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From YouTube: Advanced Seaport Techniques
Description
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https://archive.devcon.org/archive/watch/6/advanced-seaport-techniques/index
Seaport is a marketplace protocol for buying and selling NFTs. While it powers OpenSea in a horizontal capacity, Seaport is open source and allows marketplaces to share a pool of liquidity – enabling project-specific, bespoke vertical marketplaces. Since launch, it’s helped spur innovation across emerging NFT verticals, including ENS names, in-game purchases, etc. This workshop will explore advanced techniques and use cases for the Seaport protocol.
Speaker(s): Zero Age
Track: Developer Infrastructure
Keywords: Seaport,Marketplace,EVM
Follow us: https://twitter.com/efdevcon, https://twitter.com/ethereum
Learn more about devcon: https://www.devcon.org/
Learn more about ethereum: https://ethereum.org/
Devcon is the Ethereum conference for developers, researchers, thinkers, and makers.
Devcon 6 was held in Bogotá, Colombia on Oct 11 - 14, 2022.
Devcon is organized and presented by the Ethereum Foundation, with the support of our sponsors. To find out more, please visit https://ethereum.foundation/
A
A
So
first
thing
to
understand
is
that
there
are
two
arrays
that
dictate
the
basics
of
A
C
Port
listing
or
offer.
The
first
is
the
offer
and
that's
all
of
the
items
native
tokens,
erc20
EOC,
721
1155,
but
you
the
offerer,
are
going
to
spend
then,
on
the
other
end,
you
have
the
consideration,
which
is
everything
that
you
or
others
are
going
to
get
back.
A
So
there's
also
this
idea
of
a
Zone
every
Seaport
order
has
an
optional
Zone
that
you
can
set
that's
a
contract
that
gives
a
thumbs
up
or
a
thumbs
down
on
whether
that
particular
order
is
still
valid.
There's
also
a
concept
of
a
conduit
which
is
a
it's
a
contract
that
you
can
approve
to
transfer
your
tokens.
So
you
set
your
approvals
on
the
Conduit
and
from
there
you
can
set
additional
marketplaces
or
contracts
on
that
conduit
support,
multiple
marketplaces
migrate
to
new
versions
of
Seaport,
so
on
so
forth.
A
So
when
you
it
comes
time
to
create
an
order
to
list
your
nft
the
primary
way
to
do
it
is
you
just
sign
an
off-chain
listing?
This
is
an
example
payload
that
you
would
see
in
metamask,
you're
gonna
have
to
pop
open
the
expanded
view
to
get
this
whole
thing,
but
it's
got
the
offer
array.
Consideration
array
start
time
end
time
zone
conduit,
then
another
method
you
can
use
to
create
an
order
is
to
call
this
function
validate,
and
that
means
you
don't
need
a
signature
at
all.
A
You
just
provide
the
order
and
it
gets
listed
on
chain
so
to
speak.
The
interesting
thing
about
both
signing
an
order
or
calling
validate
is
you
have
to
explicitly
cancel.
You
have
to
actually
call
and
tell
Seaport
I'm
no
longer
interested
in
filling
this
yeah
signatures
are
not
just
standard.
Ecdsa
they're
also
support
for
1271,
which
is
is
valid.
A
It
wants
to
update
the
order
based
on
a
price,
that's
coming
back
from
an
oracle,
or
maybe
it's
implementing
a
bonding
curve,
or
it's
a
pool
something
to
that
effect.
So
what
you
do
is,
instead
of
giving
the
signature
for
12.71,
you
actually
give
the
order
itself
then,
and
this
there's
a
trick.
You
can
do
here
where
you
can
actually
Supply
an
offset
to
call
data
that
reuses
the
same
segment
of
call
data
that
you
already
provided
with
the
order
and
cut
down
on
the
overhead
of
doing
this.
A
But
then
what
the
offerer
that's
getting
called
will
basically
have
to
do
is
rehash
the
order,
derive
that
digest
and
compare
it
to
the
one
that
was
supplied
by
1271.
Then
it
knows
that
the
order
that
you
gave
is
the
signature
is
in
fact
the
correct
order,
that's
being
filled
at
the
moment,
and
then
it
can
go
and
look.
Okay,
let's
check
out
this
offer
item
this
consideration
item
and
make
sure
that
they
match
whatever
the
the
latest
state
that
we
expect
is.
