NSubstitute

● Identity checked

Developer tools · Vendor site 2026-10-04

NSubstitute is an open-source .NET mocking library focused on Arrange-Act-Assert tests with readable syntax for stubs, spies, and substitutes. The official docs explain how to configure return values and assert received calls without heavy lambda noise compared with older mocking frameworks.

Updated 2026-10-04View sources

Official website

Category: Developer tools
Free access: NSubstitute is free open-source software distributed via GitHub and the project documentation site.
API access: Not confirmed

Is NSubstitute right for you?

A good fit for

.NET developers who want concise test doubles for unit tests without verbose mock setup boilerplate.

Before you choose

You reference the NuGet package in your own test projects; there is no hosted cloud service or vendor support portal on the docs homepage.

Friendly .NET test doubles

NSubstitute focuses on readable substitution APIs so .NET teams can keep unit tests focused on behavior instead of intricate mock configuration.

What it can do

Features & capabilities

Unknown is different from unavailable. Each fact carries its own evidence.

Capability	Value	Evidence	Checked
Testing style	Homepage promotes Arrange-Act-Assert workflows with substitutes for required types.	Facts sourced	2026-10-04
Syntax goal	Docs emphasize natural-language configuration to reduce mock setup noise.	Facts sourced	2026-10-04
Audience	Copy targets newcomers to testing and teams wanting faster test authoring.	Facts sourced	2026-10-04

Understand the total cost

NSubstitute pricing & plans

Free

NSubstitute is free open-source software distributed via GitHub and the project documentation site.

Access: NSubstitute is free open-source software distributed via GitHub and the project documentation site.

Explore pricing & history

Alternatives to NSubstitute

View all ↗

ChartDB

ChartDB visualizes and edits database schema diagrams from a single introspection query without direct database credentials on charting clients. It offers cloud and self-hosted editors, AI-assisted diagram generation, collaboration, exports, and sync with live databases.

Explore tool

Authgear

Authgear is an open-source customer and workforce identity platform from Skymakers. It delivers passkeys, passwordless OTP, SAML SSO, adaptive MFA, RBAC, and user management on Authgear Cloud, customer VPC, or self-hosted deployments with data sovereignty options.

Explore tool

8base.com

8base is an AI-first low-code platform for turning ideas into production web applications. It combines backend-as-a-service with GraphQL APIs, serverless functions, and an app builder so teams can design, build, and run full-stack projects on AWS infrastructure.

Explore tool

The practical questions

Frequently asked questions

What is NSubstitute used for?

Does NSubstitute have a free plan?

NSubstitute is free open-source software distributed via GitHub and the project documentation site.. This record lists ongoing free access; check the plan limits before starting.

How much does NSubstitute cost?

No paid monthly price is listed; this record treats the product as free to start. See the plan cards for entitlements, billing commitments and seat minimums.

Can I use NSubstitute through an API?

Not confirmed. API access and subscription access may have different terms; consult the linked sources.

What should I check before choosing it?

You reference the NuGet package in your own test projects; there is no hosted cloud service or vendor support portal on the docs homepage.

Price history

No retained pricing changes yet. A current price alone does not establish a historical trend.

How this profile is supported

Identity and profile

Reviewed vendor source

Read original source ↗

2026-10-04

Facts apply to the named version and check date. Send a sourced correction if something changed.