Instant help with common issues

Subscription isn't active

It might happen that a subscription wasn’t activated automatically or you have bought it with a different Billdu account.

Send us a your bill, invoice or screenshot to our e-mail address

Also state the e-mail address you use to log into your Billdu account.

We will activate it for you right away!


You can also read more about our subscriptions and how it works in the section Pricing and subscription of this guide.

Unable to log in

Please pay attention to the error message – you may got the password or e-mail address wrong. If you don’t remember your password you can always create a new one. Click on I forgot my password on the login screen or click here and follow the instructions. A message will be sent to your email and you will be able to set a new password.

Please pay attention to the error message – you have probably typed your password or e-mail address wrong. If you don’t remember your password you can always create a new one on our website. Just click on I forgot my password on the login screen or click here and follow the instructions. A message will be sent to your e-mail address and you will be able to set a new password.

If the app doesn’t recognize the password after a password change then a re-installation helps in most cases. You can also contact our technical support at for more details.

Invoices suddenly disappeared

Your date filter is probably set to This year. Change the time-frame and you will see more of your documents.

Also check your fiscal year start. It may be set to a date span that does not include the current date. Check the settings at Settings Document settings Tax years begins


The date filter is in the upper row in your invoice list and says This year or This month. Change the filter to a wider time range to see all your invoices (Lifetime).


Tap on This year – it’s the most upper text when you take look onto your invoice list.

A menu appears where you can select more time ranges

Tap on Last year or Lifetime


Recover deleted invoices

Currently it’s not possible for a user to recover a deleted invoice. Send us an e-mail to with the exact invoice number or the time-frame you wish to have your invoices recovered and our technical magicians will do it’s to best bring your documents back to life.

“You have reached the max. number of documents”

Your subscription is still valid but you have already created the maximum number of documents (invoices, estimates, orders,…). You can still edit, send and delete your documents but to create new documents you need a new subscription.
If you see this message often, you may want to consider a change to a higher subscription plan.

“This feature is available with a higher subscription"

Certain features and document types are available only for certain subscriptions plans. Take a look at our price list for a better overview of features and subscriptions.

"Max. Number of Mobile Devices exceeded."

For every subscription there is a specific number of mobile devices you can use with your account. If this message appears you have either a subscription with a low device number or you need to manage your device list.
In some cases (mostly after app reinstallation or an update) Billdu assumes your device is new. Log into the Billdu website and navigate to Settings – Mobile devices. You can see all your mobile devices in there. Delete the mobile device and now you will be able to log in to the mobile app again.

"We strongly recommend to update your Billdu version in AppStore."

This message appears when you use a quite old version of Billdu. Some new features are available only with newer versions of Billdu, also the stability of data synchronization is improved with every app version. If you use a deprecated version (v4.1.10 an older) this error message might appear and we strongly suggest to update your application in App Store. You may also want to check on the Billdu website if all your data has been synchronized correctly.

Billdu iOS app needs iOS 10 or higher in order to work correctly. Older operation systems such as iOS 9 or 9.3.5 are not supported. However you might be able to download an older version of Billdu from App Store (if supported by Apple).

Invoices note sent or delivered

If you’ve sent an e-mail from your mobile app and it hasn’t been delivered, you may want to check the settings of your native mail app. Also check the Sent items in your native iOS Mail app – if the invoice is in there, it has been sent.

It may happen that an e-mail lands in client’s SPAM folder or it has been filtered due to high security settings of client’s mail app – this is something you or us have no control about.

There are more ways how to send emails, take a look here to learn more about it.

Delete a Billdu account

Send us an email from the e-mail address you used to register your Billdu account to and we will delete your account. A confirmation message will follow shortly.

No change to an invoice after editing Business details

A change of your business’s details can’t alter your invoices retrospectively, that would create quite a mess in your documents.

If you need to change your business details on a specific invoice, edit the invoice on the Billdu website and select on Edit company details. A window will appear where you can edit all your company details for that specific invoice.
If you’ve added a logo or signature to your Business settings, it will show up on the first invoice you create AFTER such change. In case you need a logo to show up on your invoice, upload a logo to your business settings first and create a new invoice (you can also use the duplication feature)

No change to an invoice after editing Client details

Changing client details shouldn’t change your invoices retrospectively, that would create quite a mess in your documents.
If you need to change client’s details on an invoice, proceed as follows:

  • Edit the Client and change it’s details
  • Edit the invoice and select another client (any client will do)
  • Save the invoice
  • Edit the invoice again
  • Select the right client
  • Save again

Now the actual data from the client were refreshed in the invoice and you will see the desired client’s details.
In the mobile iOS app edit the invoice, select the Client – a new window with client’s details appears. Here you can change basic client information directly on an invoice however this has no effect on the client, it just updates the invoice.

Add a negative tax (CIS)

Edit the tax rate in Settings – Document settings and enter a negative tax.

Now create an invoice and select the negative tax from the drop-down list.

Create invoices offline

You can create invoices, estimates and other documents even offline with our mobile apps. Your documents will not receive automatic numbering. The numbers will be added later when connected to the internet and after a synchronization.

Using more mobile devices or computers

You’re welcome to use your Billdu account on any computer, just log in on the Billdu website with your e-mail and password you’ve used to sign up into the mobile app (or vice versa). All your data will be synchronized. You can manage your account with the mobile app and from the website as well.

You can use Billdu with more mobile devices but the number of available mobile devices depends on your subscription. Check our price list to see how many mobile devices you can use with one Billdu account.

App reinstalation or deletion

All your data is stored on our secured cloud-based server. If you delete the app from your mobile device and log in again with your e-mail and password, your invoices and all other data will show up.

Just make sure – before reinstalling the app – to check if all your data and documents are saved on the Billdu website. Visit our Billdu website and make sure all your invoices, clients, etc are correctly saved. You can freely delete and install the app again afterwards.

Billdu currently doesn’t support a log-out from the app.

Invoice attachments

Create a document and click on the paperclip icon in the upper right corner
Take a picture or select an image from gallery, add Name and Description and press Done
If a message appears to allow Billdu access your device, click OK
Images will be added to your invoice and you can see it in the preview

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Billdu sends several kinds of e-mail messages

Welcome messages introduce the Billdu tool and inform you about app’s features
Our Newsletter and promotional e-mails inform you about news, updates and current promotions
Infomails are sent occasionally to inform you about a specific event, feature or changes

You can either click on Unsubscribe at the bottom of the e-mail message or send us a reply to