HypothesisFull verdict →
• PPropEr8.7/10 · Free plan

  A focused Erlang tool for generated properties, stateful models, and smaller failure cases.

  Visit PropErFull verdict →