​

Finic Selector Service

Selectors are the most import, yet least reliable part of any web automation, which is why it’s what developers spend the most time fixing. Fixing them can also be frustrating as selectors can break at any time with no warning, due to factors completely outside your control.

​

The bad way to manage selectors

Most web automation developers will start by hard coding selectors in their code, like this:

button = page.query_selector("//ul[contains(@class, 'pagehead-actions')]/li/a[@id='fork-button']")

This works fine in testing, but is a headache to update in production when selectors break. A single broken selector requires a code change, PR reviews, and deployment cycle.

​

The better way to manage selectors

The next improvement is to offload selector management to a database, and retrieve it at runtime. This approach is better - at least now broken selectors can be updated with a SQL query instead of a code change.

However this doesn’t actually save the developer much time - they still have to figure out which selectors are broken, then go back to the website and generate new selectors to replace them.

​

The best way to manage selectors

Finic Selector Service is an improvement over this process by fully managing the selector lifecycle on your behalf. It notifies you when selectors break and can even fix them automatically without developer intervention or code changes.

from finic import FinicSelectorService, SelectorError

page = browser.new_page()
fss = FinicSelectorService(api_key=<your-finic-api-key>, page=page)

button = page.query_selector(fss.get("fork-button", regenerate=True))

If the regenerate flag is set, FSS will first attempt to locate the element with the stored selector. If it isn’t found, it will locate the selector in a cached version of the page from the last successful run, then traverse through the tree until it finds a common parent that still exists in the new page. It will then call an LLM with this context to generate a new selector.

Our goal for the FSS is to transform selector management from one of the most time consuming aspects of web automation development into a total non-issue for developers.