Mempool Space

Mempool is a self-hosted Bitcoin blockchain and mempool visualizer/explorer. Look up your onchain transactions and estimate transaction fees without any privacy leaks.

Mempool Space preview

Preparations

Transaction indexing

For the Mempool Space to work, you need your full node to index all transactions.

If you followed this guide, the transaction index parameter is already enabled (txindex=1), and you can skip to the next section.
If this is not the case, you need to set the txindex=1 parameter in your Bitcoin client configuration file (bitcoin.conf): Bitcoin node configuration.
After adding the parameter, restart Bitcoin client, which will now index the whole blockchain

$SU rc-service bitcoind restart

Please note that reindexing can take more than a day. You can follow the progress using

tail -f /var/log/bitcoind/debug.log

Install dependencies

Install Node.js using the apk package manager.

These are build dependencies (safe to remove after installation, if you want)

$SU apk add --virtual .build-deps cargo git gnupg npm rsync

These are runtime dependencies

$SU apk add mariadb mariadb-client nodejs-current

Create the `mempool` user/group

$SU addgroup -S mempool

$SU adduser \
    -S \
    -D \
    -H \
    -h /dev/null \
    -s /sbin/nologin \
    -G mempool \
    -g mempool \
    mempool

Add `mempool` user to the `bitcoin` group

$SU adduser mempool bitcoin

Add `satoshi` user to the `mempool` group

$SU adduser satoshi mempool

Reverse proxy

In the Security section, we set up a reverse proxy. Now we can add the Mempool Space configuration.

Enable the reverse proxy to route external encrypted HTTPS traffic internally to the Mempool Space

$SU $EDITOR /etc/caddy/sites/mempool-space.caddy

/etc/caddy/sites/mempool-space.caddy

:4081 {
    import tls
    root /var/www/mempool/browser
 
    handle /api/v1/* {
        reverse_proxy 127.0.0.1:8999
    }
 
    handle /api/* {
        uri replace /api/ /api/v1/
        reverse_proxy 127.0.0.1:8999
    }
 
    handle {
        map {header.accept-language} {header_lang} {
            default "en-US"
            ~^ar "ar"
            ~^cs "cs"
            ~^da "da"
            ~^de "de"
            ~^en "en-US"
            ~^es "es"
            ~^fa "fa"
            ~^fi "fi"
            ~^fr "fr"
            ~^he "he"
            ~^hi "hi"
            ~^hr "hr"
            ~^hu "hu"
            ~^it "it"
            ~^ja "ja"
            ~^ka "ka"
            ~^ko "ko"
            ~^lt "lt"
            ~^mk "mk"
            ~^nb "nb"
            ~^ne "ne"
            ~^nl "nl"
            ~^pl "pl"
            ~^pt "pt"
            ~^ro "ro"
            ~^ru "ru"
            ~^sl "sl"
            ~^sv "sv"
            ~^th "th"
            ~^tr "tr"
            ~^uk "uk"
            ~^vi "vi"
            ~^zh "zh"
        }
 
        map {cookie.lang} {lang} {
            default {header_lang}
            ar "ar"
            cs "cs"
            da "da"
            de "de"
            en "en-US"
            es "es"
            fa "fa"
            fi "fi"
            fr "fr"
            he "he"
            hi "hi"
            hr "hr"
            hu "hu"
            it "it"
            ja "ja"
            ka "ka"
            ko "ko"
            lt "lt"
            mk "mk"
            nb "nb"
            ne "ne"
            nl "nl"
            pl "pl"
            pt "pt"
            ro "ro"
            ru "ru"
            sl "sl"
            sv "sv"
            th "th"
            tr "tr"
            uk "uk"
            vi "vi"
            zh "zh"
        }
 
        header {
            Cache-Control "public, no-transform, max-age=1800"
            Vary "Accept-Language, Cookie"
        }
 
