July 22, 2024
Linking Modular Structure to Growth Groups

This text will show the direct hyperlinks between totally different cell scaling points,
technical structure and groups. At Thoughtworks we work with many giant enterprises
every presenting totally different issues and necessities when scaling their cell presence.
We determine two frequent issues seen in giant enterprise cell app growth:

  1. A gradual lengthening of the time it takes to introduce new options to a
    market app
  2. Inner function disparity arising from an absence of compatibility/reusability
    between in-house
    market apps

This text charts the journey one in every of our purchasers took when attempting to deal with these
points. We inform the story of how their organisation had previously, gravitated in the direction of
appropriate options, however was not capable of see the anticipated advantages because of a
misunderstanding of how these options had been intrinsically

We develop this statement by recounting how the identical organisation was capable of obtain a
60% discount in common cycle time, an 18 fold enchancment in growth prices and an
80% discount in crew startup prices by shifting their team topologies to match a
modular structure whereas on the similar time, investing within the developer

Recognising the Indicators

Regardless of one of the best of intentions, software program usually deteriorates over time, each in
high quality and efficiency. Options take longer to get to market, service outages
develop into extra extreme and take longer to resolve, with the frequent consequence that these
engaged on the product develop into pissed off and disenfranchised. A few of this may be
attributed to code and its upkeep. Nevertheless, inserting the blame solely on code
high quality feels naive for what’s a multifaceted problem. Deterioration tends to develop
over time by means of a posh interaction of product choices, Conway’s legislation, technical
debt and stationary structure.

At this level, it appears logical to introduce the organisation this text relies
round. Very a lot a big enterprise, this enterprise had been experiencing a gradual
lengthening of the time it took to introduce new options
into their retail
cell utility.

As a starter, the organisation had appropriately attributed the friction they had been
experiencing to elevated complexity as their app grew- their current growth
crew struggled so as to add options that remained coherent and in step with the
current performance. Their preliminary response to this had been to ‘simply add extra
builders’; and this did work to some extent for them. Nevertheless, ultimately it grew to become
obvious that including extra folks comes on the expense of extra strained communication
as their technical leaders began to really feel the elevated coordination overhead.
Therefore the ‘two
rule promoted at Amazon: any crew ought to be sufficiently small to be fed by two
pizzas. The speculation goes that by limiting how massive a crew can develop into, you keep away from the
state of affairs the place communication administration takes extra time than precise worth creation.
That is sound idea and has served Amazon nicely. Nevertheless, when contemplating an
current crew that has merely grown too massive, there’s a tendency in the direction of ‘cargo
culting’ Amazon’s instance to try to ease that burden…

Limiting Cognitive Load

Certainly, the organisation was no exception to this rule: Their as soon as small monolith had
develop into more and more profitable however was additionally unable to copy the required charge of
success because it grew in options, obligations and crew members. With looming
function supply deadlines and the prospect of a number of model markets on the
horizon, they responded by splitting their current groups into a number of smaller,
related sub-squads – every crew remoted, managing a person market (regardless of
related buyer journeys).

This actually, made issues worse for them, because it shifted the communication tax from
their tech management to the precise crew itself, whereas easing none of their
increasing contextual load. Realizing that communication and coordination was sapping
an growing period of time from these tasked with precise worth creation, our
preliminary suggestion concerned the thought of ‘cognitive
outlined by Skelton & Pais (2019). This entails the
separation of groups throughout singular advanced or sophisticated domains. These seams
inside software program can be utilized to formulate the aforementioned ‘two pizza sized groups’
round. The result’s a lot much less overhead for every crew: Motivation rises, the
mission assertion is clearer, whereas communication and context switching are shrunk
right down to a single shared focus. This was in idea an amazing answer to our consumer’s
drawback, however can really be deceptive when thought-about in isolation. The advantages
from cognitive load limitation can solely actually be realised if an utility’s area
boundaries are actually nicely outlined and constantly revered contained in the code.

