How I Built It: $15K/month Mobile App
Starter Story
Jun 21, 2025
This is how Sebastian Röhl built a mobile app to $15K MRR
Complete your LLC filing today → https://go.starterstory.com/zenbusiness
Learn how to build mobile apps → http://build.starterstory.com/build/ios-bootcamp?utm_source=youtube&utm_campaign=sebastian
Follow Sebastian: https://x.com/SebastianRoehl
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Chapters:
0:00 - Intro
1:05 - Who is Sebastian
1:49 - Numbers behind HabitKit
2:15 - Building HabitKit
3:30 - Sebastian’s background
5:26 - Launch your LLC the right way
6:36 - Growing HabitKit
7:39 - App Store Optimization
8:40 - How to find and validate ideas
9:22 - Tech stack
10:36 - Cost to run the business
11:15 - Biggest lessons
11:53 - Advice
12:58 - Final Word
Chapters
Stack
Transcript
Chapters
Stack
No tools listed for this business.
I
turned
a
simple
habit
tracker
into
a
15K
MRR
business
Sebastian
Rolle
always
wanted
to
build
his
own
apps
So
he
decided
to
quit
his
job
and
give
himself
12
months
to
figure
it
out
No
plan
no
idea
just
a
dream
to
build
I
quit
my
job
with
no
idea
just
12
months
of
one
way
But
six
months
in
he
had
less
than
a
dozen
downloads
on
his
app
and
he
was
faced
with
a
decision
He
changed
up
his
strategy
and
then
found
an
idea
that
changed
everything
And
then
in
under
two
years
he
went
from
just
building
side
projects
that
made
him
a
few
hundred
bucks
to
a
full
time
solo
developer
making
15
000
a
month
on
the
App
Store
The
secret
to
reaching
top
10
in
the
App
Store
is
In
this
video
I
bring
Sebastian
onto
the
channel
to
break
down
what
happened
after
he
quit
his
job
and
it's
not
what
you'd
expect
We'll
also
go
over
his
failed
ideas
and
why
they
didn't
work
And
he'll
share
the
secret
to
why
his
app
has
been
downloaded
over
300
000
times
This
is
the
playbook
to
building
successful
apps
I'm
Pat
Walls
and
this
is
Starter
Story
Welcome
Sebastian
to
Starter
Story
Thanks
for
coming
on
So
tell
me
what's
your
story
Hi
thank
you
for
having
me
My
name
is
Sebastian
I
am
32
years
old
I'm
living
in
Germany
and
yeah
I'm
the
creator
of
HabitKit
It's
a
visually
appealing
and
very
simple
habit
tracking
mobile
app
that
helps
users
build
and
maintain
their
daily
habits
I
launched
HabitKit
in
2022
after
I
quit
my
corporate
programming
job
to
finally
become
a
full
time
indie
app
developer
Since
then
my
app
has
grown
significantly
reaching
15
000
in
monthly
recurring
revenue
through
a
combination
of
building
in
public
and
effective
App
Store
optimization
Beautiful
okay
Well
let's
dive
a
little
bit
more
into
this
business
and
some
of
the
numbers
behind
it
I
have
roughly
300
000
downloads
on
the
App
Store
Store
and
Google
Play
combined
and
over
2000
reviews
and
ratings
I'm
ranking
for
various
important
keywords
in
the
habit
tracking
space
The
most
important
one
is
Habit
Tracker
in
the
top
five
in
multiple
countries
for
that
I
love
that
Let's
go
right
into
development
of
the
app
I
know
that
you
have
a
software
development
background
Tell
me
about
how
you
built
this
app
Yeah
sure
I
had
that
idea
for
HabitKit
in
summer
of
2022
I
immediately
started
building
the
app
and
I
used
Flutter
for
this
That's
a
cross
platform
framework
that
allows
you
to
deploy
your
apps
to
iOS
and
Android
with
a
single
code
base
When
I
started
I
focused
on
the
core
functionality
which
was
a
tile
based
grid
chart
for
the
user's
habits
habits
with
a
clean
and
super
simple
interface
and
the
MVP
features
just
included
the
basic
habit
tracking
and
the
visualization
of
the
progress
And
I
built
it
with
privacy
in
mind
All
data
is
stored
locally
on
the
device
There's
no
sign
in
required
no
authentication
The
users
have
complete
control
over
their
data
I
also
decided
to
share
the
development
progress
on
my
social
media
And
after
posting
the
first
screenshots
and
seeing
a
positive
reception
I
knew
that
I
should
really
hurry
up
and
bring
the
app
to
the
app
store
and
make
it
quick
I
kept
it
really
simple
and
clean
and
just
banged
it
out
in
two
months
So
let's
take
a
step
back
and
I
wanna
learn
a
little
bit
more
about
your
past
your
background