A
So
this
is
not
zones.
This
is,
if
you
have
a
contract
that
is
going
to
serve
as
an
offer,
and
so
it
could
have
its
own
validation
Logic
on
the
contract
as
part
of
this,
but
it
could
also
utilize
a
zone
right,
that's
very
much
a
something
that
it
could
piggyback
on
validation,
logic
in
his
own,
all
right.
So
that's
creating
orders.
A
Let's
talk
about
fulfilling
them.
The
standard
method
for
fulfilling
an
order
is
to
call
this
function.
Fulfill
order
and
or
fulfill
orders
is
the
actual
function,
and
you
basically
just
give
this
whole
payload.
Just
like
the
payload
that
you
signed,
you
provided
to
this
function
and
it
creates
an
implied
second
order,
a
mirror
image
of
the
first
one,
where
every
item
that's
being
offered
on
the
order.
You're
fulfilling
you
just
say
all
right,
I
will
take
that
and
take
all
of
those
items.
A
Port
doesn't
actually
have
a
notion
of
fees
at
all.
So
it's
everything
is
just
another
item.
But
if
you
have
one
of
these
simple
subsets,
you
got
a
single
offer
item.
You've
got
one
or
more
consideration
items,
and
you
take
that
sum.
Total
of
all
the
items
there's
one
nft.
That's
part
of
that
everything
else
is
a
single
item
type.
It's
a
they're,
all
Wes
or
they're
all
die
or
something
like
that.
Then
you
can
call
this
other
function
and
performs
a
more
optimized
fulfillment,
less
call
data.
A
You
just
need
to
supply
a
subset
like
give
all
the
additional
recipients
which
spells
out
usually
it's
used
for
fees
and
on
top
of
that
the
basic
fulfillment
methods
have
a
slight
deviation.
Where,
if
the
offer
is
the
item
is
a
erc20
token
or
native
token,
then
it
will
be
used
to
pay
for
all
the
non-nft
consideration
items.
So
you
don't
have
to
take
everything
you
can
minimize
the
number
of
transcripts
that
are
occurring.
A
That's
a
common
theme
with
you'll
see
as
we
get
into
these
subsequent
fulfillment
methods.
It's
all
about
cutting
down
on
the
top
efficiency
gain
is
from
reducing
the
number
of
transfers
right,
particularly
with
tokens
native
tokens
a
little
different,
but
with
other
tokens
it
gets
very
expensive
if
you're
doing
redundant
transfers.
A
Oftentimes
you'll
have
each
one
of
those
has
a
fee
attached.
What?
If
those
that
fee
recipient
is
the
same
recipient,
you
don't
want
to
do
five
transfers.
You
want
to
do
one,
so
we
use
this
fulfill
available
orders
method.
This
basically
goes
through
each
order
and
says:
has
this
been
fulfilled?
Has
it
been
canceled?
If
it's
still
valid,
then
we'll
go
for
it?
If
the
order
is
not
valid
anymore,
we'll
skip
it
and
you
supply
the
you
basically
point
to
okay.
A
A
Then
you
have
this
method
match
orders
when
you're
talking
about
fulfill
orders,
fulfill
available
orders
seaport's
not
going
to
be
able
to
figure
out
on
its
own
how
to
do
these
transfers.
The
way
that
it
works
is
you're
going
to
walk
through
every
single
fulfillment
and
it's
the
same
idea
as
fulfill
available
orders.
Here's
the
order!
Here's
an
item!
Here's
another
item!
Here's
another
item:
let's,
let's
aggregate
all
these
together,
then
we're
going
to
match
those
with
this
item.
A
A
This
is
what
you
really
want
to
reach
for
in
the
power
use
cases
where
you
have
your,
maybe
you're,
searching
like
you're
looking
for
Mev,
where
you
can
find
a
price
mismatch,
or
you
want
to
compose
multiple
different
orders
with
zones
and
get
them
all
to
all
fit
together
in
a
neat
little
puzzle.
Piece,
big
big
thing
to
be
aware
of
with
this-
is
that
if
there's
a
problem
after
you
supply
all
these
fulfillments,
it's
going
to
go
through
and
make
sure
that
every
single
consideration
item
on
every
single
order
has
been
fully
credited.
