How I Built It: $400K/Month Mobile App (Gravl)
Starter Story
Nov 13, 2025
Julian Gargicevich discovered a fitness app that was crushing it, but when he tried it, he thought: " Maybe I can build something better." He built his MVP in 2 months, posted it on Reddit, and his app had almost immediate product-market fit. Now his team is at $400K/month with 70K+ subscribers.
End AI Analysis Paralysis → https://clickhubspot.com/4d74f4
Build your own app with AI→ https://build.starterstory.com/build/ai-build-accelerator?utm_source=youtube&utm_campaign=juliangravl
Follow Julian on X: https://x.com/julian_gargi
🔔 Follow the Second Channel: @StarterStoryBuild
🏁 We're hiring: starterstory.com/jobs
Chapters:
0:00 - Intro
1:09 - Julian's background
2:51 - How he found the idea
4:01 - Building the MVP
4:48 - His first 1,000 customers
5:45 - Learn about AI from the experts
6:55 - Marketing strategy breakdown
7:46 - 5 tips for building mobile apps
9:31 - How the app works (full walkthrough)
12:11- Mobile app teck stack
12:37 - Costs & Margins
13:54 - "Be proud of what you build"
14:55 - Final word
This video is an educational case study of one founder’s experience. It is not financial advice and does not guarantee any income or results. Every business is different and your results may vary.
Chapters
Stack
Transcript
Chapters
Stack
No tools listed for this business.
Last
month
we
made
over
440k
Meet
Julian
a
developer
from
Argentina
who
built
an
app
that
makes
over
400
000
a
month
But
it
didn't
start
that
way
Before
the
success
Julian
was
a
dude
at
the
gym
who
discovered
a
different
app
that
he
thought
was
pretty
cool
However
instead
of
just
using
it
himself
he
thought
what
if
I
built
something
better
And
that's
exactly
what
he
did
He
built
an
MVP
posted
about
it
on
Reddit
and
the
rest
is
history
I
posted
this
thread
on
how
I
We
got
our
first
couple
thousand
users
I
can't
really
remember
but
it
was
a
lot
That
was
the
biggest
high
probably
I've
ever
had
I
brought
Julian
onto
the
channel
to
break
down
this
story
and
how
he
actually
built
an
app
app
used
by
hundreds
of
thousands
of
people
In
this
episode
we'll
dive
into
the
original
app
he
cloned
in
just
two
months
the
simple
Reddit
strategy
that
got
him
his
first
users
and
product
market
fit
and
the
marketing
playbook
that
scaled
his
app
to
over
400
000
a
month
Let's
dive
in
I'm
Pat
Walls
and
this
is
Starter
Story
All
right
Julian
welcome
to
the
channel
Tell
me
about
who
you
are
what
you
built
and
what's
your
story
Hey
Pat
I'm
Julian
I'm
one
of
the
co
founders
and
developer
of
Gravel
an
AI
fitness
app
that
provides
smart
workouts
for
the
gym
We
launched
around
two
years
ago
and
now
we
have
over
70
000
subscribers
Last
month
we
made
over
440
000
Okay
over
400
000
with
an
app
is
insane
We're
going
to
get
all
into
that
but
before
we
do
I
want
to
understand
a
little
bit
more
about
your
background
How
do
you
even
get
into
building
an
app
I
grew
up
in
Argentina
My
dad
used
to
own
a
fitness
center
I
pretty
much
spent
all
my
time
just
playing
sports
and
at
the
gym
I
then
got
into
software
engineering
and
moved
to
Australia
Here
I
worked
from
small
startups
to
big
tech
companies
like
Atlassian
a
few
TV
channels
even
an
investment
fund
Around
COVID
my
best
friend
and
also
our
partner
came
up
with
the
idea
of
starting
a
company
It
was
like
an
ad
start
an
influencer
marketing
platform
for
mobile
games
That's
how
we
started
Fast
forward
a
couple
of
years
we
ended
up
being
some
sort
of
a
marketing
agency
which
was
something
that
I
didn't
sign
up
for
neither
did
the
