Googlebot: SEO Mythbusting – What Google Wants

Google’s main crawler is called Googlebot .

Googlebot retrieves the content of webpages (the words, code and resources that make up the webpage).

It then sends the information to Google.

Google uses this information in its Google search engine to determine what sites to display and to whom.

  • There are more than 3.5 billion Google searches every day
  • 76% of all global searches take place on Google
  • Google Search Index contains more than 100,000,000 GB
  • More than 60% of Google searches come from mobile devices
  • 16-20% of all annual Google search results are new
Google has put together a channel called SEO Mythbusting. This helps webmasters find out What Google Wants.

Martin Splitt (WebMaster Trends Analyst, Google) and his guest Suz Hinton (Cloud Developer Advocate, Microsoft) discuss the many intricacies of Googlebot such as:

What is – and what is not – Googlebot (crawling, indexing, ranking) (1:02)
Does Googlebot behave like a web browser? (3:33)
How often does Googlebot crawl, how much does it crawl, and how much can a server bear? (
Crawlers & JavaScript-based websites (
How do you tell that it’s Googlebot visiting your site? (
The difference between mobile-first indexing and mobile friendliness (
Quality indicators for ranking (

Below this is subtitles for the video





SUZ HINTON: A lot of
confusion revolves around SEO

because no one understands how
the Googlebot actually works.



welcome to another episode

of “SEO Mythbusting.”

With me today is Suz
Hinton from Microsoft.

Suz, what do you do at work,
and what is your experience

with front end SEO?

so right now, I’m

doing less front end these days.

I focus more on IoT.

time you were a front end


SUZ HINTON: Yeah, I was a front
end developer for, I think,

12 or 13 years.

And so I got to work on lots of
different contexts of front end

development, different web
sites, things like that.


I wanted to just

address a bunch of stuff
about Googlebot specifically,

and nerd out about
Googlebot, because that

was the side of things that
I was the most confused about

at the time.

is basically a program

that we run that
does three things.

The first thing is it
crawls, then it indexes,

and then last, but
not least, there’s

another thing that is not
really Googlebot anymore.

That is the ranking bit.

So we have to basically grab
the content from the internet,

and then we have to figure out
what is this content about?

What is the stuff that
we can put out to users

looking for these things?

And then last, but
not least, is which

of the many things that
we picked for the index

is the best thing for
this particular query

in this particular time?

SUZ HINTON: Got it, yeah.

ranking bit, the last bit,

where we move things around–
that is informed by Googlebot,

but it’s not part of Googlebot.

because there’s

this bit in the
middle, the indexing?

The Googlebot is
responsible for the indexing

and making sure that content is
useful for the ranking engine


Absolutely, absolutely.

You can imagine, someone
has to– in the library,

someone has to figure out
what the books are about

and get the index of the bits
in a catalog, the catalog

being our index, really.

And then someone else
is using that index

to make informed
decisions and going, here,

this book is what
you’re looking for.

really glad you used

that analogy because I worked
in a library for four years.

MARTIN SPLITT: So you know much
better than I how that works.

was that person.

People would be like, I
want Italian cookbooks,

and I’m like, well,
it’s 641.5495.

And you would just
give it to them.

come to you, as a librarian,

and ask a very
specific question,

like so what is the best book on
making apple pies really quick,

would you be able to figure
out, from the index–

you probably have
lots of cookbooks.

SUZ HINTON: We did, yeah.

We had a lot.

But given that I also put lots
of books back on the shelf,

I knew which ones were popular.

I’ve no idea if we can link
this back to Googlebot.


Yeah, it’s pretty much– so you
have the index that probably

doesn’t really change that much,
unless you add new books to it.

SUZ HINTON: New editions.

MARTIN SPLITT: Exactly, yeah.

So you have this index, which
Googlebot provides you with.

But then we have the second–

the librarian second
part that basically is,

based on how the interactions
with the index work,

figure out which
books to recommend

to someone asking for it.

So that’s pretty much
the exact same thing.

Someone figures out what
goes into the catalog,

and then someone uses it.

SUZ HINTON: I love this.

This makes total sense to me.

that’s still not necessarily

all the answers you need.