A
A
Okay,
let's
talk
about
some
zones
zones
is
the
it's
the
main
mechanic
by
which
you
would
extend
Seaport
any
order
can
choose
its
own
Zone
and
then
say
I'm
a
restricted
order,
except
the
type
is
restricted.
Now
the
Zone
gets
to
decide
whether
or
not
the
orders
good
or
bad,
and
in
addition,
you
can
always
extend
the
consideration
array.
You
can
always
add
items
as
the
fulfiller.
A
We
call
them
tips.
This
is
it's
cool
because
you
can
take
an
order
that
came
from
One
Marketplace.
You
can
fulfill
it
on
another
and
apply
a
tip.
What
you
can
also
do
is
you
can
use
logic
in
the
zones
to
ensure
that
the
tip
that
got
supplied
matches
whatever
it
is
that
that
you
expect
it
to
maybe
that's
a
dynamic
calculation
of
on-chain
royalties
right.
Something
like
that.
A
So
let's
talk
about
a
couple
potential
zones,
things
you
could
use
them
for
so
one
application
of
zones
is
for
dynamic,
nft
metadata
certain
items
in
Seaport,
they're,
called
criteria-based
items
and
in
place
of
giving
a
token
ID
an
identifier.
You
instead
give
a
Merkle
root
and
this
Merkle
root
is
comprised
of
all
the
token
IDs
that
are
valid
or
you
can
give
an
empty
one,
and
that
signifies
it's
a
wild
card.
A
A
Another
cool
potential
use
case
is
for
front
running
resistance,
say:
I
have
a
Zone
where
I
have
to
call
five
minutes
ahead
of
time
and
commit
similar
to
how
you
would
do
it
with
I.
Believe
ens
has
a
similar
thing.
You
register
ahead
of
time
and
say
I
want
to
fill
this.
Then
you
wait
some
period
of
time
and
then
you
reveal
you
include
as
part
of
the
the
parameters
called
extra
data
when
you're
fulfilling
that
gets
passed
along
to
the
zone.
A
A
Another
interesting
one
is
leveraging
Oracles.
Maybe
I
have
a
listing.
I,
don't
want
this
listing
to
be
fulfillable.
If
the
floor
falls
out,
so
I
could
read
from
an
oracle
that
is
periodically
updated
and
if
the
price
drifts
too
much
then
cancel
the
order,
don't
let
it
be
fulfilled
or
you
can
even
leverage
this,
along
with
that
trick,
with
Dynamic
orders
with
1271
to
create
a
strategy
that
will
buy
nfts
below
the
floor
price,
sell
nfts
above
the
floor
price.
That
kind
of
thing.
A
A
And
then
this
last
link
Seaport
order
validator.
This
is
a
contract
that
we
put
together
to
make
it
easier
for
checking
an
order
or
if
you
are
accepting
new
orders
coming
in
there's
a
lot
there's
a
lot
of
gotchas
things
that
can
go
wrong
and
it's
a
quick
way
to
say.
Oh,
this
order
looks
like
you're
not
actually
getting
anything
from
the
order
right,
you're
not
set
as
one
of
the
recipients
on
a
consideration
item.
A
You
sure
you
want
to
do
this,
there's
a
hundred
permutations
of
things
that
can
be
maybe
a
warning
or
a
not
right,
error
right,
so
it'll
check
on
chain
registry
for
Creator
information
like
make
sure
that
the
the
tokens
Implement
EIP
165
that
you're
not
trying
to
pretend
like
one
one
token,
that's
actually
a
as
nfts
and
erc20
token,
something
like
that
all
kinds
of
interesting
stuff
and
if
you're,
trying
to
just
piece
together
the
potential
things
that
can
go
wrong.
This
is
a
great
resource.
A
B
A
Yeah,
so
the
basic
approach,
as
I
mentioned
earlier
Seaport,
doesn't
have
any
notion
of
fees
or
royalties
it's
baked
in
it's
just.
You
could
very
easily
create
an
order
that
doesn't
include
any
fees
or
royalties
whatsoever,
so
it's
really
up
to
the
discretion
of
the
application
layer
whoever's
building
on
top
of
it.
A
One
approach
you
can
take
that
I
think
is
a
pretty
good.
One
is
to
just
read
from
the
Registries
at
the
time
the
order
is
created
this,
depending
on
your
perspective,
is
either
a
feature
or
a
bug.
One
thing
that
I
would
consider
a
bug
is
if,
when
I
go
to
create
a
listing,
the
royalty
is
five
percent
and
I'm.
