Add support for HAR file replay for network mocking (routeFromHAR)

[eslamelmishtawy]

Is your feature request related to a problem?
I need to mock API responses for testing but Robot Framework Browser only supports recording HAR files, not replaying them. Currently, I can record network traffic with recordHar in New Context, but there's no way to use that HAR file to mock responses in subsequent test runs.

This means I cannot:

• Test applications offline with previously recorded traffic
• Create reproducible tests with consistent API responses
• Mock backend APIs while testing frontend independently

Describe the solution you'd like
Expose Playwright's routeFromHAR() functionality through new Robot Framework keywords. Playwright already supports this - it just needs to be exposed.

Proposed Keywords

2. Route Context From HAR (context-level)

Route Context From HAR
    [Arguments]    path    url=${NONE}    update=${False}    notFound=abort

Example Usage

*** Test Cases ***
# Step 1: Record HAR (first run)
Record API Traffic
    ${har} =    Create Dictionary    path=./api.har
    New Context    recordHar=${har}
    New Page    https://example.com
    Click    text=Load Data
    # Network traffic recorded

# Step 2: Replay HAR (subsequent runs)
Test With Mocked Data
    New Context
    Route Context From HAR    path=./api.har    url=**/api/**
    New Page    https://example.com
    Click    text=Load Data
    # Requests to /api/** served from HAR file (offline, fast, consistent)

Additional context

• Playwright Documentation: https://playwright.dev/docs/mock#replaying-from-har
• Playwright API:
  • page.routeFromHAR()
  • browserContext.routeFromHAR()

[Siddhartha-singh01]

@eslamelmishtawy If it is possible then assign it to me

[aaltat]

@allcontributors please add @eslamelmishtawy for ideas. @eslamelmishtawy there are two ways to implement this one, on context or page level, which way you would like to see this one to work? Or perhaps both ways are good ideas?

@Siddhartha-singh01 if you want create a PR to implement this one, please go ahead, the issue is yours. Do you need help on something or is it clear how to do this enhancement.

At least we should discuss about the keyword argument syntax and decide about the level where har is attached, page or context.

[allcontributors]

@aaltat

I've put up a pull request to add @eslamelmishtawy! 🎉

[eslamelmishtawy]

If possible adding both on page and context level would be great @aaltat

[aaltat]

We can have a single keyword which can handle both cases. Have you given any thought about the keyword name and arguments?

[eslamelmishtawy]

Will the example provided above work?
I was thinking of two keywords Route Context From HAR Route Page From HAR
If we want to unify it we can Route From HAR {har_file_path} {scope} {url_filter} => urls to filter {update} => whether to update file with missing requests or not

[aaltat]

Underlying Playwright API has plenty of options https://playwright.dev/docs/api/class-page#page-route-from-har and it would be nice to support them all

[rasjani]

https://github.com/MarketSquare/robotframework-browser-extensions/blob/main/mockUrl/mockUrl.js#L82 - has mocking from har and i've used it when testing "big ecom site" during 2025 with my previous customer so "it should work".