Linking Modular Structure to Growth Groups

This text will exhibit 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. Inside characteristic disparity arising from a scarcity of compatibility/reusability
    between in-house
    market apps

This text charts the journey one among our shoppers took when making an attempt to deal with these
points. We inform the story of how their organisation had prior to now, gravitated in direction of
appropriate options, however was not in a position to see the anticipated advantages because of a
misunderstanding of how these options have been intrinsically

We develop this statement by recounting how the identical organisation was in a position to 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 crew topologies to match a
modular structure whereas on the identical time, investing within the developer

Recognising the Indicators

Regardless of the most effective of intentions, software program usually deteriorates over time, each in
high quality and efficiency. Options take longer to get to market, service outages
change into extra extreme and take longer to resolve, with the frequent consequence that these
engaged on the product change into annoyed and disenfranchised. A few of this may be
attributed to code and its upkeep. Nevertheless, putting the blame solely on code
high quality feels naive for what’s a multifaceted concern. Deterioration tends to develop
over time by means of a fancy interaction of product selections, Conway’s regulation, 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 accurately attributed the friction they have been
experiencing to elevated complexity as their app grew- their present growth
crew struggled so as to add options that remained coherent and according to the
present 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 turned
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 needs to be sufficiently small to be fed by two
pizzas. The idea goes that by limiting how huge a crew can change into, you keep away from the
scenario the place communication administration takes extra time than precise worth creation.
That is sound idea and has served Amazon nicely. Nevertheless, when contemplating an
present crew that has merely grown too huge, there’s a tendency in 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
change into more and more profitable however was additionally unable to copy the required fee of
success because it grew in options, duties and crew members. With looming
characteristic supply deadlines and the prospect of a number of model markets on the
horizon, they responded by splitting their present groups into a number of smaller,
related sub-squads – every crew remoted, managing a person market (regardless of
related buyer journeys).

This in actual fact, 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 rising period of time from these tasked with precise worth creation, our
preliminary suggestion concerned the concept of ‘cognitive
outlined by Skelton & Pais (2019). This includes 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
all the way down to a single shared focus. This was in idea an awesome resolution to our shopper’s
drawback, however can really be deceptive when thought of 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 beneficial for organising advanced logic into manageable teams
and defining a standard language or mannequin for every. Nevertheless, breaking up an
utility into domains is simply a part of an ongoing course of. Holding tight management
of the
bounded context
is as necessary as defining the domains themselves.
Inspecting our shopper’s utility’s code we encountered the frequent lure of a transparent
preliminary funding defining and organising area duties accurately, solely
to have began to erode that self-discipline because the app grew. Anecdotal proof from
stakeholders urged that perpetually busy groups taking shortcuts pushed by
pressing product
necessities had change 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 4
Key Metrics
because it turned harder to launch code and more durable to debug

Additional warning indicators of a poorly managed bounded context have been found by means of
frequent code evaluation instruments. We discovered a codebase that had grown to change into tightly
coupled and missing in cohesion. Extremely
is tough to vary with out affecting different elements of your system.
Code with low cohesion has many duties and considerations that don’t match inside
its remit, making it obscure its goal. Each these points had been
exacerbated over time because the complexity of every area inside our shopper’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 seemingly involuntarily have an effect on others. We seen that
due to this, growth groups wanted data of a number of domains to resolve
something that may break, rising 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 adjustments, 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’ may very well be rejected or rectified earlier than they might develop

One other metric that was lacking from the organisation’s cell functions was optionality
of reuse
. As talked about earlier, there have been a number of present, mature model
market functions. Function parity throughout these functions was low and a
willingness to unify right into a single cell app was tough because of a need for
particular person market autonomy. Tight coupling throughout the system had lowered the power
to reuse domains elsewhere: Having to transplant most of an present 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 would have liked to take.

Domains that Transcend Apps

State of affairs 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 characteristic request
to a person utility:

characteristic request is handed to the app squads that personal the related area. Our
bounded context signifies that the blast radius of our change is contained inside
itself, that means our characteristic could 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 characteristic disparity arising
from a scarcity of reusability
– we began to run into issues.

