Hello and first a note of solidarity to your tech team with the ongoing issues in the API - we appreciate their efforts to resolve things! 
For the reindexed works, will this affect their “deposit-date“ at all, or only their “index-date“. I would like to know what would be the most effective way to retrieve the DOIs of all the works which have been affected by the ongoing indexing problem (once it is resolved).
Many thanks in advance!
An additional question is - for the records that have been reindexed (e.g. from 7th July-14th August) - is it “safe” to slowly begin pulling their metadata?
Hello, and thanks for your questions.
The deposited date and created date will be unaffected by the indexing delay. The indexed date will reflect the date/time the item was eventually indexed, even though that’s days or weeks later than it ought to have been. So, you’ll see a much bigger lag between the created/deposited dates and the indexed date in these cases.
You can definitely retrieve the metadata from the items that were missing and have now been re-pushed for indexing. Is your concern that there might still be missing items that will be reindexed at a later point?
The main point is to be able to discover the DOIs which were previously unindexed - which I think would most easily done by using the from-index-date and until-index-datefilters, as opposed to the (usual) from-deposit-date and from-deposit-date filters (which also works for redeposits in the case of metadata updates)?
Gah - from-deposit-date and until-deposit-datefilters!
Hello @abeechin ,
Yes, you should be able to use the from-index-date and until-index-datefilters to retrieve those records that were missed. For instance, the from-index-date and until-index-datefilters should have a lot more works in them with an index date of 14 August, because we pushed over 1 million records on the 14th that had not been previously indexed from the 3rd to the 13th.
As @Shayn alluded to, we do have a small number of DOIs that are still unindexed, like this one that was originally registered on 8 July: 10.71386/BRFJ.9.1.2025.1-8 . That DOI is in our XML API, but not yet in our REST API:
XML API 
v. REST API 
Warm regards,
Isaac
Excellent, thank you both!
Could you provide a few DOIs which would be in that million which was recently re-indexed? It would help me (and probably others) test whether we have “caught up” so-to-speak
Sorry - another question - during this period of indexing problems, was the OAI endpoint also affected?
Here are a few:
https://api.crossref.org/works/10.36557/2674-8169.2025v7n8p322-337
Looks like the reindex completed on 15 August. Sorry it was the 14th were I am located (and that’s why I said what I did in my previous message). The API uses UTC, so you should use the 15 August in your calls, as you can see above..
-Isaac
Perfect, thank you very much 
Good luck with resolving the indexing issue!