guys
but
the
good
thing
is
that
we
learned
a
lot
about
user
acquisition
and
marketing
but
also
what
the
numbers
were
so
in
terms
of
revenue
After
seeing
some
of
those
numbers
we
obviously
thought
apps
make
a
lot
of
money
and
especially
fitness
apps
so
we
kind
of
used
our
background
to
decide
that
we
wanted
to
start
our
own
app
You
had
this
business
You
started
with
partners
It
wasn't
really
what
you
wanted
to
build
Maybe
it
wasn't
fully
scalable
How
does
that
turn
into
building
an
app
that
now
makes
over
400
000
a
month
The
business
wasn't
doing
great
and
because
we
transitioned
into
this
kind
of
agency
format
I
had
all
this
energy
for
developing
something
that
wasn't
being
used
so
I
started
with
more
like
a
workout
tracker
kind
of
app
so
apps
like
that
kind
of
thing
but
as
I
was
building
it
I
noticed
that
okay
I'm
not
adding
any
value
It
just
felt
like
a
copy
of
what
they
were
doing
and
then
it
was
one
of
my
mates
He
showed
me
Fitbot
and
Fitbot
is
one
of
the
biggest
workout
apps
and
when
he
showed
me
the
app
I
was
like
this
is
amazing
because
it
kind
of
provided
you
with
workouts
on
the
spot
and
you
didn't
really
have
to
do
anything
else
but
then
I
started
using
it
and
doing
some
research
I
noticed
that
workouts
were
weird
and
even
a
bit
dangerous
sometimes
and
the
more
I
used
it
I
was
like
wow
okay
these
workouts
are
actually
bad
That's
what
triggered
me
and
then
I
was
like
okay
this
is
it
We
need
to
build
Fitbot
UI
UX
with
an
actual
proper
workout
engine
That's
kind
of
when
we
went
all
in
on
building
it
Can
you
tell
me
a
little
bit
more
about
how
you
built
it
how
long
it
took
Initial
MVP
took
around
two
to
three
months
maybe
We
can
split
the
MVP
into
two
parts
first
part
being
pre
Fitbot
and
then
after
Fitbot
The
first
part
of
the
MVP
was
more
of
the
tracker
Then
we
transitioned
into
the
Fitbot
stuff
and
that's
when
things
got
tricky
There's
a
lot
of
business
logic
around
building
custom
workouts
for
people
There's
just
a
lot
of
settings
and
combinations
things
like
equipment
things
like
your
weekly
goal
how
often
do
you
go
to
the
gym
are
you
consistent
your
gender
your
weight
your
age
There's
just
so
many
things
to
consider
That
was
definitely
the
most
challenging
part
Tell
me
about
how
you
launched
this
how
you
got
your
first
customer
What
did
you
do
to
get
this
app
off
the
ground
and
get
into
people's
hands
I'm
a
massive
supporter
of
Reddit
as
a
distribution
channel
I
posted
this
thread
on
how
I
build
gravel
Back
in
the
day
it
was
called
Gainz
AI
and
I
shared
kind
of
the
technical
specs
around
it
It
got
over
a
couple
hundred
likes
within
the
first
couple
hours
and
over
300
000
impressions
We
got
our
first
couple
thousand
users
I
can't
really
remember
but
it
was
a
lot
We
found
out
that
because
they're
developers
and
they
like
tech
and
some
of
them
might
like
going
to
the
gym
but
they
feel
like
it's
a
bit
intimidating
I
feel
like
a
lot
of
them
were
actually
using
the
app
and
then
we
started
getting
feedback
about
bugs
and
feature
requests
and
we're
like
okay
we're
onto
something
That
was
the
final
push
that
we
needed
because
at
this
point
the
app
was
free
and
we're
like
okay
now
we
need
to
build
a
serious
business
out
of
this
and
try
to
start
running
some
apps
for
it
Okay
let's
talk
about
something
that
is
changing
the
game
for
builders
right
now
AI
Now
I
know
we
talk
about
AI
apps
a
lot
on
this
channel
but
I
still
get
this
question
every
day
from
builders
Where
do
I
even
start
That's
where
HubSpot
for
Startups
AI
Adoption
Playbook
comes
in
handy
It's
a
free
guide
with
a
three
