[PM-11525] Tax calculation shown to customers potentially incorrect

[jonashendrickx]

🎟️ Tracking

https://bitwarden.atlassian.net/browse/PM-11525

📔 Objective

This value is calculated using our exiting TaxRate records that we store in our own database and are managed via the Bitwarden Admin Portal. However, after we transitioned to using Stripe Tax for automatic tax calculations, there’s a likelihood that this “Estimated tax” value will be incorrect because whatever value we have saved could be different from the value Stripe calculates on the fly for the same zip code.

📸 Screenshots

⏰ Reminders before review

• Contributor guidelines followed
• All formatters and local linters executed and passed
• Written new unit and / or integration tests where applicable
• Protected functional changes with optionality (feature flags)
• Used internationalization (i18n) for all UI strings
• CI builds passed
• Communicated to DevOps any deployment requirements
• Updated any necessary documentation (Confluence, contributing docs) or informed the documentation team

🦮 Reviewer guidelines

• 👍 (:+1:) or similar for great changes
• 📝 (:memo:) or ℹ️ (:information_source:) for notes or general info
• ❓ (:question:) for questions
• 🤔 (:thinking:) or 💭 (:thought_balloon:) for more open inquiry that's not quite a confirmed issue and could potentially benefit from discussion
• 🎨 (:art:) for suggestions / improvements
• ❌ (:x:) or ⚠️ (:warning:) for more significant problems or concerns needing attention
• 🌱 (:seedling:) or ♻️ (:recycle:) for future improvements or indications of technical debt
• ⛏ (:pick:) for minor or nitpick changes

[codecov]

Codecov Report

Attention: Patch coverage is 2.04082% with 48 lines in your changes missing coverage. Please review.

Project coverage is 41.64%. Comparing base (d4c486e) to head (58cf8b1).
Report is 189 commits behind head on main.

Files with missing lines	Patch %	Lines
src/Api/Billing/Controllers/StripeController.cs	0.00%	38 Missing ⚠️
...ling/Models/Responses/CalculateTaxResponseModel.cs	0.00%	4 Missing ⚠️
...illing/Models/Requests/CalculateTaxRequestModel.cs	0.00%	3 Missing ⚠️
src/Core/Services/Implementations/StripeAdapter.cs	25.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4874      +/-   ##
==========================================
- Coverage   41.66%   41.64%   -0.02%     
==========================================
  Files        1360     1363       +3     
  Lines       63888    63950      +62     
  Branches     5862     5863       +1     
==========================================
+ Hits        26620    26634      +14     
- Misses      36061    36109      +48     
  Partials     1207     1207              

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[github-actions]

Checkmarx One – Scan Summary & Details – 6b11b94c-851c-4341-b8dd-376629e7fca3

New Issues

Severity	Issue	Source File / Package	Checkmarx Insight
	Unpinned Actions Full Length Commit SHA	/build.yml: 598	Pinning an action to a full length commit SHA is currently the only way to use an action as an immutable release. Pinning to a particular SHA helps...

Fixed Issues

Severity	Issue	Source File / Package
	Unpinned Actions Full Length Commit SHA	/build.yml: 582
	Unpinned Actions Full Length Commit SHA	/build.yml: 631

[cyprain-okeke]

Looks good, Please attach the recording

[jonashendrickx]

Looks good, Please attach the recording

@cyprain-okeke This is just the backend part though.

Request

{
    "amount": 100,
    "billingAddressCountry": "ES",
    "billingAddressPostalCode": "30709"
}

Response

{
    "salesTaxAmount": 0,
    "salesTaxRate": 0.0,
    "taxableAmount": 100,
    "totalAmount": 100
}

For New York:

Response

{
    "salesTaxAmount": 8,
    "salesTaxRate": 0.08,
    "taxableAmount": 100,
    "totalAmount": 108
}

[amorask-bitwarden]

Looks good - just a few requests.

[jonashendrickx]

If it gets more complex we need to calculate this with the product identifier from Stripe if we use different tax codes per product.

[cturnbull-bitwarden]

We may need to wait on this PR until we get some clarity, but Stripe charges a fee per request when calculating tax. The fee is variable, and it might already be included in our plan, but we need to make sure we understand this first before we merge this.

https://stripe.com/tax/pricing

https://support.stripe.com/questions/understanding-stripe-tax-pricing