State of affairs 2 – ‘The Subsequent Market Alternative’

The following 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 present market utility. This concerned the creation of a standard
framework (points 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 beneath reveals two market
functions, one within the UK, the opposite, a brand new app primarily based out of the US. Our US
primarily based 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 direction of modularity, we had did not have in mind the present
communication constructions of the organisation that finally dictated the
precedence of labor. Creating our earlier instance as a way to elucidate: After
utilizing the domains in their very own market the US crew had an thought for a brand new characteristic
in one among 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 characteristic request. The
UK crew accepts the request and maintains that it appears like “an awesome thought”,
solely they’re presently “coping with requests from UK primarily based stakeholders”
so it is unclear when they may have the ability 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 turning into annoyed on the lack of progress
from imported domains. We theorized quite a few 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
total area so as to add a small quantity of performance is inefficient, and
diverging additionally creates issues for any future sharing of upgrades or characteristic
parity between markets. An alternative choice we appeared 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 assist 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 characteristic growth to offer architectural steering or PR opinions.

State of affairs 3 – ‘Market Agnostic Domains’

Clearly the issue lay with how our groups have been organised. Conway’s
is the statement that an organisation will design its enterprise
techniques to reflect its personal communication construction. Our earlier examples
describe a state of affairs 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 includes altering the construction of growth groups
in order that they allow the chosen technical structure to emerge.

Within the beneath instance we advance from our earlier state of affairs and make the
structural adjustments to our groups to reflect the modular structure we had
beforehand. Domains are abstracted from a particular cell app and as a substitute are
autonomous growth groups themselves. After we did this, we seen
relationships modified between the app groups as they now not had a dependency
on performance between markets. Of their place we discovered new relationships
forming that have been higher described by way of shopper and supplier. Our area
groups offered the performance to their market prospects who in flip consumed
them and fed again new characteristic requests to raised 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 website originating from inside
one other market. Abstracting a website from its market modified the main target 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 turned measured each in shopper uptake and the way it was
acquired by the tip consumer. Any new performance was reviewed solely on the
quantity of worth it dropped at the area and its customers total.

Concentrate on Developer Expertise to Assist Modularity

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

In follow,
nevertheless, we discovered that these are tough technical issues to resolve. For instance,
do you preserve a degree of UX/model consistency throughout autonomous area groups? How
you allow cell app growth when you’re solely liable for a part of an
utility? How do you permit discoverability of domains? Testability? Compatibility
throughout markets? Fixing these issues is totally 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 Resolve 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 throughout the chosen structure.
Our new area crew maintains the supplier/shopper relationship we now have seen
already, and is liable for bettering the developer expertise for groups
that construct their apps and domains throughout 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
necessary to outline what was required for our new crew to ship a great one. We
granularised the DX area all the way down to a set of essential 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 lowering the friction felt
when onboarding. Some examples we outlined for our platform area:

We Promise that:

  • It is possible for you to to shortly 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

Word that these guarantees describe components of a self-service expertise inside a
developer productiveness platform. We subsequently noticed an efficient
as one which allowed groups that have been targeted round end-user
performance to focus on their mission fairly than combating their method
by means of a seemingly countless listing of unproductive

The second essential functionality we recognized for the platform area was Technical
Structure as a Service
. Within the organisation, architectural capabilities additionally
adopted Conway’s regulation and because of this the accountability for structure
selections was concentrated in a separate silo, disconnected from the groups
needing the steering. Our autonomous groups, whereas in a position to make their very own
selections, tended to want some facet of ‘technical shepherding’ to align on
rules, 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 most effective follow we offer will likely be accompanied
    with examples that you would be able to
    use or precise steps you may take
  • we’ll preserve an total
    image of area utilization per app and when wanted,
    orchestrate collaboration throughout verticals
  • The trail to
    manufacturing will likely be seen and proper
  • We’ll work with you”

Word that these guarantees describe a servant
relationship to the groups, recognizing that everybody is
liable for the structure. That is in distinction to what some may
describe as command and management architectural governance insurance policies.