step
framework
on
how
to
use
AI
inside
your
business
Inside
you'll
learn
how
to
spot
AI
opportunities
in
your
workflow
implement
AI
without
hiring
expensive
consultants
and
see
the
exact
playbooks
companies
are
using
to
get
real
results
What's
even
cooler
is
it's
from
executives
at
HubSpot
Anthropic
and
Repl
it
some
of
the
biggest
AI
companies
in
the
world
right
now
My
favorite
part
is
inside
the
case
studies
where
you
will
see
exactly
how
one
company
booked
11
000
meetings
and
another
resolved
customer
issues
39
faster
using
this
framework
These
are
real
numbers
from
real
businesses
So
if
you're
ready
to
get
ahead
in
the
AI
race
download
HubSpot
for
Startups
free
AI
Adoption
Playbook
at
the
first
link
in
the
description
below
Thank
you
to
HubSpot
for
sponsoring
this
video
Let's
get
back
into
it
I'm
sure
that
probably
isn't
what
got
you
to
over
400
000
a
month
So
what
has
been
the
actual
distribution
strategy
or
the
secret
sauce
behind
Gravel
on
how
it
grew
to
over
4
million
a
year
For
us
bigger
distribution
was
paid
ads
We
started
running
ads
as
soon
as
we
obviously
added
the
subscription
model
I
still
remember
running
our
first
ad
we
got
a
subscription
within
the
first
10
minutes
of
activating
the
ads
Yeah
that
was
the
biggest
high
probably
I've
ever
had
And
after
that
we
translated
the
app
to
Spanish
We
started
running
ads
on
South
America
and
we
were
spending
less
than
50
bucks
a
day
on
ads
And
that's
what
worked
for
us
from
the
start
up
until
this
day
The
next
question
I
have
for
you
that
I'm
curious
about
is
you
built
this
app
It's
huge
It's
doing
over
400
000
a
month
What
would
be
your
top
learnings
or
top
tips
for
anyone
building
apps
in
2025
specifically
consumer
apps
or
even
fitness
specific
Tip
number
one
for
sure
will
be
to
validate
before
spending
money
on
ads
And
when
I
say
validate
it's
not
just
that
the
product
works
but
also
that
people
are
willing
to
pay
for
it
That's
also
something
very
important
Tip
number
two
would
be
and
this
is
where
we
kind
of
got
lucky
because
well
I'm
Spanish
speaking
and
Matias
as
well
So
it
makes
sense
for
us
to
translate
it
into
Spanish
and
then
potentially
running
ads
that
are
cheaper
in
South
America
The
US
even
though
we
all
want
to
end
up
there
and
running
ads
there
it's
expensive
There's
a
lot
of
competition
Tip
three
is
start
small
You
can
pay
influencers
or
content
creators
as
low
as
50
bucks
for
some
content
You
can
use
AI
tool
to
create
videos
You
can
use
CapCut
to
edit
your
own
videos
and
you
can
get
some
pretty
good
results
with
that
It's
not
as
hard
as
you
think
to
create
an
ad
The
hard
thing
is
creating
the
volume
And
tip
four
like
I
said
UGC
is
king
You'll
see
that
most
of
the
ads
ads
that
work
out
there
are
UGC
content
You're
seeing
a
lot
of
AI
videos
and
that's
cost
of
and
they're
easy
to
test
Last
thing
would
be
copy
copy
and
copy
Good
thing
about
Meta
Ads
Library
is
that
it's
all
public
You
can
go
into
any
of
your
competitions
dashboard
and
see
which
ads
are
working
for
them
where
they're
putting
more
money
And
yeah
there's
no
secret
sauce
there
Just
copy
what
works
for
them
and
start
like
that
It'll
probably
work
for
you
I
would
definitely
start
there
Okay
cool
Well
those
tips
were
amazing
I'd
love
if
you
could
show
us
what
your
app
does
and
give
us
a
quick
demo
of
how
it
works
and
how
something
like
this
could
potentially
make
400
000
a
month
This
is
our
app
This
is
Gravel
We're
an
AI
fitness
app
specifically
designed
for
strength
training
and
gym
workouts
This
is
the
screen
you'll
see
when
you
first
download
the
