The Less Obvious Trade-Offs of Building With a Development Agency
Coding agencies are often the rational decision when building an early product. Particularly for non-technical founders, agencies provide the velocity and assurance that appeal to the unique urgency of getting a tangible solution live for market validation.
The issue isn’t that this approach is wrong - rather that the risk profile is rarely understood or made explicit. While this due diligence is not the responsibility of agencies themselves to disclose, the potential downsides are typically non-obvious and require a level of technical prudence that may be overlooked by the target audience. These issues are unfortunately latent and surface inconveniently when scaling or pivoting.
Functionality and the Cost of Change
One of the most commonly overlooked aspects of early software projects involves conflating current functionality with overall health. Initial systems seem sufficient out of the box due to their minimal usage, narrow requirements and unchallenged assumptions. This provides little insight into how the system will behave once stakes increase.
The most significant long-term risk in these situations is rarely correctness in the present - it is the cost of change in the future. I emphasise this distinction, as many delivery-optimised systems are rarely meaningfully evaluated by that metric. The reason is simple: incentive mismatch.
Development agencies optimise to deliver defined scope within a finite timeline. By contrast, founders optimise to preserve optionality - that is, the agility to adapt while understanding more about users, markets and evolving constraints. Neither incentive is unreasonable, but they are not the same.
This gap often manifests in the accumulation of small concessions that never get revisited. Deferred trade-offs and temporary solutions become the status quo, gradually eroding a system’s elasticity over time. Modest changes turn into a cat-and-mouse chase across the codebase - increasing effort and risk while making clashes amongst developers more frequent. Inherited codebases often resemble a post-mortem of these unresolved markers - decisions once acknowledged but postponed for an undefined future owner.
These patterns are rarely signs of negligence - they are unfortunate evidence of work completed under delivery pressure where the cost of future flexibility is difficult to rationalise in the moment.
Early Trade-Offs That Become Long-Term Constraints
Many agencies augment their efficiency by implementing economies of scale through standardisation to sustain operation. This results in a common reliance on internal templates and shared scaffolding to guide their architectural decisions across projects.
While functionally sound, these reusable components can lead to systems that are resistant to change. Dependencies age quietly, and structural choices that were once contemporary now become friction points as your team expands or pivots. What was once decided as the best blanket foundation for many solutions can accumulate into an expensive obstacle to later adapt and hinder collaborative development.
Inheriting the tech stack at Rease, for example, revealed structural decisions that were reasonable at the time but introduced real friction as the product evolved. The application worked as intended, but required an asymmetric amount of effort to extend it safely. The cost wasn’t visible at launch, but rather emerged with growth. Addressing this required significant investigation and engineering effort to determine whether the existing implementation could be safely extended, or whether it needed to be reworked to meet more modern requirements.
Knowledge Dependency and Decision Latency
Another dormant risk lies in where system knowledge resides. Many agency engagements separate critical context from the company - with resultant artefacts depicting what exists, but rarely why certain decisions were made.
This develops a habit of implicit dependency: the assumption that expertise can always be accessed if needed. This is brittle in the face of outages, product pivots, or when onboarding in-house engineers. Ownership entails more than retaining the source code - it requires contextual familiarity with the trade-offs that shaped the system and what that could mean for the future.
The inherent distance of external agencies and prevalence of those located offshore only amplify this divide through geographic and time-zone barriers. Important decisions must travel through several layers before implementation, and the feedback loop slows down. This matters most in fields where trust, timing and money are critical.
In earlier transaction-heavy iterations of Rease, small delays in diagnosis and response had a disproportionate impact on user confidence. The problem wasn’t necessarily technical performance - it was the bottleneck between recognition and action. In high-importance systems, that delay compounds risk quickly.
Security Risk Under Delivery Pressure
Security-related decisions are often implicitly placed in the trust of the agency when building systems. There are undoubtedly other factors at play, but these are the patterns that have most reliably surfaced through my own experience. Credential handling, secret management, environment separation, and access control tend to hide in the shadow of more visible progress indicators. Unlike product features which create immediate user-facing value and attractive demonstrations, these areas of security frequently receive less attention.
This is almost certainly due to prioritisation rather than negligence. Under delivery pressure, work that slows visible progress is difficult to justify - particularly when systems are not under sustained scrutiny or operating at scale. After handover, exposure and risk become more difficult to assess or audit, with internal engineers inheriting not just the code, but the responsibility for its vulnerabilities. Uncertainty now becomes a liability: what was presumed safe must now be proven to be so.
Rease’s post-handover reviews surfaced concerns around historical credential handling that required full rotation and regression testing in an effort to restore confidence. The underlying risk was only realised once the system became more directly vested with the company’s internal engineers, and the absence of clarity introduced enough uncertainty to warrant corrective action.
Security issues rarely announce themselves at launch - they tend to surface later. Security risk is not postponed because it is ignored, but because the consequences are asymmetric: invisible early, expensive later.
A Final Perspective
Typically, none of these issues appear during MVP validation. The risks emerge later, when the product begins to matter more rather than less. By this point, the cost of change has increased, the context behind key decisions has dissolved, and the key differentiator of any startup amongst its incumbents - its agility - is impacted.
This does not make agency-built systems inherently flawed. Agencies may be the correct decision in many circumstances, particularly when project scope is discrete, expectations around post-delivery ownership are clear, and there exists some internal technical oversight during engagement.
In practice, agency collaboration works best when paired with a clear understanding of the signals indicating long-term risk. That includes where foundational system knowledge is held and reliably documented, frequently assess how easily a hypothetical new engineer can make a meaningful change, whether security practices are made transparent and reviewable, which decisions were deferred and who owns revisiting them, and how much of the system’s safety depends on people no longer involved once delivery concludes.
Most founders choose agencies with proper intentions. Speed matters, and hindsight is always clearer than reality in the moment. The goal is not to avoid agency work altogether, but to engage with a clearer understanding of the implications associated. I’ve witnessed many expensive problems that rarely broke early, but rather quietly hindered change later.