SUZ HINTON: Yeah, I just want to
know, what does it actually do?

How often does it crawl sites?

What does it do
when it gets there?

What does it– how is it
generally behaving like?

Does it behave
like a web browser?

a really good question.

Generally speaking, it behaves
a little bit like a browser–

at least, part of it does.

So the very first
step, the crawling bit,

is pretty much a browser
coming to your page,

either because we
found a link somewhere,

or you submitted a
site map, or there’s

something else that basically
fit that into our systems.

You can use Search Console
to give us a hint and ask

for re-indexing, and that
triggers a crawl before–

done that before.

MARTIN SPLITT: Oh, very good.

SUZ HINTON: We asked
for it to be done.

that is perfectly fine,

but the problem then,
obviously, is how often do you

crawl things, and how
much do you have to crawl,

and how much can
the server bear.

If you’re on the
backend side, you

know that you have
a bunch of load,

and that might not be
always the same thing.

If it’s like a Black
Friday, then the load

is probably higher
than on any other day.

So what Googlebot does is
it tries to figure out,

from what we have in
the index already,

is that something
that looks like we

need to check it more often?

Does that probably change?

Is it like a newspaper
or something?

SUZ HINTON: Got it, yeah.

is that something

like a retail site that
does have offerings that

change every couple of weeks?

Or even do not change at
all because this is actually

the site of a museum
that changes very rarely?

For the exhibitions maybe,
but a few bits and pieces

don’t change that much.

So we try to like segregate
our index data into something

that we call daily or
fresh, and that gets

called relatively frequently.

And then it becomes less and
less frequent as we discover,

and if it’s something that is
super spammy or super broken,

we might not crawl it as often.

Or if you specifically
tell us, do not index this,

do not put this
in the index, this

is something that I
don’t want to show up

in the search results,
and we don’t come back

every day and check.

So you might want to
use the re-index feature

if that changes.

You might have a page that you
go, no, this shouldn’t be here,

and then once it
has to be there,

you want to make sure that we
are coming back and indexing


So that’s the browser bit.

That’s the crawler part, but
then a whole slew of stuff

happens in between
that happening,

us fetching the content
from your server,

and the index having
the data that is then

being served and ranked.

So the first thing is
we have to make sure

that we discover if you have any
other resources on your page.

The crawling cycle
is very important.

So what we do is, the moment
we have some HTML from you,

we check if we have
any links in there,

or images for that
matter, or video–

something that we
want to crawl as well,

and that feeds right back
into the crawling mechanism.

Now, if you have a
gigantic retail site,

let’s say, just
hypothetically speaking,

we can’t just crawl
all the pages at once,

both for our
resource constraints,

but also we don’t want to
overwhelm your service.

So we basically
try to figure out

how much strain we can
put on your service

and how much resources
we’ve got available as well,

and that’s called the
crawl budget, oftentimes.

But it’s pretty tricky to
determine, so one thing

that we do is we
crawl a little bit,

and then basically ramp it up.

And when we start
seeing errors, we

ramp it down a little bit more.

So oops, sorry, for that,
we are not– oh, ugh.

So whenever your service
serves us 500 errors,

there are certain tools
in Search Console that

allow you to say, hey, can you
maybe chill out a little bit.

But generally, we don’t try
to get all of it at once

and then ramp down.

We are trying to carefully ramp
up, ramp down again, ramp up

again, ramp down again, so
it fluctuates a little bit.

SUZ HINTON: There’s a
lot more detail in there

than I was even expecting.

I didn’t even know that–

I guess I never considered
that a Googlebot crawling

event could put strain
on somebody’s website.

That sounds like it’s a
lot more common than I even

thought it would be.

happen, especially

if we discover, say,
a page that has lots

of links to subpages pages.

Then all of these go
into the crawling queue,

and then you might–

let’s say you have 30
different categories of stuff,

and each of these have a few
thousand products and then

a few thousand
pages of products.

So we might go, oh, cool, crawl,
crawl, crawl, crawl, crawl,

crawl, crawl, and then we
might crawl a few hundred

thousand pages.

And if we don’t spread
that out a little bit–

so it’s a weird balance.

