Easily create beautiful personalized letters the NXT way!

Stop producing letters and acknowledgments the hard way – use the most popular letter app on the Blackbaud marketplace to make thank you’s, receipts and letters simple, automated, and do it in less time than you thought possible.

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Red Arc apps are trusted by…

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  • Untitled design (3)
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It’s easy to get started creating beautiful personalized letters.

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2 ways to smash your year-end goals this EOFY

1. Check out  3+ Reasons to Use Giving Summaries this EOFY

2. In true Aussie fashion, we’ve got an EOFY offer for you!

Any NEW subscription to Letter Box Premium taken out between now and June 30th will get 15% off the first year’s subscription! *T&C’s apply


  •  Upgrade via the Letter Box app
  • Select the Annual Subscription option
  • Choose your currency 
  • Add the coupon code EOFY15 in the checkout process

*Terms and conditions
Only valid for new annual subscription plan taken out by June 30th 2024.
Sorry doesn’t apply to monthly plans 🙂

We’re excited to announce new features for Letter Box.

New Feature May - Org support (1)

Organizational Contact Support 

 Letter Box can now find the primary contact for an organization and substitute name/salutation fields automatically.

Details on how to start using the new feature here

Scheduled Letters
You can now create a bulk letter run that runs automatically on a schedule. Right now, these can be run daily – think Birthday greetings (🥳) – And very shortly, you’ll be able to do this weekly, monthly or whenever you like!

Pledge Schedule Templates
We’ve also just added a new template type that contains the elements you need to create a pledge schedule showing pledge and instalment details.

Combine the two: automatic sending using Scheduled Letters + Pledge Reminder Templates, and you have Automated Pledge Reminders!


5 star review
  • Makes Email Marketing a breeze!

    Using Campaign Monitor as our Email Marketing Software, we needed something to bridge the gap between RE and CM – the Email Marketing Connector does just that, fully automating all data processes between the two platforms seamlessly!

    The team are incredibly helpful, from onboarding to support, replies are speedy, friendly, and help with any questions we may have.

    Hospice in the Weald
  • Letter Box is superb! Time saver!

    Letterbox is a great product; the letters can be done in bulk and a pdf of the letter is added to each GIFT for that particular donor; you can also do individual letters and save to the record.
    Red Arc is continuing to enhance the product every day – recent additions are summary letters that you can customize. There is a free version that allows for 5 templates – we started with that and saw the value and upgraded to the premium version (it’s a very reasonable expense) and are so very glad we did.
    Thank you Red Arc for an amazing product!
    Texas Women’s Foundation
  • Measure engagement data in just a few clicks. It's that simple!!

    This out-of-the-box product allows you to quickly develop constituent engagement scores in a matter of seconds. Just open the tile, link to a list, add scoring criteria, and boom, you have an engagement tile that measures how engaged your constituents and prospect are. Each individual is given their own score based on the criteria you set. Completely flexible and customizable for any user regardless of skill level. Highly recommend this product.

    St Norbet College
  • Highly recommended for RE NXT!

    Email Marketing Connector has increased efficiencies for my organization, allowing us to build segments and manage email automation through a smooth integration. Our relationship managers especially love the user interface within the Email Activity tile, providing insights into the email marketing activities and email behaviours of our donors. Once set up, the connection was seamless and easy to set and forget. I highly recommend the connector for integrating RENXT with email marketing systems (Campaign Monitor for us)

    Boys and Girls Clubs


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Create one-off letters and acknowledgements directly from a constituent/gift record

  • Create a letter in seconds using one of the templates you’ve designed.

  • Want to add something personal? Optionally open the letter for editing before creating, all built into NXT

  • Letter Box automatically records that you sent the letter and attaches a copy of the PDF

  • Click Create and the letter will download/print or be sent via email (Premium Plan)

You’re done! Back to your other work!!

Create letters in bulk using Bulk Letter Runs

Take the simplicity of creating one-off letters, add an NXT List, and you have Bulk Letter Runs. Organisations use them for regular acknowledgement batches, receipting, or sending communications to a group of constituents.

  • Select a template and an NXT List and you’re ready to go!
  • Edit before sending? Of course!! You or another member of your team can add personal messages to some or all of the letters before you finally click Create. All using the same built-in editor you used to create the template.
  • Once you’re ready, click Create and you’re done. Letter Box will handle creating the PDFs, downloading or directly emailing them (Premium Plan), tracking and recording.

Advanced features
– all built right into NXT

Letter Box is entirely built within NXT – no need for any additional apps. Advanced features including Full featured template editor, Personalizing letters before sending and Receipt Number Generation are available on all plans.

Premium Plan Additions 

Pricing in US$

See here for pricing in AU$ and £ 

Letter Box plan options


Individual Constituent Letters
Individual Gift Letters
Bulk Letters with Receipt Number Generator
eSignatures via DocuSign
Receipt Number Generator
500 Letters / month
5 Templates
Letter Box plan options 1


All of Free Forever
Built-in Email Delivery
Giving Summary Templates
Conditional Templates
Automated Pledge Reminders
Scheduled Letters
Auto Send Letters
2,000 Letters / month
Unlimited Templates
Need more letters? Add Letter Packs


Check out our Knowledge Base for more information on Letter Box Premium.
If you still have a question, please just get in touch; we’d love to help!