app
So
this
is
our
landing
screen
We
get
your
name
and
then
we'll
just
go
and
ask
you
a
series
of
questions
like
why
do
you
want
to
use
a
fitness
app
We
ask
you
about
your
experience
Let's
say
I'm
an
advanced
user
Depending
on
your
level
we'll
ask
more
specific
questions
like
what's
your
one
rep
max
for
certain
exercises
your
goals
ask
you
about
your
training
frequency
your
working
split
We
use
AI
here
and
there
Make
sure
that
you
are
showing
the
users
that
this
is
an
AI
app
because
that
sells
now
Again
more
questions
specific
to
how
you
want
to
train
Excluded
muscles
and
focused
muscle
help
us
design
the
workout
towards
something
that
you
kind
of
like
Where
do
you
train
Because
like
I
said
we
adapt
to
your
gyms
and
anywhere
you
train
So
here
is
where
you
create
kind
of
that
gym
profile
This
kind
of
screen
where
we
generate
and
show
the
user
that
we're
generating
a
custom
workout
You
get
to
this
final
screen
where
you
get
your
plan
kind
of
summary
Here
we
go
Hard
pay
Well
before
you
sign
in
for
the
first
time
it's
like
how
many
users
are
actually
going
to
pay
before
they
actually
see
their
product
And
the
answer
is
a
lot
This
is
what
you
see
when
you
first
open
the
app
And
the
main
thing
is
the
workout
card
That's
the
main
thing
about
the
app
That's
90
of
your
flow
is
going
to
be
within
the
active
workout
Here
you
just
get
a
list
of
exercises
that
you
need
to
do
from
here
on
It's
like
kind
of
works
like
a
workout
tracker
We
have
proper
content
for
every
video
We
have
a
description
and
how
to
do
each
exercises
And
then
we
have
a
lot
of
smart
AI
features
Like
you
know
if
you
sort
exercises
the
weights
are
adjusted
based
on
the
order
that
they're
at
The
app
is
pretty
complete
in
terms
of
everything
you
need
to
do
at
the
gym
Also
things
like
recovery
rate
will
tell
you
how
tired
or
not
your
muscles
are
based
on
your
previous
workout
And
that
includes
external
workouts
from
Apple
Health
from
Strava
It
could
be
runs
It
could
be
anything
We'll
learn
from
that
and
we'll
adapt
your
workouts
accordingly
And
one
of
the
important
thing
that
we
grew
a
lot
with
this
and
that
was
our
support
So
we
have
a
24
7
support
chat
inside
the
app
And
that
includes
everything
from
articles
to
messages
And
we'll
have
someone
reply
an
actual
person
not
an
AI
That's
something
that
users
value
a
lot
That's
pretty
much
it
On
a
similar
note
I'm
curious
what's
your
tech
stack
How
did
you
build
this
app
We
use
React
Native
and
Expo
for
the
backend
I
did
NET
for
most
of
the
core
functionality
I've
also
used
Next
and
React
to
build
some
like
internal
admin
dashboards
in
terms
of
AI
So
I
try
to
stay
kind
of
niche
with
what
I
use
Cursor
a
lot
but
I'm
very
specific
which
files
to
touch
and
don't
let
the
AI
just
go
rogue
basically
Yeah
Hey
guys
Julian
here
with
a
little
Async
update
from
the
future
We
finished
recording
the
video
and
realized
that
we
didn't
really
go
into
numbers
and
financials
of
the
business
Obviously
very
important
for
you
to
know
And
I'm
also
happy
to
share
some
of
them
Our
expense
number
one
is
meta
and
TikTok
And
then
maybe
a
little
bit
of
Google
maybe
a
little
bit
of
Apple
search
I'd
say
a
third
is
somehow
accurate
A
third
of
our
revenue
that
is
This
doesn't
include
making
the
ads
but
just
the
cost
of
running
them
Expense
number
two
is
salaries
It
was
mainly
just
the
three
of
us
for
our
first
year
I
did
the
development
and
then
Matthias
and
Aaron
did
the
growth
and
ads
Since
then
we've
grown
the
team
team
to
probably
maybe
13
to
14
people
give
or
take
There's
some
like
part
times
there's
some