Area Pushed Self-discipline

Design (DDD) is helpful for organising advanced logic into manageable teams
and defining a typical language or mannequin for every. Nevertheless, breaking up an
utility into domains is just a part of an ongoing course of. Conserving tight management
of the
bounded context is as vital as defining the domains themselves.
Analyzing our consumer’s utility’s code we encountered the frequent lure of a transparent
preliminary funding defining and organising area obligations appropriately, solely
to have began to erode that self-discipline because the app grew. Anecdotal proof from
stakeholders advised that perpetually busy groups taking shortcuts pushed by
pressing product
necessities had develop into the norm
for the crew. This in flip had contributed
to a progressive slowing of worth supply because of the accumulation of technical
debt. This was highlighted additional nonetheless by a measurable downtrend within the
utility’s Four
Key Metrics
because it grew to become tougher to launch code and more durable to debug

Additional warning indicators of a poorly managed bounded context had been found by means of
frequent code evaluation instruments. We discovered a codebase that had grown to develop into tightly
coupled and missing in cohesion. Extremely
code is troublesome to vary with out affecting different elements of your system.
Code with low cohesion has many obligations and issues that don’t match inside
its remit, making it obscure its function. Each these points had been
exacerbated over time because the complexity of every area inside our consumer’s app had
grown. Different indications got here with reference once more to cognitive load. Unclear
boundaries or dependencies between domains within the utility meant that when a
change was made to at least one, it might possible involuntarily have an effect on others. We observed that
due to this, growth groups wanted data of a number of domains to resolve
something which may break, growing cognitive load. For the organisation,
implementing rigorous management of every domain-bounded context was a progressive step
ahead in making certain data and accountability lay in the identical place. This
resulted in a limitation of the ‘blast radius’ of any modifications, each within the quantity of
work and data required. As well as, bringing in tighter controls within the
accruing and addressing of technical debt ensured that any brief time period
‘domain-bleeds’ might be rejected or rectified earlier than they may develop

One other metric that was lacking from the organisation’s cell purposes was optionality
of reuse
. As talked about earlier, there have been a number of current, mature model
market purposes. Function parity throughout these purposes was low and a
willingness to unify right into a single cell app was troublesome because of a want for
particular person market autonomy. Tight coupling throughout the system had diminished the flexibility
to reuse domains elsewhere: Having to transplant most of an current cell app simply
to reuse one area in one other market introduced with it excessive integration and ongoing
administration prices. Our utilisation of correct domain-bounded context management was a
good first step to modularity by discouraging direct dependencies on different domains.
However as we discovered was not the one motion we wanted to take.

Domains that Transcend Apps

Situation 1 – ‘The Tidy Monolith’

When considered as a single utility in
isolation, merely splitting the app into
domains, assigning a crew, and managing their coupling (in order to not breach
their bounded contexts) works very nicely. Take the instance of a function request
to a person utility:

function request is handed to the app squads that personal the related area. Our
bounded context implies that the blast radius of our change is contained inside
itself, that means our function might be constructed, examined and even deployed with out
having to
change one other a part of our utility. We velocity up our time to market and permit
a number of options to be developed concurrently in isolation. Nice!

Certainly, this labored nicely in a singular market context. Nevertheless as quickly as we
tried to deal with our second scaling problem- market function disparity arising
from an absence of reusability
– we began to run into issues.

Situation 2 – ‘The Subsequent Market Alternative’

The subsequent step for the group on its quest for modularity of domains was to
obtain speedy growth financial savings by transplanting elements of the ‘tidy monolith’
into an current market utility. This concerned the creation of a typical
framework (facets of which we contact on later) that allowed
functionalities/domains to be reused in a cell utility outdoors its origin.
To raised illustrate our methodology, the instance under reveals two market
purposes, one within the UK, the opposite, a brand new app based mostly out of the US. Our US
based mostly utility crew has determined that along with their US particular domains
they want to make use of each the Loyalty Factors and Checkout domains as
a part of their utility and have imported them.

For the organisation, this appeared to imply an order of magnitude growth
saving for his or her market groups vs their conventional behaviour of rewriting area
performance. Nevertheless, this was not the tip of the story- In our haste to maneuver
in the direction of modularity, we had didn’t consider the prevailing
communication buildings of the organisation that finally dictated the
precedence of labor. Creating our earlier instance as a way to clarify: After
utilizing the domains in their very own market the US crew had an concept for a brand new function
in one in every of their imported domains. They don’t personal or have the context of that
area so that they contact the UK utility crew and submit a function request. The
UK crew accepts the request and maintains that it appears like “an amazing concept”,
solely they’re at the moment “coping with requests from UK based mostly stakeholders”
so it is unclear when they may be capable to get to the work…

We discovered that this battle of curiosity in prioritising area performance
limits the quantity of reuse a shopper of shared performance may count on –
this was evident with market groups changing into pissed off on the lack of progress
from imported domains. We theorized quite a lot of options to the issue: The
consuming crew may maybe fork their very own model of the area and
orchestrate a crew round it. Nevertheless, as we knew already, studying/proudly owning an
whole area so as to add a small quantity of performance is inefficient, and
diverging additionally creates issues for any future sharing of upgrades or function
parity between markets. Another choice we seemed into was contributions through pull
request. Nevertheless this imposed its personal cognitive load on the contributing crew –
forcing them to work in a second codebase, whereas nonetheless relying on help on
cross crew contributions from the first area crew. For instance, it was
unclear whether or not the area crew would have sufficient time between their very own
market’s function growth to supply architectural steering or PR evaluations.

