As mobile engineers, we are often under a pressure for delivering new features, or iterating rapidly. But, without a solid technical specification, even the best intentioned projects can go awry, miss edge cases or cause regressions.
A well crafted tech spec document can act as a blueprint; also it helps align engineers, product managers, design team, QA as well as data team. It helps anticipate risks in advance and when done right it becomes a reference document for years.
In this guide, I will share a real structure that I have used for building iOS features over the years (will also share an example for reference).
So, let’s start:
📁 Tech Spec Structure
🏗️ Project Details:
1. Context
In this section, summarize the trigger for the work; it could be about adding new feature to an existing app, critical bug fix, data trends or can cover competitive gaps.
Example:
Less than 9% of users grant push notification permissions during the first session. The system prompt appears too early in the flow after account creation and feels abrupt to users.
2. Problem
In this section, describe the core problem include technical or UX issues and their impact on business or product goals.
Example:
The native iOS push permission prompt is shown before users can understand why its needed. Once dismissed by the user, we cannot prompt the user again and hence app’s reengagement opportunity is lost.
3. Hypothesis
In this section, state your working theory and the expected outcome if this feature works as intended. Try to connect it to the product goals.
Example:
If we show a user educational screen before showing the native prompt, users will be more likely to opt-in. We expect at least a 15% increase in push opt-in rates and improved user trust.
4. Test plan
In this section, list success criteria and the metrics that will be tracked. Include, the exact metrics names, tools used to track it and important segmentation (for eg: user geo, device, app version, etc)
Example:
We will track:
- push notif granted: User granted the permission
- user onboarding flow completed: This will help understand any friction or drop in the flow.
5. Impact/Opportunity
In this section, quantify the potential upside; this will help the stakeholders understand the cost benefit and prioritize correctly.
Example:
Improving opt-in from 8% to 23% could help increase the push notification reach by 3x; which is historically directly correlated with ~2% increase in 7-day app retention.
6. Scope
In this section, define the boundaries for the project; this will help avoid any misunderstanding or unintentional scope creep later.
Example:
In scope –
- New education screen
- Native prompt integration
- iPhone devices only
Out of scope –
- Android changes
7. Design/Content spec
In this section, include the wire frames (figma links if any or whatever tools used by the design team); resource locations for assets, animations, etc.
📋 Non-Tech Details:
1. Cross-Functional Inputs
In this section, list all the non code dependencies that can impact this project
Example:
- Legal team review – If this feature can cause any privacy issues for the users.
⚙️ Tech Details:
1. Eng Explorations
In this section, outline the engineering decision around how to implement this feature including reuse of existing components, selection of UI frameworks, any architectural inputs, etc.
Example:
Option A – Reuse existing onboarding screen
- Pros: Integrated; analytics already present
- Cons: Flow is coupled to logic and auth screens (so hard to isolate, and might require big refactor)
Option B (Chosen) – Standalone UIKit ViewController
- Pros: Modular, testable
- Cons: Slight duplication of layout logic
2. Risks
In this section, list potential risk for the project; it could be performance concerns, more server capacity needs, etc
Example:
If user does not complete the education flow, they might not see the native prompt.
3. A/B Test Setup
In this section, just quickly highlight the test setup. Share any code pointers if needed.
Example:
- Control: No change (old flow with prompt after sign up)
- Test: Show education screen
4. Code pointers
In this section, share the code pointers where the implementation will take place, which module to use, etc (You can also come back and fill this section after the implementation is done)
🛠 Execution:
1. Timeline
In this section, share the exact timeline for the execution for the project. Be precise and add some buffer for unforeseen issues.
Example:
|
Item |
Milestone |
Status |
ETA |
Estimate |
|---|---|---|---|---|
|
1. |
Project Planning |
In Progress |
20 March |
1.5 weeks |
|
2. |
Design Approval |
In Progress |
24 March |
2 weeks |
|
3. |
Code changes |
Not Started |
8 April |
2 weeks |
|
4. |
QA Testing |
Not Started |
21 April |
0.5 week |
|
5. |
Public A/B Test |
Not Started |
25 April |
2 weeks |
2. Weekly meetings:
In this section, summarize the weekly standup meetings; keep track of the progress, discuss any blockers, etc.
Example:
15 March:
- Project planning progress
- Get updates from Design team
21 March:
- Design update
- Eng execution timeline discuss
Final Thoughts:
Tech specs isn’t some internal document; they are a form of technical leadership. Writing a strong tech spec shows you are thinking beyond just code; you are aligning people, goals and the system.
Next time, you are asked to build a new app or extend new feature for your app, take time to spec it first. It’s will be worth it 😀