        @lang-override path_regexp ^/([a-z]{2})/
        handle @lang-override {
            try_files {path} /{re.lang-override.1}/index.html /en-US{path} /en-US/index.html
        }
 
        handle {
            try_files {path} /{lang}{path} /en-US{path} /{lang}/index.html /en-US/index.html
        }
 
        file_server
    }
}

Reload Caddy

$SU rc-service caddy reload

$SU $EDITOR /etc/nginx/sites-available/mempool-reverse-proxy.conf

/etc/nginx/sites-available/mempool-reverse-proxy.conf

proxy_read_timeout 300;
proxy_connect_timeout 300;
proxy_send_timeout 300;
 
map $http_accept_language $header_lang {
    default en-US;
    ~*^en-US en-US;
    ~*^en en-US;
    ~*^ar ar;
    ~*^ca ca;
    ~*^cs cs;
    ~*^de de;
    ~*^es es;
    ~*^fa fa;
    ~*^fr fr;
    ~*^ko ko;
    ~*^it it;
    ~*^he he;
    ~*^ka ka;
    ~*^hu hu;
    ~*^mk mk;
    ~*^nl nl;
    ~*^ja ja;
    ~*^nb nb;
    ~*^pl pl;
    ~*^pt pt;
    ~*^ro ro;
    ~*^ru ru;
    ~*^sl sl;
    ~*^fi fi;
    ~*^sv sv;
    ~*^th th;
    ~*^tr tr;
    ~*^uk uk;
    ~*^vi vi;
    ~*^zh zh;
    ~*^hi hi;
}
 
map $cookie_lang $lang {
    default $header_lang;
    ~*^en-US en-US;
    ~*^en en-US;
    ~*^ar ar;
    ~*^ca ca;
    ~*^cs cs;
    ~*^de de;
    ~*^es es;
    ~*^fa fa;
    ~*^fr fr;
    ~*^ko ko;
    ~*^it it;
    ~*^he he;
    ~*^ka ka;
    ~*^hu hu;
    ~*^mk mk;
    ~*^nl nl;
    ~*^ja ja;
    ~*^nb nb;
    ~*^pl pl;
    ~*^pt pt;
    ~*^ro ro;
    ~*^ru ru;
    ~*^sl sl;
    ~*^fi fi;
    ~*^sv sv;
    ~*^th th;
    ~*^tr tr;
    ~*^uk uk;
    ~*^vi vi;
    ~*^zh zh;
    ~*^hi hi;
}
 
server {
    listen 4081 ssl;
 
    sendfile on;
    tcp_nopush on;
    tcp_nodelay on;
 
    server_tokens off;
    server_name_in_redirect off;
 
    default_type application/octet-stream;
 
    reset_timedout_connection on;
    client_body_timeout 10s;
    client_header_timeout 10s;
    keepalive_timeout 69s;
    send_timeout 69s;
 
    keepalive_requests 1337;
 
    gzip on;
    gzip_vary on;
    gzip_comp_level 6;
    gzip_min_length 1000;
    gzip_proxied expired no-cache no-store private auth;
    gzip_types application/javascript application/json application/ld+json application/manifest+json application/x-font-ttf application/x-web-app-manifest+json application/xhtml+xml application/xml font/opentype image/bmp image/svg+xml image/x-icon text/cache-manifest text/css text/plain text/vcard;
 
    client_max_body_size 10m;
 
    proxy_cache off;
    types_hash_max_size 2048;
 
    root /var/www/mempool/browser;
    index index.html;
 
    add_header Cache-Control "public, no-transform";
    add_header Vary Accept-Language;
    add_header Vary Cookie;
 
    location / {
        try_files /$lang/$uri /$lang/$uri/ $uri $uri/ /en-US/$uri @index-redirect;
        expires 10m;
    }
 
    location /resources {
        try_files $uri @index-redirect;
        expires 1h;
    }
 
    location /resources/config.* {
        try_files $uri =404;
        expires 5m;
    }
 
    location /resources/customize.* {
        try_files $uri =404;
        expires 5m;
    }
 
