Knockout API vs Mockfly
Knockout API
useknockout.comMockfly
mockfly.devSide by side
| Figure | Knockout API | Mockfly |
|---|---|---|
| Price from | $0.02/mo | €12.50/mo |
| Free plan | Yes | Yes |
| Free trial | — | — |
| Open source | — | — |
| Web | Yes | Yes |
| Linux | — | Yes |
| API | Yes | Yes |
| Self-hosted | — | Yes |
| Plans published | 7 | 7 |
| Spec score · API Mocking Tools | 8.4 (#7) | 9.2 (#2) |
| Integrations | Official client options include Node, React, Python, and CLI, alongside REST and any HTTP client. | The Chrome extension captures browser requests and adds selected endpoints to a Mockfly project. |
| Purpose | Knockout provides image and video processing tools through a browser app and API. | Mockfly creates hosted mock REST API endpoints so teams can build and test before a backend is ready. |
| Support | The site lists community support for Free, email support for Pay-as-you-go, and Slack support for Volume. | Support is provided directly by the builders through email, in English or Spanish. |
Plans
Knockout API
- FreeFree
- Pay-as-you-go$0.02 a month
- Knockout Plus$10 a month
- FreeFree
- Pay-as-you-go$0.02 a month
- Knockout Plus$10 a month
- VolumePriced on request
Mockfly
- StarterFree
- StarterFree
- Pro€15 a month
- Team€49 a month
- Pro annual€150 a year
- Company€199 a month
- CompanyPriced on request
In their own words
Knockout API
Knockout API provides image and video processing through a browser app and API. Its image tools cover background removal and replacement, batch processing, masking, smart crop, stickers, outlines, shadows, and inpainting; the API also handles upscaling, portrait restoration, colorization, and object removal. Video background removal runs asynchronously, with job polling for progress. The browser Canvas supports layered designs with text and effects, and users can save canvases and cutouts to a free account. Developers can connect through REST, any HTTP client, or official Node, React, Python, and CLI options. The service says it manages GPU processing, endpoint updates, usage records, credentials, teams, and billing. Its privacy policy says uploaded images are processed in GPU worker memory, not retained after the response, and not used to train models. The Free plan is free, with 30 images per month and 60 requests per minute. Pay-as-you-go is $0.02 a month, with metered usage billed monthly; Plus is $10 a month. Paid tiers have no monthly cap and a 600-request-per-minute limit.
Mockfly
Mockfly provides hosted mock REST API endpoints for teams building or testing before a backend is ready. An endpoint can return JSON, XML, or files such as PDFs and CSVs, and can select among several responses using rules tied to incoming requests. Mock data can use Faker.js templates or AI-generated JSON. Projects can start from OpenAPI, Swagger, Postman collection, or HAR imports; a Chrome extension can capture browser requests and add selected endpoints. Teams can share and edit mocks, inspect request logs, and review response-body history. For offline work, the mockfly-cli npm package pulls projects to serve locally. A public REST API and MCP server support programmatic mock creation and editing. Mockfly lists API, extension, Linux, self-hosted, and web platforms, and supports REST and WebSocket. The free Starter plan allows 500 requests per day, one project, four endpoints, and two responses per endpoint. Pro costs €15 a month; Team costs €49 a month; Company is listed from €199 a month.