Become a Supporter

Help us make Thunderbird better.

MZLA Corporation is the for-profit organization sustaining the free software mission of Thunderbird. Our work is to provide open source apps that are secure, private and available for users around the world. When you donate you help us:

  • Develop new apps, integrations and features
  • Improve the interface, speed, and stability
  • Promote Thunderbird and software freedom
  • Serve millions of free app downloads each year

Modify an existing monthly donation.

Become a Corporate Supporter

Secure an open future for yourself and the world.

Organizations deploying Thunderbird at scale or who share our passion for expanding digital freedoms can make a difference by becoming a one-time or recurring corporate supporter. Small to medium size contributions can be made with the form above. For donations greater than $5000 USD please contact our business team. Thank you in advance for your generous support!

A rocket with the Thunderbird logo.

Frequently Asked Questions

What are the ways I can give?

You can donate online securely by credit card or PayPal. Google Pay, Apple Pay, and bank transfers through SEPA, iDEAL and ACH are also available online.
Give in your local currency! On our online form, use the drop down menu next to the amount. You will be charged in the currency you choose to give with.
Additionally you can give offline in USD by mailing a check or money order made payable to "MZLA Technologies Corp". Mail to:

  • MZLA
  • PO Box 25718
  • Pasadena CA 91185-5718

Please include your email address on the memo line of your check to help us track and attribute your gift.

Give the gift of your time! If you would like to learn how to contribute to Thunderbird in other ways such as coding, translating or testing, please visit our Participate page.

How do I cancel or change my recurring gift? Can I change my payment method or my donation frequency?

Access your donation account settings using the 'Manage My Donation' button on your recent donation confirmation email. There you can change the amount, frequency, payment method and charge date. You can also cancel your recurring donation plan. If you run into any issues you can always contact us!

Why do you need my address in order to process a gift?

We understand that your privacy is very important -- we agree, and that's a core value of ours at Thunderbird and Mozilla. Your address is part of our Payment Processing, Contact and Donation Information that we outline in our Privacy Policy. This data is used for payment processing, transactional receipts, fraud detection and record-keeping purposes. If you want to know more about the personal information data we receive, the third-party vendors we trust, and how long we keep your data, please refer to our Websites, Communications & Cookies Privacy Notice.

Does my gift give me access to tech support?

Anyone can access tech support for Thunderbird by visiting the support forum. Thunderbird does not provide tech support or enhanced tech support in exchange for financial gifts.

How can I turn off the donation message on the Thunderbird start page?

To learn how to customize your start page please visit:

Is my gift tax deductible?

Gifts to Thunderbird are not tax-deductible as charitable gifts, but are greatly appreciated. Giving to Thunderbird supports the development of our leading open source cross-platform email and calendaring client, free for business and personal use. Your gift will help ensure it stays that way, and will support future development.

How can I get a business receipt?

When you donate via our online form, simply check the box 'Donate as an Organization' and include your company name. The receipt you receive to the email address used to make your contribution will include your business information.

Is my donation secure?

Yes, we use industry-standard SSL technology to keep your information secure. We partner with Stripe, the industry's established payment processor trusted by some of the world's largest companies. Your sensitive financial information never touches our servers. We send all data directly to Stripe's PCI-compliant servers through SSL. We understand that your privacy is very important. For complete information please refer to the Mozilla Privacy Policy.

Can I request a refund?

Your donation may be eligible for a refund. You must contact us within 15 days after the date of the donation. If you believe this donation was made without your authorization, please contact us immediately. Donations made via ACH or SEPA direct debit are ineligible for refunds. Due to the nature of these transactions our policy prioritizes minimizing refund fraud. We sincerely appreciate your understanding. If you have any further questions, please contact us.

Are there additional fees on my donation?

We do not collect any additional fees or taxes. When you donate in your local currency you are not charged a conversion fee by your credit card. Optionally, you can choose to cover our transaction costs on your donation. This is completely voluntary and you may opt in or out using the checkbox on our donation form. Our organization is based in the United States. We encourage donors to research any additional external taxes or fees that may be applied by regulators such as your bank or tax authority.

What are your transaction costs on donations?

When you opt to cover our transaction costs, you're covering both our processing and donation platform costs. The costs associated with our robust online donation system allows us to continue scaling sustainably as our supporter-base grows. Our donation platform and payment processor partners reduce internal costs associated with maintaining our own system from scratch. Our partners ensure we can accept a wide range of currencies/payment methods and remain PCI compliant in all of the countries that we accept gifts from. The transaction costs donors may choose to cover are based on an estimate of our overall costs. Due to many factors actual costs may fluctuate.

Why do one-time donations appear as recurring in the SEPA mandates?

When making a one-time gift through SEPA direct debit, you may notice a mention of recurrent transactions. This is because our payment processor Stripe only supports recurring transactions for this type of payment. Regardless of this, we will only charge you once and we will not make any further payments on your account without your authorization. Following the mandate, you will receive an official donation receipt that will clearly reflect the one-time donation.

Can I give in cryptocurrencies?

No. We are not currently accepting cryptocurrency gifts.

How will my gift be used?

Thunderbird is the leading open source cross-platform email and calendaring client, free for business and personal use. Your gift will help ensure it stays that way, and will support future development.

What is Thunderbird’s relationship to MZLA Technologies Corporation?

Thunderbird is a project of MZLA Technologies Corporation, which is a wholly owned subsidiary of Mozilla Foundation.

Doesn’t Thunderbird earn income?

Currently, the majority of Thunderbird’s revenue comes from generous gifts from users and friends of Thunderbird. Companies and individuals support the development of the product now and in the future.

Contact us

If you have a question about giving to Thunderbird, please contact us via this form. If you need technical support, please head over to Thunderbird Support for assistance.

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