    location @index-redirect {
        rewrite (.*) /$lang/index.html;
    }
 
    location ~ ^/(ar|bg|bs|cs|da|de|et|el|es|eo|eu|fa|fr|gl|ko|hr|id|it|he|ka|lv|lt|hu|mk|ms|nl|ja|nb|nn|pl|pt|pt-BR|ro|ru|sk|sl|sr|sh|fi|sv|th|tr|uk|vi|zh|hi)/ {
        try_files $uri $uri/ /$1/index.html =404;
    }
 
    location = /api {
        try_files $uri $uri/ /en-US/index.html =404;
    }
 
    location = /api/ {
        try_files $uri $uri/ /en-US/index.html =404;
    }
 
    location /api/v1/ws {
        proxy_pass http://127.0.0.1:8999/;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "Upgrade";
    }
 
    location /api/v1 {
        proxy_pass http://127.0.0.1:8999/api/v1;
    }
 
    location /api/ {
        proxy_pass http://127.0.0.1:8999/api/v1/;
    }
 
    location /ws {
        proxy_pass http://127.0.0.1:8999/;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "Upgrade";
    }
}

$SU ln \
    -s \
    ../sites-available/mempool-reverse-proxy.conf \
    /etc/nginx/sites-enabled/mempool-reverse-proxy.conf

Test and reload NGINX configuration

$SU nginx -t
$SU rc-service nginx restart

Firewall

Configure the firewall to allow incoming HTTPS requests

$SU $EDITOR /etc/awall/optional/mempool.json

/etc/awall/optional/mempool.json

{
  "description": "Allow Mempool Space SSL",
 
  "filter": [
    {
      "in": "internet",
      "out": "_fw",
      "service": { "proto": "tcp", "port": 4081 },
      "action": "accept",
      "conn-limit": { "count": 10, "interval": 60 }
    }
  ]
}

Enable it

$SU awall enable mempool
$SU awall activate

Installation

Download source code

We get the latest release of the Mempool Space source code and install it.

Download the source code for the latest Mempool Space release. You can check the release page to see if a newer release is available. Other releases might not have been properly tested with the rest of the Microbolt configuration, though.

cd /tmp

VERSION=3.0.0

git clone --branch v$VERSION https://github.com/mempool/mempool.git && cd mempool

Signature check

To avoid using bad source code, verify that the release has been properly signed at least by one of the main developer wiz.

wget -qO- https://github.com/wiz.gpg | gpg --import

git verify-tag v$VERSION

MariaDB

MariaDB is an open source relational database.

First need to create initial databases and start the service

$SU rc-service mariadb setup
$SU rc-service mariadb start

These commands allow you to create a mempool database and grant privileges to mempool user directly from the command line

$SU mysql -e "create database mempool;"
$SU mysql -e "grant all privileges on mempool.* to 'mempool'@'localhost' identified via unix_socket;"

Backend

Install the backend dependencies and build the project

cd /tmp/mempool/backend

npm ci --omit=dev --omit=optional

Installation can take some time. There might be a lot of confusing output, but if you see something similar to the following, the installation was successful:

output

3 high severity vulnerabilities

To address all issues, run:
  npm audit fix

Run `npm audit` for details.

⚠️

At 2024-08-31 there is at least 3 high severity vulnerabilities not addressable without breaking changes

npm audit fix

Make it a global permanent installation

npm run package

mkdir ./package/bin

printf "%s\n" \
    "#!/bin/sh" \
    "node /var/lib/mempool/index.js" \
    > ./package/bin/cli.sh

chmod +x ./package/bin/cli.sh

$SU install -D -m 0660 -o mempool -g mempool ./mempool-config.sample.json /etc/mempool/mempool-config.json

$SU mv -f /tmp/mempool/backend/package /var/lib/mempool

$SU ln -s /var/lib/mempool /usr/lib/node_modules/mempool
$SU ln -s ../lib/node_modules/mempool/bin/cli.sh /usr/bin/mempool

Frontend

Install the frontend dependencies and build the project

cd /tmp/mempool/frontend
npm ci --omit=dev --omit=optional

Installation can take some time. There might be a lot of confusing output, but if you see something similar to the following, the installation was successful:

output

16 vulnerabilities (2 low, 4 moderate, 10 high)

To address issues that do not require attention, run:
  npm audit fix

To address all issues (including breaking changes), run:
  npm audit fix --force

Run `npm audit` for details.