What
were
you
doing
before
this
And
how
did
that
lead
to
coming
up
with
the
idea
for
HabitKit
Yeah
so
my
background
is
pretty
straightforward
After
school
I
studied
computer
science
at
a
university
here
in
Germany
for
roughly
six
years
and
did
my
master's
thesis
And
after
that
I
started
a
regular
programming
job
at
a
middle
sized
company
here
in
Germany
as
well
I
learned
a
lot
there
but
after
three
years
of
being
stuck
in
the
same
project
there
I
became
a
little
bit
restless
and
wanted
to
be
a
little
bit
creative
and
work
on
my
own
projects
So
after
three
years
of
the
same
project
at
my
regular
job
I
decided
it
was
time
to
quit
my
job
and
focus
on
indie
development
for
at
least
12
months
The
first
six
months
were
really
challenging
I
didn't
had
a
lot
of
revenue
so
I
kept
in
touch
with
the
people
at
my
old
job
And
after
my
12
month
deadline
was
over
I
decided
to
go
back
to
my
old
job
and
continue
doing
my
app
business
on
the
side
I
felt
like
a
failure
and
like
a
success
success
because
I
had
at
least
some
revenue
It
wasn't
really
high
but
I
think
it's
already
a
huge
success
if
you
have
a
side
business
with
1
000
revenue
At
the
end
of
2023
I
finally
reached
3
000
in
monthly
recurring
revenue
At
the
end
of
2024
achieved
over
15
000
in
MRR
I
quit
my
job
the
second
time
at
the
start
of
2024
And
I'm
finally
able
to
have
complete
control
over
my
time
and
work
on
whatever
I
want
All
right
before
we
dive
into
how
Sebastian
built
his
app
to
over
300
000
downloads
let's
talk
about
something
that
trips
up
way
too
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founders
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You
spend
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marketing
growing
but
if
you're
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or
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one
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That's
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Now
let's
get
back
to
Sebastian's
story
I
wanna
get
a
little
bit
more
tactical
How
did
you
actually
grow
this
business
and
what
marketing
channels
did
you
use
for
HabitKit
In
the
beginning
building
in
public
was
huge
for
me
I
shared
my
journey
and
development
process
across
multiple
platforms
like
X
LinkedIn
Blue
Sky
and
Threads
I
tried
to
create
authentic
content
share
about
my
wins
failures
successes
and
so
on
that
led
to
unexpected
opportunities
being
guests
on
podcasts
being
featured
on
videos
or
having
good
connections
to
other
app
developers
So
that
was
a
huge
part
of
my
success
in
the
beginning
Another
important
aspect
are
search
ads
I
just
I
won
a
super
simple
and
low
budget
Apple
search
ads
campaign
I
only
spent
100
per
month
on
it
I
just
used
this
as
a
potential
ranking
boost
strategy
because
I
have
the
hope
that
Apple
favors
developers
who
also
won
ads
on
their
platform
And
after
that
the
biggest
thing
probably
was
app
store
optimization
App
store
optimization
is
basically
editing
your
app
store
metadata
like
keywords
app
name
or
subtitle
or
even
the
screenshots
in
the
way
that
you're
more
likely
to
rank
in
the
top
spots
when
people
search
for
certain
keywords
I'm
focusing
on
the
habit
tracker
keyword
and
that's
why
I
put
it
right
at
the
start
of
my
app
name
Another
important
aspect
of
ASO
is
gathering
user
reviews
for
your
app
I
instantly
show
the
native
review
dialogue
So
it
says
do
you
like
HabitKits
Please
review
it
on
the
app
store
or
something
like
that
Right
after
the
first
habit
was
checked
off
for
a
user
So
that's
their
first
success
moment
And
I
asked
them
right
at
the
situation
And
most
people
just
give
it
five
stars
and
you
gain
a
lot
of
reviews
and
ratings
Yeah
so
gathering
reviews
is
pretty
important
Let's
talk
about
ideas
You've
launched
a
few
things
on
the
app
store
Some
of
them
were
flops
Some
of
them
are
hugely
successful
Tell
me
about
your
process
for
finding
ideas
and
validating
them
In
terms
of
finding
good
ideas
my
recommendation
is
to
just
start
building
anything
It
doesn't
matter
what
exactly
Once
you
get
into
the
groove
and
start
building
something
you