contractors
I'd
say
somewhere
between
50
and
80k
Obviously
let's
not
forget
the
15
from
Apple
Revenue
cut
it's
a
1
clip
from
revenue
as
well
We
have
MMPs
which
is
maybe
a
grand
a
month
And
then
in
terms
of
infrastructure
for
running
the
actual
app
like
servers
and
AI
builds
and
other
tools
I'd
say
around
a
grand
a
month
as
well
The
last
question
that
I
want
to
ask
you
and
what
we
ask
all
founders
who
come
on
Starter
Story
what
would
be
your
advice
to
anyone
watching
this
right
now
that
wants
to
build
something
Be
proud
of
what
you
build
because
at
least
for
me
the
motivation
that
comes
from
building
something
that
I'm
excited
about
can't
be
matched
by
anything
else
It's
always
easier
to
grind
and
work
for
0
when
you
love
what
you're
doing
Another
thing
would
be
to
keep
pushing
then
don't
give
up
too
soon
It's
a
long
road
so
building
it
is
just
not
even
half
of
it
Be
ready
to
do
all
the
hustling
of
the
Reddit
stuff
that
I
did
for
example
and
then
having
ads
that
don't
work
And
you're
going
to
get
some
punches
so
you
need
to
know
that
you
just
need
to
keep
going
And
in
saying
that
it's
also
knowing
when
to
give
up
actually
when
you're
like
all
right
this
product
doesn't
work
So
that's
also
a
very
important
thing
In
our
case
it
was
our
previous
startup
We
probably
dragged
that
for
an
extra
year
We
should
have
probably
called
it
days
like
way
earlier
Well
that's
great
advice
Thank
you
Julian
for
coming
onto
the
channel
Thank
you
Pat
Thanks
for
the
time
What
I
love
about
Julian's
story
is
his
app
is
crushing
it
It's
making
over
400
000
a
month
but
also
it's
something
he's
super
passionate
about
Julian
clearly
loves
fitness
and
working
out
And
how
cool
is
it
that
you
get
to
build
an
app
that
makes
hundreds
of
thousands
of
people's
lives
better
and
it's
something
that
you
love
too
That
is
exactly
why
we
launched
Starter
Story
Build
so
you
can
do
the
same
In
Starter
Story
Build
we
will
help
you
ship
your
idea
to
the
real
world
in
just
a
couple
of
weeks
as
long
as
you
are
ready
to
actually
launch
your
product
So
if
you
are
head
to
the
link
in
the
description
to
check
out
Starter
Story
Build
That's
it
for
this
episode
of
Starter
Story
Thank
you
guys
for
watching
I'll
see
you
in
the
next
one
Peace
Get Access To All Startup Data Right Now (it's free)
Join our free newsletter to get unlimited access to all startup data. We just need your email:
S
Starter Story
Want to discover ideas that
actually
make money?
Get our 5-minute email newsletter packed with business ideas and money-making opportunities, backed by real-life case studies.
It's free and read by 200,000+ founders
Please sign in.
Create A Password
Check your email for a link to sign in
Check your email
We've sent you an email with a link to sign in. Click the link in the email to access your account.
If there's a Starter Story account associated with that email you'll get an email with a link to automatically log in. The link will expire in 24 hours.
Your existing password still works, should you want to log in with it later.
S
Starter Story
Unlock the secrets to 7-figure online businesses
With Starter Story, you can see exactly how online businesses get to millions in revenue.
Dive into our database of 4,418 case studies & join our community of thousands of successful founders.
S
Starter Story
Get The Report
S
Starter Story
Build a business that changes your life, in less than 5 weeks.
Discover a proven system to find, validate, and build your $1M business idea—alongside a community that won't let you fail.
Our next sprint starts soon...