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Duplicate transactions

Sometimes the Firefly III Data Importer (FIDI) will create duplicate transactions, despite being told not to. This is pretty annoying so please open a ticket when this happens and let me know why Firefly III didn't detect a duplicate. I can use this information to fine-tune the duplication process.

Deleted, but duplicate?

Firefly III will also check deleted transactions when checking for duplicates. This is on purpose. If your import contains bad transactions or informative message hidden as transactions, they will not be re-imported after you've deleted them.

Futher debugging

Use the debug view to see why a transaction is imported, despite being a duplicate of another transaction. Remember that rules don't influence the (de)duplication process, because rules are applied after the duplication check.

Open both transactions in different tabs of your browser. Notice how the URL is something like this:

Change the word show in the URL to debug:

If you do this for both transactions you will end up with a specific JSON variant of the transaction.

Send it to me or compare it yourself to see the differences between two seemingly equal transactions.

  • The created_at and updated_at fields are not used in the comparison by Firefly III.
  • The import_hash_v2 and original_source are not used in the comparison by Firefly III.
  • The id and transaction_journal_id fields are not used in the comparison by Firefly III.

Common causes

Some common causes of duplicate issues are listed below.

Rounding errors

Some imports contain "floating numbers", which are numbers that look like this:

  • 12.00000001
  • 6.95999999

These numbers may have slight variations. Firefly III will see the difference and create what seems to be a duplicate transaction. The user interface may not show you the trailing digits leading you finding a duplicate transaction.

Different internal or external ID's

Hidden deep in the JSON comparisons you may find a field called external_id or internal_reference. These fields will sometimes be different. Spectre is known to change these sometimes.

Other issues?

Please open a ticket on GitHub.

Last update: 2022-09-24