Situation 3 – ‘Market Agnostic Domains’

Clearly the issue lay with how our groups had been organised. Conway’s
legislation is the statement that an organisation will design its enterprise
methods to reflect its personal communication construction. Our earlier examples
describe a situation whereby performance is, from a technical standpoint
from an
possession standpoint continues to be monolithic:
“Loyalty Factors was created
for the UK utility so it belongs to that crew”
. One potential
response to that is described within the Inverse
Conway Maneuver
. This entails altering the construction of growth groups
in order that they allow the chosen technical structure to emerge.

Within the under instance we advance from our earlier situation and make the
structural modifications to our groups to reflect the modular structure we had
beforehand. Domains are abstracted from a selected cell app and as a substitute are
autonomous growth groups themselves. After we did this, we observed
relationships modified between the app groups as they not had a dependency
on performance between markets. Of their place we discovered new relationships
forming that had been higher described when it comes to shopper and supplier. Our area
groups supplied the performance to their market prospects who in flip consumed
them and fed again new function requests to higher develop the area product.

The principle benefit this restructuring has over our earlier iteration is the
clarification of focus. Earlier we described a battle of curiosity that
occurred when a market made a request to vary a site originating from inside
one other market. Abstracting a site from its market modified the main focus from
constructing any performance solely for the advantage of the market, to a extra
holistic mission of constructing performance that meets the wants of its
customers. Success grew to become measured each in shopper uptake and the way it was
obtained by the tip person. Any new performance was reviewed solely on the
quantity of worth it delivered to the area and its customers total.

Give attention to Developer Expertise to Assist Modularity

Recapping, the organisation now had a topological construction that supported modularity
of parts throughout markets. Autonomous groups had been assigned domains to personal and
develop. Market apps had been simplified to configuration containers. In idea, this
all is smart – we will plot how suggestions flows from shopper to supplier fairly
simply. We are able to additionally make excessive stage utopian assumptions like: “All domains are
independently developed/deployed”
or “Shoppers
‘simply’ pull in no matter reusable domains they want to type an utility”

In apply,
nevertheless, we discovered that these are troublesome technical issues to resolve. For instance,
do you preserve a stage of UX/model consistency throughout autonomous area groups? How
you allow cell app growth if you find yourself solely accountable for a part of an
utility? How do you enable discoverability of domains? Testability? Compatibility
throughout markets? Fixing these issues is completely doable, however imposes its personal
cognitive load, a accountability that in our present construction didn’t have any
proprietor. So we made one!

A Area to Remedy Central Issues

Our new area was categorised as ‘the platform’. The platform was
primarily an all encompassing time period we used to explain tooling and steering
that enabled our groups to ship independently inside the chosen structure.
Our new area crew maintains the supplier/shopper relationship we’ve seen
already, and is accountable for enhancing the developer expertise for groups
that construct their apps and domains inside the platform. We hypothesised {that a}
stronger developer expertise will assist drive adoption of our new structure.

However ‘Developer Expertise’ (DX) is sort of a non-specific time period so we thought it
vital to outline what was required for our new crew to ship a superb one. We
granularised the DX area right down to a set of needed capabilities – the primary
being, Environment friendly Bootstrapping.

