# Advanced search API for Incorporation Date **URL:** \ **Category:** API Question\ **Created:** [September 25, 2025, 9:56am UTC](http://forum.companieshouse.gov.uk/t/advanced-search-api-for-incorporation-date/12162 "2025-09-25T09:56:57Z")\ **Posts on this page:** 1\ **Showing post:** 2
**Author:** ![voracityemail](http://forum.companieshouse.gov.uk/letter_avatar_proxy/v4/letter/v/b77776/32.png) [@voracityemail](http://forum.companieshouse.gov.uk/u/voracityemail)\ **Post date:** [October 2, 2025, 7:28pm UTC](http://forum.companieshouse.gov.uk/t/advanced-search-api-for-incorporation-date/12162/2 "2025-10-02T19:28:04Z")
(Not from Companies House, just another punter). Depending on exactly what you want to find out, you may be better with [the Streaming API](https://developer-specs.company-information.service.gov.uk/streaming-api/guides/overview). Pros: - You are notified as soon as Companies House has processed an incorporation filing. - You avoid both the rate limit AND the other limits which apply to the Advanced Search - and indeed other parts of the API. Rate limiting is in the [Public Data API](https://developer-specs.company-information.service.gov.uk/companies-house-public-data-api/reference) e.g. for individual queries). What that means is there is a maximum number of records the Advanced Search will return - if more registrations than that came in you simply cannot get the information! See e.g. this thread: > [@/advanced-search/companies responds with 500 after 10000 items](https://forum.companieshouse.gov.uk/t/advanced-search-companies-responds-with-500-after-10000-items/4813/8): > > it’s not an error, I ran into the same issue and now having to rebuild my logic to suit the API The issue here is that your query returns lets say 20,000 results, the API request returns the first 5,000 of the 20,000 and your start\_index is for the 5,000 results that the API returns not for the entire 20,000 matches. You are basically telling the API to order your results from number 10,000 with only 5,000 results returned thus the 500 error. What you should be doing is making sure that your … Cons: You have a continuous process (which needs some code to manage reconnection), rather than “sample once per day”. Of course, you can just stash all the data yourself then you can sample this whenever you like… For how to sign up see the links on the thread below. I believe this covers both the “Public Data API” for making individual queries and the Streaming API. > [@getting an API key](https://forum.companieshouse.gov.uk/t/getting-an-api-key/12120/2): > > Welcome - you asked about API keys but just in case - do you need to access the Companies House Public Data API / Streaming API OR do you want to actually file information? For the latter the process is different. For the Public Data / Streaming APIs you will use an API key. I believe the main Companies House instructions are here: It’s been a long time since we signed up but the instructions here should help: Essentially - go to: … and sign up, then choose “Create an Application”. I… Good luck. --- _[View the full topic](http://forum.companieshouse.gov.uk/t/advanced-search-api-for-incorporation-date/12162)._