will
naturally
get
a
ton
of
other
great
cool
ideas
for
later
projects
In
terms
of
validation
I
just
build
apps
that
solve
my
own
problems
I
will
always
be
my
first
customer
And
so
I
always
know
exactly
what's
needed
in
the
product
what
are
the
requirements
and
what
works
and
whatnot
Cool
I
love
that
So
you
have
an
app
that
makes
15
000
a
month
month
Walk
me
through
the
different
technologies
and
stack
that
you
use
to
actually
build
this
app
In
terms
of
development
tools
I
use
Flutter
That's
a
cross
platform
framework
for
building
mobile
apps
for
iOS
and
Android
with
a
single
code
base
I
use
Cursor
as
my
AI
powered
IDE
I
love
the
auto
completions
that
the
AI
provides
and
I
love
to
chat
about
different
problems
with
it
To
do
my
keyword
research
and
ASO
optimizations
I
used
a
tool
called
Astro
It
allows
you
to
search
for
keywords
on
the
App
Store
Store
and
see
their
popularity
and
difficulty
For
app
analytics
and
marketing
and
also
a
little
bit
of
keyword
research
I
use
AppFigures
And
in
terms
of
handling
subscriptions
and
purchases
in
my
apps
I
use
a
service
called
Revenue
Cat
Yeah
and
for
personal
habit
tracking
I
use
HabitKit
of
course
I
also
use
some
other
tools
like
Waycast
which
is
a
collection
of
productivity
tools
for
your
Mac
and
Chat
with
AI
1Password
These
are
some
very
important
tools
in
my
tool
chain
Okay
cool
On
a
similar
note
let's
talk
about
costs
I
know
you're
a
solopreneur
You're
running
this
yourself
You
built
everything
out
You
don't
have
any
employees
How
much
does
it
actually
cost
in
total
to
run
an
app
like
this
Yeah
so
my
expenses
are
super
low
My
biggest
expense
is
Revenue
Cat
right
now
because
they
take
1
of
my
revenue
So
depending
on
the
month
of
the
year
that
can
be
a
lot
but
it's
totally
worth
it
And
yeah
the
rest
can
be
added
up
to
roughly
200
or
300
per
month
So
it's
really
low
Nice
wow
Okay
cool
So
your
app
makes
15
000
a
month
month
You've
kind
of
gone
through
the
process
of
building
something
successful
What
is
something
that
you
learned
in
the
process
that
you
didn't
expect
Yeah
I
was
super
surprised
that
I
was
able
to
compete
in
the
App
Store
and
Google
Play
with
bigger
companies
or
people
that
are
super
long
on
the
App
Store
I
reached
top
five
in
super
important
keywords
which
drives
a
ton
of
organic
traffic
to
my
apps
And
yeah
if
you
manage
to
secure
a
good
ranking
on
the
App
Store
you
don't
need
a
big
marketing
budget
and
you
can
compete
with
bigger
brands
Nice
cool
Well
the
last
question
that
we
ask
all
founders
that
come
on
Starter
Story
if
you
could
go
back
in
time
and
give
advice
to
Sebastian
right
when
he
quit
his
job
what
advice
would
you
give
I
would
say
save
money
for
sabbatical
to
focus
on
development
of
your
app
business
like
I
did
I
saved
some
money
and
I
just
quit
my
job
and
set
myself
a
deadline
for
12
months
to
do
something
that
works
Yeah
because
I
couldn't
find
motivation
to
code
on
my
own
apps
after
I
programmed
for
eight
hours
on
my
regular
job
So
quitting
my
job
was
actually
the
only
chance
to
get
this
started
And
yeah
this
ultimately
helped
me
to
focus
on
my
stuff
and
lay
the
important
foundation
and
ultimately
for
my
dream
business
Yeah
I
love
that
You
know
a
lot
of
people
think
what's
gonna
happen
if
I
quit
my
job
But
at
the
end
of
the
day
you
can
just
go
back
and
get
another
job
and
that's
exactly
what
happened
to
you
And
I
just
love
this
story
Thank
you
for
coming
on
Sebastian
and
sharing
everything
about
your
business
going
deep
sharing
a
bunch
of
things
that
you
didn't
have
to
You're
awesome
Thanks
for
coming
on
Starter
Story
Thank
you
for
having
me
All
right
I
love
Sebastian's
story
It
shows
you
the
power
of
building
on
platforms
We
talked
all
about
ASO
which
I
think
is
super
cool
So
hopefully
that
was
helpful
If
you
wanna
build
something
similar
to
Sebastian
check
out
Starter
Story
Build
It
is
our
platform
for
building
a
real
app
going
from
an
idea
to
a
launched
app
in
12
days
I'll
put
that
link
in
the
description
Thank
you
guys
for
watching
I'll
leave
you
with
one
question
What's
your
story
Peace
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