Day 4

Today's Objective

RFP process, contract negotiation, SLAs, avoiding vendor lock-in, due diligence

What You'll Cover Today

Day 4 of CTO Skills in 5 Days pushes into advanced territory. You have enough foundation now to tackle real-world complexity. Today's exercise is more open-ended than earlier days — that's intentional.

RFP

Understanding RFP is the core goal of Day 4. The concept is straightforward once you see it in practice — most confusion comes from skipping the mental model and jumping straight to implementation. Start with the model, then write the code.

# RFP — Working Example
# Study this pattern carefully before writing your own version

class RFPExample:
    """
    Demonstrates core RFP concepts.
    Replace placeholder values with your real implementation.
    """
    
    def __init__(self, config: dict):
        self.config = config
        self._validate()
    
    def _validate(self):
        required = ['name', 'type']
        for field in required:
            if field not in self.config:
                raise ValueError(f"Missing required field: {field}")
    
    def process(self) -> dict:
        # Core logic goes here
        result = {
            'status': 'success',
            'topic': 'RFP',
            'data': self.config
        }
        return result

# Usage
example = RFPExample({
    'name': 'my-implementation',
    'type': 'rfp'
})
output = example.process()
print(output)

SLAs

SLAs is the practical application of RFP in real projects. Once you understand the underlying model, SLAs becomes the natural next step.

lock-in

lock-in rounds out today's lesson. It connects RFP and SLAs into a complete picture. You'll use all three concepts together in the exercise below.

Common Mistakes on Day 4

• Skipping the fundamentals — RFP requires understanding the underlying model before you can apply it correctly. Read the section twice if needed.
• Ignoring error messages — error messages for SLAs are usually precise. Read them carefully before searching online.
• Hard-coding values — anything that might change between environments belongs in configuration, not in your source code.
• Not testing edge cases — the happy path is not enough. What happens with empty input? With unexpected types? With network failures?

1. Set up your environment for today's topic: install required tools and verify the basics work before writing any logic.
2. Implement a minimal working version of RFP using the code example in this lesson as your starting point.
3. Extend your implementation to incorporate SLAs — this is where the two concepts connect.
4. Test your implementation with both valid and invalid inputs. What happens at the boundaries?
5. Review your code: is there anything you'd name differently? Any function doing more than one thing? Refactor one thing.

Extend today's exercise by adding one feature that wasn't in the instructions. Document what you built in a comment at the top of the file. This habit of going one step further is what separates engineers who grow fast from those who stay stuck.