One final level on the Platform Area, and one value 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 thought being that by visiting the supply of the
drawback and seeing it for your self, solely then can you understand how to repair it. We
realized {that a} crew with the main target of bettering developer expertise should be
in a position to empathise with builders that use their product to actually perceive
their wants. After we first created the platform crew, we didn’t give this
precept the main target it deserved, solely to see our autonomous groups discover their very own
method. This finally induced duplication of efforts, incompatibilities and a scarcity
of perception within the structure that took time to rectify.

The Outcomes

We’ve instructed the story about how we modularised a cell app, however how profitable was it
over time? Acquiring empirical proof could be tough. In our expertise, having
a legacy app and a newly architected app throughout the identical organisation utilizing the identical
domains with supply metrics for each is a state of affairs 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 examine 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 efficient 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 kind has no bearing on.

Cell 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
important uplift versus the Legacy App with a much less skilled crew.

Our second comparability considerations optionality of re-use, or lack thereof. On this
state of affairs we study the identical two cell apps within the organisation. Once more, we examine
one requiring present area performance (with no alternative however to jot down it
themselves) with our modular app (in a position to plug and play an present area). We
ignore the frequent steps on the trail to manufacturing since they don’t have any affect on what
we’re measuring. As a substitute, we deal with the points throughout the management of the
growth crew and measure our growth course of from pre-production ‘product
log off’ 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 facility of a modular structure in
a setting that has a enterprise want for it.

As an apart, it’s value mentioning that these exterior components we now have excluded
also needs to be measured. Optimising your growth efficiency might 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 could be improved to five
days, and it nonetheless takes 1 month to approve, then compliance
might change into the subsequent bottleneck to optimise.

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

We found two concentric suggestions loops which affect the speed of adoption. The
outer, a great integration expertise from the buyer 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 inside, a great finish consumer expertise – how nicely
the general journey (together with the built-in area) is acquired by the buyer’s
market buyer. A poor shopper expertise impacts adoption and finally dangers
insulating the area crew from the precise customers of the potential. 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 have been the
most profitable.

The ultimate comparability value 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 price 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 – bettering 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
value taking into consideration the restrictions of those approaches. Firstly, and certainly most
importantly, an architectural shift similar to this takes a variety of ongoing time and
. It ought to solely be used to resolve severe present enterprise issues
round velocity to market. Secondly, giving autonomy to area groups could be each a
blessing and a curse. Our platform squad can present frequent implementations within the
type of smart defaults however finally the alternatives are with the groups themselves.
Naturally, coalescing on platform necessities similar 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 inner dependencies or eclectic
is difficult. Ignoring this drawback and permitting the general app to
develop uncontrolled is a recipe for poor efficiency within the arms of the client.
Once more, we discovered that funding in technical management, along with sturdy
guardrails and pointers helps to mitigate this drawback by offering
structure/design oversight, steering and above all communication.


To recap, firstly of this text we recognized two important 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 rising
disparity between different related in home functions
. 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 points. We began by demonstrating how evolving crew
constructions to assist 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 regulation inherent with
an utility monolith. We noticed that this alteration 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 points collectively, we have been in a position to exhibit a 60% discount in
cycle time
averaged throughout all modular domains in a market utility. We additionally
noticed an 18 fold enchancment in growth price when integrating modular
domains to a market app fairly 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 new domains and the continued assist the ‘platform crew’
offered. In real-terms for our shopper, these financial savings meant with the ability to capitalise
on market alternatives that have been beforehand thought of far too low in ROI to
justify the hassle – 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 could be
extremely helpful to an organisation underneath the fitting circumstances. Whereas the
outcomes from our time with the highlighted organisation have been glorious, they have been
particular to this particular person case. Take time to know 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 deliver an ecosystem like
that which we now have described collectively. An in poor health thought of effort will greater than
seemingly trigger extra issues than it solves. However, by accepting that your scenario
will likely 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
identical time, then there’s each cause you possibly can replicate the successes we now have

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