A
Like
okay
I
sign
my
listing
now,
the
Creator
goes
and
changes
that
to
50
that's
a
problem
and
I
might
not
have
listed
it
if
I
knew
that
I
was
gonna
have
to
pay
that
right,
then
there's
also
the
question
of
well
what
if
they
just
want
to
tweak
the
recipient
of
the
royalty
or
something
like
that
for
those
cases
you
can
Leverage
tipping
right.
So
I
mentioned
earlier
that
you
can
always
add
additional
items
to
the
consideration
array.
You
can't
add
them
to
the
offer
right.
A
You
can't
decide
that
the
offerer
is
going
to
spend
more
than
they
originally
agreed
to.
That's
that's
a
very
important
and
variant
not
to
break,
but
you
can
always
say:
oh
yeah,
I'll
I'll
give
out
something
extra.
You
combine
that
with
call
it
a
a
royalty
Zone.
The
royalty
Zone
will
go.
It
will
read
from
in
real
time
from
the
registry
and
ensure
that
the
last
consideration
item
this
tip
matches
what
the
registry
has
on
file.
A
C
I
have
a
question
about
one
of
your
earlier
slides,
so
you
on
the
matching
orders
slide.
You
have
this
statement,
which
you
wrote
something
along
the
lines
of
like.
If
a
Searcher
identifies
an
opportunity
there,
it
is
so
search
your
identifies
an
opportunity
you
can
take
whatever
leftover
item
amounts
and
match
them
to
a
new
consideration
item
to
itself
so
I'm
a
little
confused,
because
my
understanding
of
the
architecture
is
that
in
every
single
type
of
order
or
function
call
you
make.
C
All
considerations
have
to
be
met
on
the
other
side,
so
I'm
a
little
confused.
How
like
like
in
the
in
the
case
of
like
the
classic
case
of
Arbitrage
right
like
there,
has
to
be
an
opportunity
on
the
table
for
the
arbitrager
to
take,
and
it's
not
clear
to
me
what
this
means
for
for
an
opportunity.
If
the
considerations
are
always
evened
out
or.
A
Yeah,
it's
a
great
question
and
this
is
actually
a
good,
a
good
opportunity
to
get
into
just
the
the
nitty-gritty
on
how
this
would
look.
Let's
just
consider
a
really
simple,
stripped
down
case
where
you
have
one
listing.
So
the
way
this
might
look
is
I
want
to
sell
my
nft
right.
So
I
have
one
offer
item.
Which
is
my
nft
and
one
consideration
item
we'll
call
it
five:
what
okay
with
the
recipient?
Being
me
the
offerer
right
now
someone
else
likes
my
nft.
A
They
don't
realize
that
I've
already
listed
it
for
five.
What
okay
they
put
out
an
offer,
a
bid
on
the
nft
to
buy
it
and
they
offer
six
web,
so
the
weight
would
look
for
them
is
I'm
offering
six
weft
one
offer
item
one
consideration
item
this
nft
recipient.
Is
me
so
now
person
number
three
Searcher
comes
along
and
realizes
that
there's
this
mismatch.
A
They
call
match
orders
they
Supply
both
of
these
orders
and
they
give
a
fulfillment
saying
Okay
order,
zero
item.
Zero
is
the
nft
order.
One
item
zero
on
the
consideration
side
is
also
the
nft
these
match.
That
turns
into
a
single
transfer.
From
the
offerer
A
to
offerer
B,
then
we
do
another
match.
Fulfillment
order.
Zero
item
I'm
sorry
order.
One
item
zero,
which
is
the
six
weft
order.
0
item
zero
on
the
consideration
side
is
the
the
five
width
those
now
match.
A
The
way
that
this
works
now
is
that
they
get
the
the
five
weft
gets,
credited
okay,
that's
been
accounted
for.
The
six
weth
gets
spent.
There's
one
wealth
left.
You
can
actually
leave.
Offer
item
amounts
on
the
table.
There's
not
there's
not
a
reason
that
you
have
to
spend
all
of
the
offer
items,
but
you
do
have
to
credit
all
of
the
consideration
items,
so
we
could
leave
it
at
that.
You
could
match
those
two
orders
and
the
original
or
the
the
order
be
the
person
that
made
the
bid
just
end
up
paying
five.
