It usually starts with a simple Slack message from a Project Manager: “Hey, we need to move our helpdesk data from System A to System B. Can we just get the engineering team to whip up a script for that?”
Your Lead Engineer looks at the API documentation and shrugs: “Sure. It’s just a few GET requests and some POST requests. I can knock it out this weekend.”
Stop.
As a technical leader, you are about to walk into the classic “Build vs. Buy” Trap. What looks like a “weekend project” is often a 2-month quagmire of API rate limits, data validation errors, and maintenance headaches.
The question isn’t “Can my team build this?” Of course they can; they are smart engineers. The question is “Should my team build this?”
In this guide, we’ll analyze why “rolling your own” migration scripts is almost always a bad financial decision compared to outsourcing or buying specialized solutions.
The “Happy Path” Fallacy
Engineers are optimists. When they estimate time for a migration script, they plan for the Happy Path:
- Read Data from System A.
- Write Data to System B.
- Done.
The Reality Path usually looks like this:
- Read Data from System A.
- Error 429: Too Many Requests. (Dev stops to write backoff/retry logic).
- Error 500: Server Error. (Dev stops to write error logging).
- Data Error: “User ID 404 not found.” (Dev stops to write dependency mapping logic).
- Encoding Error: “Invalid character \xE2.” (Dev stops to write text sanitization).
Suddenly, a 100-line script balloons into a 2,000-line ETL (Extract, Transform, Load) application that needs its own QA cycle.
The Hidden Complexity of Migrations
If you choose to build in-house, you aren’t just moving data; you are building a temporary software product. You need to handle:
1. API Rate Limits & Throttling
Most SaaS vendors limit you to ~700 requests per minute. If you have 500,000 records, a linear script will take 12+ hours to run.
- The Risk: If the script crashes at hour 11, does it have “Checkpoint/Resume” logic? Or do you have to delete everything and start over?
2. Dependency Mapping
You can’t migrate a Ticket until you have migrated the User. You can’t migrate the User until you have migrated their Company. Your internal script needs a sophisticated “Order of Operations” engine to prevent foreign key violations.
3. Attachments & Inline Images
Downloading and re-uploading terabytes of attachments requires managing streams, memory buffers, and MIME types. It is rarely as simple as a text transfer.
The Financials: The Opportunity Cost
The biggest cost of an in-house migration isn’t the engineer’s salary. It’s Opportunity Cost.
Every hour your Senior Engineer spends parsing a CSV file is an hour they aren’t building features for your actual customers.
Let’s do the math:
- Internal Build:
- Engineer Cost: $150/hour (fully loaded).
- Time: 40 Hours (Coding) + 20 Hours (Testing/Fixing).
- Hard Cost: $9,000.
- Opportunity Cost: Delaying your core product roadmap by 1.5 weeks.
The Outsourced/Buy Option:
- Specialized Solution/Tool: Often a flat fee (e.g., $2k – $5k).
- Engineer Time: 5 Hours (Configuration & Oversight).
- Hard Cost: ~$3,000 – $6,000.
- Opportunity Cost: Near Zero. Your team stays focused on shipping value.
The Result: Buying or outsourcing is often 30-50% cheaper purely on hard costs, and infinitely cheaper when you factor in roadmap momentum.
When Should You Build In-House?
Despite the costs, there is one scenario where building makes sense: Security & Compliance.
If you are a Defense Contractor, a Bank, or a Healthcare provider, and your data absolutely cannot leave your Virtual Private Cloud (VPC), you may be forced to build internal tools. In this case, the cost is justified by the compliance requirement.
The Verdict
Migrations are “Undifferentiated Heavy Lifting.” Building a great migration script doesn’t make your product better, it doesn’t impress your customers, and it doesn’t generate revenue.
Your engineers should be building the future of your company, not the plumbing for your database. Unless you have a strict compliance reason to do otherwise, the smart move is almost always to outsource the problem to specialized tools or experts who solve this problem every day.