How to Migrate From a Custom Wholesale Portal to an App-Based Solution

Quick Answer

Migrating from a custom-built portal typically means first documenting the existing pricing logic, since custom code is often undocumented and understood by only one or two people, then recreating that logic as Wholesale Pricing Discount B2B's tag-based rules, which come with ongoing support and updates a custom system does not.

Migrating From a Wholesale Portal to an App-Based Solution

A custom-built wholesale portal, coded specifically for one business rather than a supported third-party platform, tends to accumulate technical debt over time, undocumented logic, a single developer who understands the system, and a growing cost to maintain or extend it.

This guide focuses specifically on the situation where a business built its own bespoke wholesale system and is now considering the move to a supported app, distinct from migrating between two established platforms.

This guide covers migrating from a custom-built wholesale portal to an app-based solution, addressing the specific technical debt that usually drives this decision.

What Technical Debt Typically Drives This Migration?

Custom-built systems typically accumulate technical debt through undocumented pricing logic embedded directly in code, dependency on one or two people who understand how the system actually works, and a growing cost or risk every time the business needs to extend or fix something, since there is no vendor support to rely on.

Who Needs to Migrate From a Custom Wholesale Portal?

• Businesses running a custom-built wholesale system with undocumented pricing logic
• Companies dependent on one specific person who understands the existing system
• Sellers facing rising maintenance costs or risk with their custom portal
• Teams wanting ongoing vendor support rather than in-house custom development
• Distributors wanting a more maintainable, documented pricing structure going forward
• Anyone whose custom system was built for a business that has since outgrown its original design

Why This Migration Matters for Your Business

• Undocumented custom logic creates real business risk if the one person who understands it leaves
• A supported app receives ongoing updates and support a custom system does not
• Migrating forces documentation of pricing logic that may have never existed clearly before
• This reduces the growing cost and risk of maintaining custom code indefinitely
• Getting this right protects business continuity beyond dependency on specific individuals
• This is often overdue by the time a business actually starts the migration

For a full breakdown of what Shopify includes natively and where it stops, see our comparison of native B2B versus third-party apps.

How to Migrate From a Custom Portal to an App-Based Solution

Step 1: Prepare Your Store and Customer Tags

Document the existing custom pricing logic thoroughly before building anything new, since this documentation step is often the most valuable and most overdue part of the process.

• Work with whoever understands the custom system to document its pricing logic completely
• Identify every customer tier, rule, and exception currently embedded in the custom code
• Create matching customer tags in Shopify admin for each documented tier

Step 2: Install and Configure Wholesale Pricing Discount B2B

Install Wholesale Pricing Discount B2B and recreate the documented pricing logic as tag-based rules, verifying each one against the original custom system's behavior.

• Connect the app and set up percentage discounts matching the documented custom logic
• Recreate any custom exceptions as per-customer overrides
• Confirm bulk CSV import can speed up recreating pricing at scale if applicable

Step 3: Create the Pricing or Discount Rules

Build out every rule and exception from your documentation, checking each one against the original custom system's actual behavior for real accounts.

• Set percentage discounts and volume pricing matching the documented custom logic
• Recreate order minimums and any other rules the custom system enforced
• Confirm net terms and shipping rules match what the custom system provided

Step 4: Test With a Tagged Test Customer

Test the recreated pricing against the original custom system directly, comparing real account pricing side by side before considering the migration complete.

• Compare pricing for several real accounts between the custom system and the new app-based setup
• Confirm every documented exception transferred correctly
• Ask Sidekick which customers are in a specific tier group to confirm tagging matches your documented original structure

Step 5: Go Live

Once pricing matches exactly, migrate accounts fully and retire the custom system, keeping its final state documented for reference.

• Publish the new app-based pricing structure to your live store
• Communicate the transition clearly to affected wholesale accounts
• Retire the custom system only after a full verification period on the new setup

Custom Portal Migration Examples

Specialty Food Distributor (Food and beverage)
Problem: Ran a custom-built wholesale portal that only one former developer fully understood, creating significant business risk since that person had since left.
Setup: Worked to document the existing pricing logic as thoroughly as possible, then recreated it as tag-based rules through Wholesale Pricing Discount B2B, verified against real account data.
Result: The business gained a documented, supported pricing system no longer dependent on one specific person's knowledge.

Industrial Parts Supplier (Industrial goods)
Problem: Faced rising costs every time a small change was needed to their custom wholesale system, since each change required hiring a developer familiar with the specific codebase.
Setup: Migrated to an app-based solution with ongoing vendor support, eliminating the need for custom development on routine pricing changes.
Result: Routine pricing adjustments became something staff could handle directly, without needing to hire a developer for each change.

Read more case studies for our apps.

Best Practices

• Document existing custom pricing logic thoroughly before building anything new
• Work with whoever understands the custom system while that knowledge is still available
• Test recreated pricing against the original system for real accounts, not just hypothetical ones
• Use bulk CSV import to speed up recreating pricing at scale where applicable
• Retire the custom system only after a full verification period on the new setup
• Keep the custom system's final documented state on file for reference

Summary

Migrating from a custom-built wholesale portal to an app-based solution typically starts with documenting pricing logic that may have never been clearly written down before, since custom systems tend to accumulate exactly this kind of undocumented risk over time. Recreating that logic as supported, documented tag-based rules protects business continuity beyond dependency on any one person's knowledge of the original code. For more on the pricing tools this migration moves toward, see our comparison of native B2B versus third-party apps.

To migrate documented pricing logic from a custom system, try Wholesale Pricing Discount B2B.