A
But
what
would
in
practice?
What
would
happen
is
that
this,
the
person
who
located
the
opportunity
might
say
I'm
going
to
create
a
third
order
and
this
third
order
I'm
offering
nothing.
It's
an
empty
array,
consideration
item
one
with
recipient
is
me
and
then
they
create
another
fulfillment
that
you
know
matches
the
the
same.
One
that
we've
just
spent
five
from
with
the
new
one
you
don't
even
have
to
create
a
new
order.
You
can
also
just
add
on
a
tip
to
order
b
or
whatever
and
use
that
to
match
to.
D
E
A
A
So,
if
an
order
supports
partial,
fills
the
way
that
this
works
is
that
you
can
supply
when
you
call
a
normal,
it's
like
fulfill
order,
fulfill
available
orders
match
orders,
those
don't
do
partial
fills,
but
there's
an
also
fulfill
Advanced
orders
match
Advanced
orders
fulfill
available,
Advanced
orders,
those
you
give
criteria
resolvers,
basically
Merkle
proofs
for
the
criteria-based
items
as
well
as
fill
fraction
a
numerator
and
a
denominator
and
the
the
heuristic
is
that
every
single?
Assuming
that
the
order
supports
it.
A
A
The
easiest
way
to
do
it
is
to
start
with
a
single
quantity
right.
I
have
some
ERC
1155
tokens
that
I
want
to
sell
for
one
eth.
Each
right
I
want
to
sell
10,
so
I'll
now
just
take
the
one.
Eighth
multiply
that
by
10.
take
all
the
fees
that
were
already
calculated
multiply,
those
by
10.,
so
it'll
be
a
nice
even
fraction.
That's
applied
the
math
behind
that
on
the
contract
is
also
pretty
cool.
A
The
uses
the
euclidean
algorithm
to
ensure
that
there's,
if
there's
an
overflow,
we
can
all
be
rounded
down
to
the
greatest
common
divisor.
But
that's
that's
different
topics.
Yes,
there's
partial
fills
and,
and
once
the
basically
once
the
fraction
The
Fill
fraction
is
applied
and
all
the
criteria
resolvers
are
applied
and
it's
all
the
exact
same
flow.
As
with
the
standard
stuff,
yeah.
F
A
Yeah
yeah,
so
2098
is
the
64
byte
signatures.
So
a
standard
ecdsa
in
ethereum
has
three
parameters
right:
v,
r
and
s
and
turns
out
that
there's
there's
a
parody
to
the
V
right.
It's
almost
always
27
or
28
right
and
there's.
Basically,
a
signature
malleability
concern
there,
where
you
have
two
exactly
identical
or
the
the
signatures
are
different,
but
they
resolve
to
the
same
record.
They
recover
to
the
same
signer.
A
Well,
the
trick
is
basically
to
say
what,
if
we
just
always
flip
the
parody
right,
so
you
can
take
any
65,
byte
signature
and
you
compress
you
flip
it
so
that
the
parity
is
always
I,
think
27,
and
then
you
also
can,
because
when
the
parody
is
that
27,
then
the
S
value
won't
use
the
most
significant
bit.
So
then
you
can
compress
V
and
S
into
a
single
word.
A
G
Hi
so
I
assume
I'm
trying
to
do
like
a
searching
strategy
right
so
to
help
users
with
a
gas
you
may
take
like
signed
orders
right
and
those
are
not
visible
on
chain.
So
for
a
Searcher
to
like
look
through
all
the
possibilities
of
orders
out
there,
that
I
could
possibly
fill
with
a
match
order.
Where
would
I
get
a
list
of
all
the
orders
that
are
not
on
chain
like?
Is
there
a
HTTP
API
that
I
could
call.
A
So
this
this
really
it
delves
into
less
of
how
does
Seaport
do
it
and
more
all
right?
What
about
the
marketplaces
they're
built
on
top
of
Seaport
right?
We
work
at
openc.
We
have
an
API.
If
you
have
access
to
the
API,
then
you
can
read
from
the
API
and
and
get
a
sense
of
yours.
There
are
also
other
marketplaces
they're
built
on
top
of
Seaport.
A
You
might
want
to
be
pulling
from
those,
but
it
does
get
more
complicated
to
find
all
of
that,
you
can
listen
on
chain
for
the
validate
events
right,
which
is
one
way
to
do
it.
