@Joshua_Upton already quoted the relevant part of the API documentation, but to give some more context on this, the delay is dependent upon a number of factors such as the size of your doc and Coda’s overall service utilization. Essentially, to support relatively fast lookups on docs, it takes some time for changes to a doc to get saved (“snapshotted”, as we call it internally) into a cache that is then read by the API — this might include something like recalculating an entire doc if, say, a core formula in the doc is changed.
We have discussed an alternative architecture to our API that would support realtime updates, but it would be a lot of work and possibly be prohibitively expensive for us to offer. A change we’re more likely to make shorter term is to have the update be blocking, or a return a URL you can ping that will tell you when your change has been applied.
In the meantime, you can try and get this working yourself by writing the current timestamp into a separate table. You can then poll that value using the API and wait until the timestamp returned by the API is equal to or newer than the value you wrote in, which would indicate that any updates to the API made before that have already been processed.