⚠️

At 2024-08-31 there is at least 16 vulnerabilities not addressable without breaking changes

npm audit fix --force

Make it a global permanent installation

npm run build

$SU mv -f ./dist/mempool /var/www/

Cleanup

cd
rm -rf /tmp/mempool
$SU apk del .build-deps

Configuration

Check the configuration file and change highlighted values

$SU $EDITOR /etc/mempool/mempool-config.json

/etc/mempool/mempool-config.json

[...]
    "INDEXING_BLOCKS_AMOUNT": 52560,
[...]
    "STDOUT_LOG_MIN_PRIORITY": "info",
[...]
  "CORE_RPC": {
[...]
    "USERNAME": "",
    "PASSWORD": "",
[...]
    "COOKIE": true,
    "COOKIE_PATH": "/var/lib/bitcoind/.cookie"
  },
  "ESPLORA": {
    "REST_API_URL": "",
    "UNIX_SOCKET_PATH": "",
[...]
  "SECOND_CORE_RPC": {
    "HOST": "",
[...]
  "DATABASE": {
[...]
    "SOCKET": "/var/run/mysqld/mysqld.sock",
[...]
    "PASSWORD": "",
[...]
  "SOCKS5PROXY": {
    "ENABLED": true,
[...]

Redis

To use Redis caching, you need to install the redis package and configure the Mempool Space configuration file.

$SU apk add redis

/etc/mempool/mempool-config.json

[...]
  "REDIS": {
    "ENABLED": true,
    "UNIX_SOCKET_PATH": "/var/run/redis/redis.sock",
[...]

Remote access over Tor

To use your blockchain explorer when you’re on the go, you can easily create a Tor hidden service on the Microbolt and accessing the Mempool Space with the Tor browser from any device.

Add the following three lines in the “location-hidden services” section in the torrc file.

$SU $EDITOR /etc/tor/torrc

/etc/tor/torrc

# Hidden Service Mempool Space
HiddenServiceDir /var/lib/tor/mempool/
HiddenServiceVersion 3
HiddenServicePoWDefensesEnabled 1
HiddenServicePort 443 127.0.0.1:4081

Reload Tor configuration and get your connection address.

$SU rc-service tor reload
$SU cat /var/lib/tor/mempool/hostname

output

abcdefg..............xyz.onion

You should now be able to connect to your Mempool Space remotely via Tor using your hostname

Autostart on boot

Now we’ll make sure our blockchain explorer starts as a service on the computer so that it’s always running.

Create the Mempool Space init.d unit and copy/paste the following configuration. Save and exit.

$SU $EDITOR /etc/init.d/mempool

/etc/init.d/mempool

#!/sbin/openrc-run
 
: ${MEMPOOL_CONFIGFILE:=/etc/mempool/mempool-config.json}
: ${MEMPOOL_DATADIR:=/var/lib/mempool}
: ${MEMPOOL_LOGDIR:=/var/log/mempool}
: ${MEMPOOL_USER:=mempool}
: ${MEMPOOL_GROUP:=mempool}
: ${MEMPOOL_BIN:=/usr/bin/mempool}
: ${MEMPOOL_OPTS=${MEMPOOL_OPTS}}
: ${MEMPOOL_SIGTERM_TIMEOUT:=600}
 