You
can
listen
in
the
mempool
there's
another
way
right
so,
but
there
is
I
think
it's.
It's
definitely
an
area
of
active
investigation
to
figure
out
how
to
best
democratize
that
search.
Okay.
Thank
you.
A
Absolutely
so,
when
you
look
at
an
offer,
consideration
the
items
eth
or
native
tokens,
erc20
721
1155,
any
combo
of
those
Seaport
is
totally
fine.
With
the
exception
is
the
fulfilled
basic
order.
Method
does
have
more
opinionated
subset
of
the
possible
orders
that
it's
going
to
support,
but
yeah
Seaport
was
built
with
this
idea
of
barter
like
nft
for
nft
as
a
first
classes.
E
Yeah
I
guess
the
second
question
I
have
might
be
a
little
bit
yeah
of
a
comparison
question,
so
we
we're
right
now
integrated
with
like
Xerox
V3,
for
awesome
for
private
Marketplace,
so
I'm
just
curious
I
mean.
Maybe
you
can
speak
to
like
some
of
the
differences
between
C
port
and
Xerox
V3.
Does
any
yeah
yeah.
A
So,
first
off
Xerox
is
really
cool.
They
are
definite
innovators
in
the
space.
0X
is
more
geared
around
single
nft
like
buy
an
nft,
sell,
an
nft,
and
it's
it's
actually
a
very
good
protocol
for
that
Seaport
is
more
geared
around.
How
do
you?
How
do
you
grow
out
from
that?
There's
less
less
opinionated
on
this?
What
the
exact
structure
of
a
listing
looks
like
basically
for
the
exact
reasons
that
we're
just
discussing
is
a
top
one.
A
Another
thing
that
is
different
is
that
Seaport
is
totally
unowned
and
permissionless.
There's
no
special
notion
of
like
a
protocol
token
or
a
protocol
fee
that
could
be
turned
on.
It's
just
meant
to
serve
as
a
permissionless
piece
of
public
infrastructure
on
chain,
so
that
is
a
difference
and
but
yeah
big
fans
of
what
the
Xerox
team
has
been
able
to
do.
Thanks.
A
I
can't
speak
too
directly
for
openc
I'm
I'm
one
of
many,
but
what
I
can
say
is
that
for
at
least
a
couple
of
months
after
Seaport
first
went
live,
it
was
a
brand
new
protocol
used
a
lot
of
assembly,
and,
and
so
we
we
kept
guard
rails
on.
We
used
a
global
plausible
Zone
and
required
that
all
orders
that
were
sent
to
open
sea
had
this
Zone
set
on
them,
and
it
would
allow
for
us
to
basically
hit
the
panic
button
and
just
cancel
every
single
order.
A
If
there
was
a
problem
with
the
marketplace,
it's
now
been
long
enough
and
there
are
enough
interesting
use
cases
for
zones
that
efforts
are
underway
to
really
open
that
up.
Other
other
chains
off
of
mainnet
don't
currently
use
its
own.
So
stay
tuned.
Stay
tuned
on
that
and
I
will
also
say
that
if
anyone
is
authoring
zones
or
working
on
them
get
in
touch,
let
us
know
we'll.
A
A
So
if
you
have,
if
you
have
an
order,
that's
signed
and
the
signature
is
valid
right
like
you
can
recover
the
signature
and
it
works.
There
are
a
number
of
potential
things
that
you
could
look
into.
The
first
would
be
checking
the
order
validator
right,
that's
that's
going
to
scan
through
and
give
you
a
number
of
potential
problems
when
you
go
to
try
and
fulfill
it
and
that's
actually
it's
a
very
important
thing.
If
you
are
maintaining
listings
and
offers
you
have
to
ensure
that
you're
not
putting
listings
out
that
aren't
fulfillable
right.
A
So
that's
one
thing
to
try.
Another
Seaport
has
this
notion
of
a
counter,
so
every
single
offerer
has
a
counter.
That's
tracked,
independent
of
all
of
their
orders
and
at
any
point
you
can
just
call
increment
counter
and
that
serves
as
an
eject
button
where
all
the
orders
that
are
signed
with
that
counter
are
now
invalid.
A
Interestingly,
though,
you
don't
Supply
the
counter
as
an
explicit
argument,
it's
an
implied
argument.
So
if
you
have
two
identical
orders,
except
one
has
counter
zero.