With any frequent framework there’s an inevitable studying curve. developer
expertise goals to scale back the severity of that curve the place doable. Smart
defaults and starter kits are a non-autocratic method of decreasing the friction felt
when onboarding. Some examples we outlined for our platform area:

We Promise that:

  • It is possible for you to to rapidly generate a brand new area
    with all related cell
    dependencies, frequent UI/UX, Telemetry and CI/CD infrastructure in a single
  • It is possible for you to to construct, check and run your area
    Your area will run the identical method when bundled into an app because it does

Be aware that these guarantees describe components of a self-service expertise inside a
developer productiveness platform. We subsequently noticed an efficient
platform as one which allowed groups that had been targeted round end-user
performance to focus on their mission moderately than preventing their method
by means of a seemingly infinite checklist of unproductive

The second needed functionality we recognized for the platform area was Technical
Structure as a Service
. Within the organisation, architectural capabilities additionally
adopted Conway’s legislation and consequently the accountability for structure
choices was concentrated in a separate silo, disconnected from the groups
needing the steering. Our autonomous groups, whereas capable of make their very own
choices, tended to wish some side of ‘technical shepherding’ to align on
ideas, patterns and organisational governance. After we extrapolated these
necessities into an on demand service we created one thing that appears like:

We Promise that:

  • The perfect apply we offer shall be accompanied
    with examples that you may
    use or precise steps you’ll be able to take
  • we’ll preserve an total
    image of area utilization per app and when wanted,
    orchestrate collaboration throughout verticals
  • The trail to
    manufacturing shall be seen and proper
  • We’ll work with you”

Be aware that these guarantees describe a servant
management relationship to the groups, recognizing that everybody is
accountable for the structure. That is in distinction to what some would possibly
describe as command and management architectural governance insurance policies.

One final level on the Platform Area, and one price revisiting from the
earlier instance. In our expertise, a profitable platform crew is one that’s
deeply ingrained with their buyer’s wants. In Toyota lean manufacturing, “Genchi Genbutsu” roughly interprets to “Go
and see for your self”
. The concept being that by visiting the supply of the
drawback and seeing it for your self, solely then can you know the way to repair it. We
realized {that a} crew with the main focus of enhancing developer expertise should be
capable of empathise with builders that use their product to really perceive
their wants. After we first created the platform crew, we didn’t give this
precept the main focus it deserved, solely to see our autonomous groups discover their very own
method. This finally prompted duplication of efforts, incompatibilities and an absence
of perception within the structure that took time to rectify.

The Outcomes

We’ve informed the story about how we modularised a cell app, however how profitable was it
over time? Acquiring empirical proof might be troublesome. In our expertise, having
a legacy app and a newly architected app inside the similar organisation utilizing the identical
domains with supply metrics for each is a situation that doesn’t come round too
usually. Nevertheless fortunately for us on this occasion, the organisation was giant sufficient to
be transitioning one utility at a time. For these outcomes, we evaluate two
functionally related retail apps. One legacy with excessive coupling and low cohesion
albeit with a extremely productive and mature growth crew (“Legacy monolith”). The
different, the results of the modular refactoring train we described beforehand – a
nicely outlined and managed bounded context however with ‘newer’ particular person area groups
supporting (“Area-bounded Context App”). Cycle time is an effective measure right here
because it represents the time taken to ‘make’ a change within the code and excludes pushing
an app to the store- A variable size course of that App sort has no bearing on.

Cellular App Kind Cycle Time
Legacy Monolith 17 days
Area Bounded Context (Avg) 10.3 days

Even when cycle time was averaged throughout all area groups in our second app we noticed a
vital uplift versus the Legacy App with a much less skilled crew.

Our second comparability issues optionality of re-use, or lack thereof. On this
situation we look at the identical two cell apps within the organisation. Once more, we evaluate
one requiring current area performance (with no alternative however to put in writing it
themselves) with our modular app (capable of plug and play an current area). We
ignore the frequent steps on the trail to manufacturing since they haven’t any influence on what
we’re measuring. As an alternative, we deal with the facets inside the management of the
growth crew and measure our growth course of from pre-production ‘product
log out’ to dev-complete for a single growth pair working with a designer

Integration Kind Avg Growth Time
Non-modular 90 days
Modular 5 days

The dramatically totally different figures above present the ability of a modular structure in
a setting that has a enterprise want for it.

As an apart, it’s price mentioning that these exterior components we’ve excluded
also needs to be measured. Optimising your growth efficiency could reveal different
bottlenecks in your total course of. For instance, if it takes 6 months to create a
launch, and governance takes 1 month to approve, then governance is a relatively
small a part of the method. But when the event timeline might be improved to five
days, and it nonetheless takes 1 month to approve, then compliance
could develop into the following bottleneck to optimise.

One different benefit not represented within the outcomes above is the impact a crew
organised round a site has on integration actions. We discovered autonomous
area groups naturally seconding themselves into market utility groups in an
try to expedite the exercise. This, we consider, stems from the shift in focus of
a site squad whereby success of its area product is derived from its adoption.