MEMPOOL_PIDDIR="/run/mempool"
 
name="Mempool Space"
description="A self-hosted Bitcoin blockchain and mempool visualizer/explorer"
 
directory="${MEMPOOL_DATADIR}"
required_files="${MEMPOOL_CONFIGFILE}"
pidfile="${MEMPOOL_PIDDIR}/${SVCNAME}.pid"
retry="${MEMPOOL_SIGTERM_TIMEOUT}"
 
command="${MEMPOOL_BIN}"
command_args="${MEMPOOL_OPTS}"
command_user="${MEMPOOL_USER}:${MEMPOOL_GROUP}"
command_background="true"
 
start_stop_daemon_args="--env MEMPOOL_CONFIG_FILE=${MEMPOOL_CONFIGFILE}
                        --stdout ${MEMPOOL_LOGDIR}/debug.log
                        --stderr ${MEMPOOL_LOGDIR}/debug.log"
 
depend() {
    need bitcoind
    need mariadb
    checkdepend REDIS redis
 
    if service_started fulcrum; then
        need fulcrum
    elif service_started electrs; then
        need electrs
    else
        if service_exists fulcrum; then
            need fulcrum
        elif service_exists electrs; then
            need electrs
        else
            eerror "Neither fulcrum nor electrs is installed or started"
            return 1
        fi
    fi
}
 
checkdepend() {
    if sed -n '/^[[:space:]]*"'${1}'": {/,/^[[:space:]]*}/p' "${MEMPOOL_CONFIGFILE}" | grep -qs '"ENABLED": true'; then
        need "${2:-$1}"
    fi
}
 
service_exists() {
    rc-service --list | grep -q "^$1$"
}
 
start_pre() {
    checkpath --file      --mode 0660 --owner "${command_user}" "${MEMPOOL_CONFIGFILE}"
    checkpath --directory --mode 0750 --owner "${command_user}" "${MEMPOOL_DATADIR}"
    checkpath --directory --mode 0755 --owner "${command_user}" "${MEMPOOL_LOGDIR}"
    checkpath --directory --mode 0755 --owner "${command_user}" "${MEMPOOL_PIDDIR}"
}
 
stop() {
    ebegin "Stopping ${SVCNAME}"
    pkill -TERM -P "$(cat ${pidfile})" > /dev/null 2>&1
    start-stop-daemon \
        --stop \
        --pidfile="${pidfile}" \
        --retry="${MEMPOOL_SIGTERM_TIMEOUT}" \
        --exec="${MEMPOOL_BIN}"
    eend $?
}

Enable execution permission

$SU chmod +x /etc/init.d/mempool

Enable logrotate

Enter the complete next configuration. Save and exit

$SU $EDITOR /etc/logrotate.d/mempool

/etc/logrotate.d/mempool

/var/log/mempool/*.log {
    weekly
    missingok
    rotate 104
    compress
    delaycompress
    notifempty
    create 0640 mempool mempool
    sharedscripts
    postrotate
        killall -HUP `cat /run/mempool/mempool.pid`
    endscript
}

Test

$SU logrotate /etc/logrotate.d/mempool --debug

Enable and start Mempool Space

$SU rc-update add mempool

$SU rc-service mempool start

Check the log to see Mempool Space output. Exit with Ctrl-C

tail -f /var/log/mempool/debug.log

You can now access your own Mempool Space from within your local network by browsing to https://nakamoto01:4081 (or your equivalent IP address).

For the future: Mempool Space update

Follow again Mempool Space page replacing the environment variable VERSION=x.xx value for the latest if it has not been already changed in this guide.

Update the Mempool Space configuration if necessary (see release notes)

$SU $EDITOR /etc/mempool/mempool-config.json

Restart the service to apply the changes

$SU rc-service mempool restart

Blockchain explorer BTC RPC Explorer

Mempool Space

Preparations

Transaction indexing

Install dependencies

Create the mempool user/group

Add mempool user to the bitcoin group

Add satoshi user to the mempool group

Reverse proxy

Firewall

Installation

Download source code

Signature check

MariaDB

Backend

Frontend

Cleanup

Configuration

Autostart on boot

Enable logrotate

Enable and start Mempool Space

For the future: Mempool Space update

Create the `mempool` user/group

Add `mempool` user to the `bitcoin` group

Add `satoshi` user to the `mempool` group