One
has
counter
one
they'll
have
different
order
hashes,
but
the
call
is
the
same.
So
that's
one
potential
area
that
you
can
run
into
issues.
A
I
would
really
encourage
you
to
go
to
this
discussions
board
both
for
it's
a
great
Forum
to
lay
out
all
the
information
and
also
for
others
to
then
benefit
from
figuring
it
out,
and
so
I'd
encourage
you
to
to
do
that.
But
yeah
signatures
are
are
notoriously
finicky
to
work
with,
and
it
every
every
developer.
That's
that's
had
to
work
with
them
that
there's
always
a
sense
of
relief
when
you
finally
get
your
workflow
figured
out
and
and
the
signatures
are
working,
because
it
can
be
quite
opaque
why
things
are
going
wrong.
A
So
it's
actually
not
related
to
canceling,
when
I
call
cancel
on
an
order
that
cancels
a
specific
order
and
that's
actually
one
of
the
only
times
you
do
explicitly
provide
the
counter.
So
it's
saying
here's
a
particular
order
that
I
want
to
cancel
when
you
call
increment
counter,
you
don't
provide
any
arguments,
you
just
call
increment
counter
and
it
cancels
all
of
your
orders
that
were
signed
with
that
counter.
E
A
E
A
A
A
A
One
kind
of
interesting
way
of
doing
that
is
just
to
say
all
right,
single
offer
item
my
nft
consideration
item.
One
is
eth
to
me
consideration
item
two
is
my
nft
to
you
right,
so
I've,
basically
just
set
it
all
up,
but
now,
if
I
wanted
to
go
and
call
these
implied
mirror
order-
and
you
know
just
fulfill
orders
on
that-
it's
not
going
to
work
because
the
the
offer
item
from
me
needs
to
actually
match
to
the
same
order
right.
A
The
consideration
item
on
that
same
order,
so
you
got
to
use,
match
orders
for
that,
and
you
would
then
match
it
with
an
order
from
you
that
just
says
I'm
just
offering
the
eth
and
there's
no
consideration
item
right,
so
I'm
basic!
If,
if
I
were
to
just
take
that
order
and
sign
it,
then
it's
effectively
a
donation
right,
but
if
I
fulfill
it
alongside
this
other
order,
now
the
two
of
them
together
make
a
complete
picture.
So
that's
for
just
a
single
private
sale,
but
for
say,
I
only
want
to
sell
my
nft.
A
If
you're
on
this
allow
list,
that's
easy
enough.
You
have
a
Zone
where
you
just
Supply.
Okay,
here
is
a
Merkel
proof
that
says
that
the
fulfiller
the
caller
is
in
the
root
right.
They're,
one
of
a
set
of
people
or
I
could
check
and
see
like
the
caller,
has
a
balance
of
this
particular
token.
If
it
don't
want
it
to
be
a
token
gated
thing,
where
only
someone
that
owns
this
token
can
buy
it
from
me
or
something
like
that.
Well,
that's
all!
Actually
it's
pretty
straightforward
to
do
with
his
own,
hey.
D
So
with
like
developing
new
zones
and
building
just
generally
on
top
of
Seaport
like
a
new
Marketplace,
do
you
see
it
as
like,
like
what's
the?
What
are
the
steps
for
for
doing?
That?
Is
that
like
create
a
UI
that
signs
messages
and
then
create,
like
your
own
database
and
API
to
serve
those
messages?
Do
you
see
that
happening
as
like
the
pattern
as
this
scales
out
or
like
develop
the
zone
and
then
like
work
with
openc
to
have
that
zone
integrated
or
maybe
like
a
mix
of
both
well.
A
We
knew
that
the
place
to
start
was
with
the
smart
contract
right,
the
marketplace:
that's
it's
the
hardest
and
riskiest
thing
and
most
expensive
to
get
audited
and
vetted,
and
all
of
that
so
started
with
that.
The
the
contract,
and
now
that
that's
in
place
really
where
we
go
from
here
is,
is
anyone's
guess,
but
I
think
that
if
it
really
depends
on
the
application,
if
you
have
a
particular
flavor
of
listing
that
you
want
to
see
supported
in
other
marketplaces,
then
I
think
the
most
expedient
route
to
do.
A
That
would
be
to
go
ahead
and
put
it
together
and
then
shop
it
around
and
sort
of
like
I
mentioned
earlier,
you
know
I!