We found two concentric suggestions loops which influence the speed of adoption. The
outer, a superb integration expertise from the patron of the area (i.e. the app
container). This can be a developer-centric suggestions loop, measured by how simply the
shopper may configure and implement the area as a part of their total
brand-specific product providing. The internal, a superb finish person expertise – how nicely
the general journey (together with the built-in area) is obtained by the patron’s
market buyer. A poor shopper expertise impacts adoption and finally dangers
insulating the area crew from the precise customers of the aptitude. We discovered that
area groups which collaborate intently with shopper groups, and which have direct
entry to the tip customers have the quickest suggestions loops and consequently had been the
most profitable.

The ultimate comparability price mentioning is one derived from our Platform area.
Beginning a brand new piece of area performance is a time consuming exercise and provides
to the general growth value for performance. As talked about earlier, the
platform crew goals to scale back this time by figuring out the ache factors within the course of
and optimising them – enhancing the developer expertise. After we utilized this mannequin
to area groups inside our modular structure we discovered an over 80% discount in
startup prices
per crew. A pair may obtain in a day actions that had
been estimated for the primary week of crew growth!


By now you must have fairly a rosy image of the advantages of a modular structure
on cell. However earlier than taking a sledgehammer to your ailing monolithic app, it is
price making an allowance for the restrictions of those approaches. Firstly, and certainly most
importantly, an architectural shift corresponding to this takes a number of ongoing time and
. It ought to solely be used to resolve critical current enterprise issues
round velocity to market. Secondly, giving autonomy to area groups might be each a
blessing and a curse. Our platform squad can present frequent implementations within the
type of wise defaults however finally the alternatives are with the groups themselves.
Naturally, coalescing on platform necessities corresponding to frequent UI/UX is within the
curiosity of the area squads in the event that they want to be included/accepted right into a market
app. Nevertheless, managing bloat from related inside dependencies or eclectic
is difficult. Ignoring this drawback and permitting the general app to
develop uncontrolled is a recipe for poor efficiency within the fingers of the shopper.
Once more, we discovered that funding in technical management, together with strong
guardrails and tips helps to mitigate this drawback by offering
structure/design oversight, steering and above all communication.


To recap, in the beginning of this text we recognized two vital supply
issues exhibited in an organisation with a multi app technique. A lengthening of
the time it took to introduce new options into manufacturing
and an growing
disparity between different related in home purposes
. We demonstrated that
the answer to those issues lies not in a single technique round technical
structure, crew construction or technical debt, however in a concurrently evolving
composite of all these facets. We began by demonstrating how evolving crew
buildings to help the specified modular and domain-centric structure improves
cognitive and contextual load, whereas affording groups the autonomy to develop
independently of others. We confirmed how a pure development to this was the
elevation of groups and domains to be agnostic of their originating
utility/market, and the way this mitigated the results of Conway’s legislation inherent with
an utility monolith. We noticed that this variation allowed a shopper/supplier
relationship to naturally happen. The ultimate synchronous shift we undertook was the
identification and funding within the ‘platform’ area to resolve central issues
that we noticed as a consequence of decoupling groups and domains.

Placing all these facets collectively, we had been capable of show a 60% discount in
cycle time
averaged throughout all modular domains in a market utility. We additionally
noticed an 18 fold enchancment in growth value when integrating modular
domains to a market app moderately than writing from scratch. Moreover, the deal with
engineering effectiveness allowed our modular structure to flourish because of the 80%
in startup prices
for brand spanking new domains and the continuing help the ‘platform crew’
supplied. In real-terms for our consumer, these financial savings meant having the ability to capitalise
on market alternatives that had been beforehand thought-about far too low in ROI to
justify the trouble – alternatives that for years had been the uncontested domains
of their opponents.

The important thing takeaway is {that a} modular structure intrinsically linked to groups might be
extremely useful to an organisation below the best circumstances. Whereas the
outcomes from our time with the highlighted organisation had been wonderful, they had been
particular to this particular person case. Take time to grasp your individual panorama, look
for the indicators and antipatterns earlier than taking motion. As well as, don’t
underestimate the upfront and ongoing effort it takes to carry an ecosystem like
that which we’ve described collectively. An in poor health thought-about effort will greater than
possible trigger extra issues than it solves. However, by accepting that your state of affairs
shall be distinctive in scope and thus resisting the pull of the ‘cargo cult’: Specializing in
empathy, autonomy and features of communication that allow the structure on the
similar time, then there’s each purpose you can replicate the successes we’ve