On one hand, if you
add a new product,

you want that to be surfaced
and searched as quickly

as possible.

On the other hand,
you don’t want

us to take all the bandwidth
that your server offers.

I mean, cloud computing makes
that a little less scary,

I guess, but I
remember the days–

I’m not sure if you
remember the days where

you had to call someone,
and they ask you

to send a form or fax a form.

And then two weeks later, you
get the confirmation letter

that your server
has been started.

remember the days

when we would have to call,
and then we would basically

pay $200 to have a
human go down the aisles

and push the physical reset
button on the server, so yeah.

MARTIN SPLITT: Those times
were a lot trickier, yeah.

And then imagine you basically
renting five servers somewhere

in a data center, and
that taking a week,

and then we come and scoop
up all your bandwidth.

And you’re like, great,
we’re offline today

because Google
has its crawl day.

That’s not what we want to have.

these days, it’s

more like a happy news kind
of moment, when you get hit.


feel like you’re

much more considerate than–

MARTIN SPLITT: Yeah, we try
to not overwhelm anyone,

and we respect the robots.txt.

So that works within
the crawl step as well.

And once we have the
content, we can’t

put strain on your

anymore, so that’s fantastic.

But modern web apps being
mostly JavaScript driven,

we then put that in
a queue, and then

once we have the
resources to render it,

we actually use another
headless browser kind of thing.

We call that the Web
Rendering Service.

Then there’s other
crawlers as well

that might not have the capacity
or the need to run JavaScript.

This is like social
media bots, for instance.

They come and look for metadata.

If that meta tag is
coming in with JavaScript,

you usually have a bad time,
and they’re just like, sorry.

SUZ HINTON: Yeah, so that’s
always been a big mess,

and I remember when single
page applications, or SPAs,

really came into vogue.

A lot of people were
really concerned.

There’s a lot of FUD around.

Well, if crawlers in general
don’t execute JavaScript,

then they’re going
to see a blank page,

and how do you get around that?

So contextually,
within Googlebot,

it sounds like Googlebot
executes JavaScript–


SUZ HINTON: Even if it does
do it at a later point.

MARTIN SPLITT: Yes, correct.

SUZ HINTON: So that’s good?

MARTIN SPLITT: That’s good.

is there anything

that people need to be
aware of beyond just,

oh, well, it’ll just
run it, and then

it’ll see exactly the same
thing as a human with a phone

or a desktop would see?

a bunch of things

that you need to be aware of.

So the most important thing
is, again, as you said,

it’s deferred.

It happens at a later point.

So if you want us to crawl your
stuff as quickly as possible,

that also means we have to
wait to find these links

that JavaScript injects.

Basically, we crawl, we have
to wait until JavaScript

is executed, then we
get the rendered HTML,

and then we find the links.

So the nice little
short loop that

finds these links relatively
quickly right after crawling

will not work.

So we will only see the
links after we render it,

and this rendering can take
a while because the web is

surprisingly big.

just a little bit.

MARTIN SPLITT: There’s 130
trillion docs in 2016, so–

there’s way more now.

There’s way more now.

There’s way more than that.

robots.txt is very

effective at being able to tell
bots how to do a certain thing.

But in this scenario,
how do you tell

that it’s Googlebot visiting
your site as opposed

to other things?

as we are basically

using a browser in two
steps– one is the crawling,

and one is the
actual rendering–

both of these moments, we do
give you the user agent header.

But basically,
there’s the string–

literally the string
Googlebot in it.

so straightforward.

and you can actually

use that to help with your
SPA performance as well.

So as you can detect
on the server side,

oh, this is Googlebot
user agent requesting,

you might consider sending
us a prerendered static HTML

version, and you can do the
same thing for the others.

All the other search engines
and social media bots

have a specific string
saying that they are a robot.

So you can then basically
go, oh, in that case,

I’m not giving you the real
deal, the single page app.

I’m giving you this HTML
that we prerendered for you.

It’s called dynamic rendering.

We have docs on that as well.

SUZ HINTON: The one thing
that still doesn’t quite

make sense to me is
does the Googlebot

have different contexts?

Does it sometimes
pretend that it’s–

I think of it as this
little mythical creature

that’s pretending to
do certain things.

