Diffblue vs Refraction (2026): Pricing, Features & Which to Choose

Who comes out ahead

Based only on the facts in our directory. The right pick still depends on the job you need done.

Lower starting price
Not comparable
Not comparable: Refraction does not list a price
Free plan
Refraction
Only Refraction has one
Higher rating
Diffblue
4.0 against 3.9
Same job?
Yes
Both are Coding tools

Side by side

Compared on	Diffblue	Refraction
Our rating	4.0Better	3.9
Starts at	$1,500/mo	Free
Free plan	No	YesBetter
Category	Coding	Coding
Plans	From $1,500/mo	Free
Key features	Autonomously generates unit tests across an entire repository Every test is verified to compile, pass and add real coverage before billing Extends existing AI platforms like GitHub Copilot CLI and Claude Code Billed only for net new coverage, independently verifiable with standard tools Supports Java 8 through 25 and Python 3.9 and later	Unit test generation from pasted code Refactoring suggestions and code explanations Documentation generation for existing functions Browser-based with no editor extension required
Pros	Pricing is tied to verified results, not seats or API calls Billing can be independently confirmed with a team's own coverage tool Named enterprise customers across finance and technology	Targets the work that actually gets skipped under deadline No setup, so it is usable on any codebase immediately
Cons	A passing, coverage-adding test still needs review for whether it checks anything meaningful Understanding the baseline measurement matters before estimating actual cost Currently limited to Java and Python codebases	Generated tests can assert the wrong behaviour if accepted unread Browser paste workflow is clumsier than an in-editor assistant
Company	Diffblue Ltd., founded 2016

Prices come from each vendor's pricing page, last checked 20260923. Check the vendor before you buy.

FAQ

Questions people ask

Is Diffblue better than Refraction?

In our reviews Diffblue scores 4.0 and Refraction scores 3.9. The better pick depends on the job. Diffblue: AI unit-test generation agent from Diffblue Ltd. that writes verified, coverage-adding tests for Java and Python codebases, billed only for coverage delivered. Refraction: Generates unit tests, refactors and documentation from code you paste in.

Which is cheaper, Diffblue or Refraction?

Diffblue: from $1,500/mo. Refraction: free.

Do Diffblue and Refraction have free plans?

Only Refraction has a free plan.

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Refraction compared with

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