Would
we
would
love
to
to
see
what
people
are
working
on
zones
they're,
creating
and
that
would
really
help
expedite
the
process
and
help
standardize
around
certain
zones
that
do
specific
things
really
well
they're,
creating
a
brand
new
Marketplace
from
from
the
ground
up
I
think
that's
it.
There
still
is
very
much
a
traditional
web
2
component
to
it.
That
would
need
to
be.
A
C
A
So
so
there's
no
Zone
required
on
Private
Sales.
That's
basically
just
taking
the
standard
order
and
normally
you'll
see
an
order
with
it's
like
the
basic
order.
You'll
have
a
single
offer
item.
That's
either
the
the
tokens
that
you
want
to
spend
or
the
nft
that
you
want
to
sell
and
then
you'll
have
one
consideration
item
the
first
one
by
convention
like
if
you
use
the
order,
validation,
helper
thing.
A
The
first
consideration
item
is
almost
always
going
to
be
something
coming
back
to
you,
the
offerer
right
and
then
it'll
be
followed
up
by
usually
fees
like
here's
a
fee
to
the
marketplace.
Here's
a
fee
to
the
Creator,
that's
the
standard
order
that
you
would
see,
but
in
Private
Sales
one
way
you
can
do
a
private
sale.
F
H
Like
I
think
when
I
was
reading,
the
like
Open
Seas,
like
wyvern
contracts
like
there,
was
support
for
just
Dutch
auctions
and
pixel
or
fixed
price
sales,
and
they
had
like
a
comment
in
it
saying
like
they
wanted
to.
Maybe
do
something
more
advanced
or
like
English
auctions,
or
something
like
that.
Right
and
I.
Remember
watching
one
of
your
like
I
guess
it
was
like
an
East
Denver
talk
or
something
like
that,
and
you
said
that
like
something
like
an
English
auction
or
that
could
be
possible
using
the
zones.
A
So
when
you
do
that,
it
will
look
at
the
start
time
and
the
end
time
on
that
particular
order,
and
then
it
does
it
a
linear,
interpolation
and
we'll
just
pick
out.
Okay,
here's
the
current
amount
based
on
where
we
are
along
the
the
timeline
for
the
order,
so
oftentimes
like
when
you
talk
about
a
Dutch
auction,
what
that
or
a
reverse
Dutch
option.
What
that
really
is
getting
at
is.
This
is
a
it's
a
sum
listing
where
the
price
is
going
down
over
time
right
or
the
price
is
going
up
over
time.
A
A
What
it
really
comes
down
to
is,
like
I,
have
a
reserve
price
and
I
want
that
reserve
price
to
be
met
and
I
want
that
reserve
price
to
be
secret
too
right.
So
like
one
way
to
handle
an
auction,
assuming
you
have
an
Auctioneer.
That
is
a
someone
you
trust.
Is
you
set
the
auction,
the
runner
of
the
auction
as
the
Zone
on
your
order
zones
generally.
The
way
that
we
would
think
of
them
is
that
when
you
have
a
restricted
order
that
zone
you're
gonna
call
it
and
say:
is
this
a
valid
order?
A
If
it
is
then
it'll
give
back
a
magic
value
saying
this
is
good
go
ahead,
but
another
way
you
can
do
it
is
that
that
zone
can
actually
call
Seaport
if
they
call
Seaport,
that's
also
them
if
they're
the
ones
that
are
fulfilling
the
order.
That's
also
them
giving
explicit
approval
per
se
right
their
message
sender,
so
you
can
basically
sign
a
listing
that
you
here's
my
my
reserve
price.
That's
the
consideration
item
to
me.
A
I'm
going
to
give
that
to
this
this
Auctioneer,
whatever
the
marketplace
they're
going
to
keep
the
order
Secret,
and
then
they
have
to
be
the
one
to
fulfill
it
right.
It's
a
restricted
order
and
they'll
apply
a
tip
on
that,
based
on
the
difference
between
the
reserve
price
and
the
actual
price.
There
are
also
constructions
where
you
can
do
stuff
like
the
commit
reveal
pattern
for
hiding
the
reserve
price.
You
generally
have
to
bond
up
front
I
mean
it
gets.
It
gets
complicated
depending
on
whether
you're
optimizing
for
the
privacy
of
the
the
person.