So does it pretend to be on
a mobile, and then desktop?

Are the different, I
guess, user agents,

even though it still
says Googlebot?

And can you differentiate
between them?

MARTIN SPLITT: You’re asking
great questions, because yes,

we have different user agents.

So I’m not sure if you heard
about mobile first indexing

being rolled out and happening.

SUZ HINTON: I’ve heard
that it’s going to affect

how you’re ranked potentially.

MARTIN SPLITT: That as well.

SUZ HINTON: I don’t know if
that’s a rumor or not, yeah.

two different things

that get conflated so often.

So mobile first indexing
is about us discovering

your content using a mobile user
agent and a mobile viewport.

So we are using
mobile user agents,

and the user agent
strings says so.

It says something about
Android in the name,

and then you’re like, aha, so
this is the mobile Googlebot.

We have documentation on that.

There’s literally a
Help Center article

that lists all these things.

So we try to index
mobile content

to make sure that
we have something

nice to server for
people who are on mobile,

but we’re not pretending
random user agents or anything.

We stick to the
user agent strings

that we have documented
as well, and that’s

mobile first
indexing, where we try

to get your mobile content
into the index rather

than the desktop content.

Then there’s mobile readiness,
or mobile friendliness.

If your page is
mobile friendly, it

makes sure that everything
is within viewport,

and you have large enough
tap targets and all

these lovely things, and that
just is a quality indicator.

We call these signals.

We have over 200 of them.

SUZ HINTON: That’s a lot.


So Googlebot collects
all these signals

and then stuff them, as
metadata, into the index.

And then when we rank, we’re
like, so this user’s on mobile,

so maybe this thing that has a
really good mobile friendliness

signal attached to it might
be a better one than the thing

where they have to pinch
zoom all the way out

to be able to read anything,
and then can’t actually

deal with the different
links because they’re

too close to each other.

So that’s one of the many–

it’s not the signal.

It’s one of the many signals.

It’s one of the over 200
signals to deal with.

SUZ HINTON: I had no
idea there were 200.

That’s making me–

I know that you’re not
allowed to share what they all

are because there has to be
a certain mystique around it,

because of, I guess, a lot
of SEO abuse in the past.

yeah, unfortunately, that

is a game that is
still being played,

and people are doing weird
stuff to try to game us.

And the interesting thing with
this is, with the 200 signals,

it’s really hard
to say which one

gets you moving in the ranks.

SUZ HINTON: The weights
of each signal because–

MARTIN SPLITT: And they keep
moving, and they keep changing.

I love when people are like, no,
let’s do this, and then, look,

my rank changes.

Yeah, for this
one query, but you

lost on all the other queries
because you did really

weird and funky stuff for that.

So just build good
content for the users,

and then you’ll be fine.

SUZ HINTON: I feel like that–

it feels like less
effort as well,

than constantly trying to–

it’s not an easy answer.

You pay me to make you more
successful on search engines,

and I come to you and say,
so who are your users,

and what do they need,
and how could you

express that so that they
know that it’s what they need?

That’s a hard one because
that means I basically

bring the ball back
to you, and now, you

have to think about stuff and
figure it out, strategically.

Whereas if I’m like,
I’m just going to get

you links or do some
funky tricks here,

and then you’ll be
ranking number one.

That’s an easier answer.

It’s the wrong answer, but
it’s the easier answer.

So people are like, links are
the most important metric ever,

and I’m like, no.

We have over 200,
and it’s important,

but it’s not that important.

And chill out, everybody.

But this still happens.

glad it’s better now.

I feel, actually, more at peace
in general with SEO, as well,

after speaking to you today.

MARTIN SPLITT: Ah, so good.

Suz, thank you so
much for being with me

here, and has been
a great pleasure.

thanks for answering

all of my weird and wonderful
questions about the Googlebot.

Perfect questions.

Perfect opportunity.

Did we bust some myths?

SUZ HINTON: I feel like we did.


I think that’s
worth a high five.

SUZ HINTON: Awesome.



Join us again for the next
episode of “SEO Mythbusting,”

where Jamie Alberico
and I will discuss

if JavaScript and SEO can be
friends and how to get there.


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