Mockfly

Mockfly is a hosted mock-API workspace for engineers who need shared endpoints before production services exist. It fits teams that want imports, conditional behavior, automation and local offline serving in one workflow. The main trade-off is capacity: the free tier is suitable for a small proof of concept, while sustained team use requires a paid plan.

Overview

Mockfly creates mock REST endpoints with several possible responses. Conditional rules select a response from the incoming request, allowing one endpoint to represent success, error and state-specific paths instead of returning a single fixture. Responses can be JSON, XML, or files such as PDF and CSV, so it can model clients that consume more than JSON.

Faker.js templates and AI-generated JSON produce sample payloads without hand-authoring every value. OpenAPI, Swagger, Postman collections and HAR captures can be imported, reducing setup when an interface already exists. The Chrome extension captures browser requests and adds chosen endpoints to a project, useful when a real user flow is the starting point.

Key features

Teams can share and edit mocks, inspect request logs and review response-body history. That makes the service a shared testing asset rather than a disposable local stub. A public REST API and MCP server let automation create and modify mocks programmatically, which suits CI or internal tooling workflows.

The mockfly-cli npm package pulls projects and serves them locally without an internet connection. This provides an offline path for development and testing, while the hosted service remains the collaboration hub. Mockfly supports REST and WebSocket protocols. Its stated data practice is to store mock definitions and project request logs to operate the service, not sell that data, and it says it does not set tracking cookies. Direct support is offered by email in English or Spanish.

Pricing

Starter — free (billed 0€ per month) is a constrained evaluation tier: 500 requests per day, one project, four endpoints and two responses per endpoint. Those ceilings can work for a demo or a single small feature, but they leave little room for several concurrent client flows.

Pro — €15 a month (billed 15€ per month) removes request, project, endpoint and per-endpoint response limits. It adds a custom domain, AI generation and support, making it the practical baseline for an individual or small project that has outgrown Starter.

Team — €49 a month (billed 49€ per month) includes everything in Pro, five seats and priority support. Extra seats cost 9€ a month each. This is the clearest fit for a small group that needs shared editing and defined user access.

Company — from €199 a month (billed From 199€ per month) includes Team features plus setup assistance and custom seats, integrations and SLA. It is aimed at organizations needing a tailored commercial arrangement rather than a fixed self-serve package.

Platforms

Mockfly is offered through web, API and extension interfaces, with Linux and self-hosted options. The CLI enables local serving without an internet connection, while hosted projects support browser-based collaboration.

Who it's for

Frontend, backend, mobile, QA and testing engineers can use Mockfly to unblock client work before a backend is ready. It is especially appropriate for teams importing existing API descriptions, modeling request-dependent behavior, or keeping mocks synchronized through scripts and MCP tooling. A solo developer with only a few endpoints may find Starter adequate; larger shared projects will quickly need Pro or Team. If your priority is a permanently local, open-source mock server with no hosted workspace, Mockfly is less aligned with that requirement.

Pros and cons

Pros

• Conditional multi-response endpoints model varied request states and error paths.
• OpenAPI, Swagger, Postman and HAR imports shorten migration from existing definitions.
• JSON, XML, PDF and CSV responses cover more client scenarios than JSON-only fixtures.
• CLI-based offline serving, REST API and MCP support both local work and automation.
• Shared editing, logs and response history support team review.

Cons

• Starter is limited to 500 requests per day, one project, four endpoints and two responses per endpoint.
• Team collaboration costs €49 per month for five seats before extra-seat charges.
• Hosted operation requires storing mock definitions and request logs with the service.

Alternatives

Browse the broader API Mocking Tools list when you want to compare the category. Choose Microcks instead if a 100% open-source, community-driven CNCF Incubating project and broad self-hosted platform coverage matter most.

Mockzilla is a better fit when a low-cost plan with 1,000 requests per month, 5 requests per second and one simulation matches your workload. Beeceptor suits users seeking a $10-per-month Individual plan with 15,000 requests per month per endpoint, private endpoints and persistent CRUD objects.

Pick MockServer for a free, self-hosted open-source server with no SaaS account. Mockttp is aimed at traffic viewing, rewriting, manual breakpoints and a built-in HTTP client. WireMock offers a free tier with 1,000 calls per month, three mock APIs and 10 requests per second.

Knockout API is an option for image-oriented usage with a free 30-images-per-month plan. MockAPI costs $5 per month for 20 projects and 50 resources, making it preferable when simple project/resource quotas are the deciding factor.

Verdict

Choose Mockfly if you need shared, importable mocks with conditional responses, automation hooks and an offline local fallback. Its strongest advantage is the breadth of one workflow, from browser capture and API imports to team history and scripted editing. Look elsewhere if you require an entirely open-source self-hosted product or if the Starter limits cannot accommodate your request volume and endpoint count.