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Groestlcoin Esplora Block Explorer

docker release MIT license Pull Requests Welcome

Block explorer web interface based on the electrs HTTP API (see blockstream branch).

Written as a single-page app in a reactive and functional style using rxjs and cycle.js.

See live at

API documentation is available here.

Join the translation efforts on Transifex.



  • Explore blocks, transactions and addresses

  • Support for Segwit and Bech32 addresses

  • Shows previous output and spending transaction details

  • Quick-search for txid, address, block hash or height by navigating to /<query>

  • Advanced view with script hex/assembly, witness data, outpoints and more

  • Mobile-ready responsive design

  • Translated to 17 languages

  • Light and dark themes

  • Noscript support

  • Mainnet, Testnet and signet high performance electrum server


To start a development server with live babel/browserify transpilation, run:

$ git clone && cd esplora
$ npm install
$ export API_URL=http://localhost:3000/ # or if you don't have a local API server
# (see more config options below)
$ npm run dev-server

The server will be available at http://localhost:5000/

To display debugging information for the Rx streams in the web developer console, set localStorage.debug = '*' and refresh.


To build the static assets directory for production deployment, set config options (see below) and run $ npm run dist. The files will be created under dist/.

Because Esplora is a single-page app, the HTTP server needs to be configured to serve the index.html file in reply to missing pages. See contrib/ for example nginx configuration (TL;DR: try_files $uri /index.html).

Pre-rendering server (noscript)

To start a pre-rendering server that generates static HTML replies suitable for noscript users, run:

# (clone, cd, "npm install" and configure as above)

$ export STATIC_ROOT=http://localhost:5000/ # for loading CSS, images and fonts
$ npm run prerender-server

The server will be available at http://localhost:5001/

Configuration options

All options are optional.

GUI options

  • NODE_ENV - set to production to enable js minification, or to development to disable (defaults to production)
  • BASE_HREF - base href for user interface (defaults to /, change if not served from the root directory)
  • STATIC_ROOT - root for static assets (defaults to BASE_HREF, change to load static assets from a different server)
  • API_URL - URL for HTTP REST API (defaults to /api, change if the API is available elsewhere)
  • CANONICAL_URL - absolute base url for user interface (optional, only required for opensearch and canonical link tags)
  • NATIVE_ASSET_LABEL - the name of the network native asset (defaults to GRS)
  • SITE_TITLE - website title for <title> (defaults to Groestlcoin Esplora)
  • SITE_DESC - meta description (defaults to Groestlcoin Esplora Block Explorer)
  • HOME_TITLE - text for homepage title (defaults to SITE_TITLE)
  • SITE_FOOTER - text for page footer (defaults to Powered by esplora)
  • HEAD_HTML - custom html to inject at the end of <head>
  • FOOT_HTML - custom html to inject at the end of <body>
  • CUSTOM_ASSETS - space separated list of static assets to add to the build
  • CUSTOM_CSS - space separated list of css files to append into style.css
  • NOSCRIPT_REDIR - redirect noscript users to {request_path}?nojs (should be captured server-side and redirected to the prerender server, also see NOSCRIPT_REDIR_BASE in dev server options)

Note that API_URL should be set to the publicly-reachable URL where the user's browser can issue requests at. (that is, not via localhost, unless you're setting up a dev environment where the browser is running on the same machine as the API server.)

Elements-only configuration:

  • IS_ELEMENTS - set to 1 to indicate this is an Elements-based chain (enables asset issuance and peg features)
  • NATIVE_ASSET_ID - the ID of the native asset used to pay fees (defaults to 6f0279e9ed041c3d710a9f57d0c02928416460c4b722ae3457a11eec381c526d, the asset id for BTC)
  • BLIND_PREFIX - the base58 address prefix byte used for confidential addresses (defaults to 12)
  • PARENT_CHAIN_EXPLORER_TXOUT - URL format for linking to transaction outputs on the parent chain, with {txid} and {vout} as placeholders. Example:{txid}#output:{vout}
  • PARENT_CHAIN_EXPLORER_ADDRESS - URL format for linking to addresses on parent chain, with {addr} replaced by the address. Example:{addr}
  • ASSET_MAP_URL - url to load json asset map (in the "minimal" format)

Menu configuration (useful for inter-linking multiple instances on different networks):

  • MENU_ITEMS - json map of menu items, where the key is the label and the value is the url
  • MENU_ACTIVE - the active menu item identified by its label

Development server options

All GUI options, plus:

  • PORT - port to bind http development server (defaults to 5000)
  • CORS_ALLOW - value to set for Access-Control-Allow-Origin header (optional)
  • NOSCRIPT_REDIR_BASE - base url for prerender server, for redirecting ?nojs requests (should be set alongside NOSCRIPT_REDIR)

Pre-rendering server options

All GUI options, plus:

  • PORT - port to bind pre-rendering server (defaults to 5001)

Note that unlike the regular JavaScript-based app that sends API requests from the client-side, the pre-rendering server sends API requests from the server-side. This means that API_URL should be configured to the URL reachable by the server, typically http://localhost:3000/.

How to build the Docker image

docker build -t esplora .

How to run the explorer for Groestlcoin mainnet

docker run -p 50001:50001 -p 8080:80 \
           --volume $PWD/data_bitcoin_mainnet:/data \
           --rm -i -t esplora \
           bash -c "/srv/explorer/ bitcoin-mainnet explorer"

How to run the explorer for Groestlcoin testnet3

docker run -p 50001:50001 -p 8084:80 \
           --volume $PWD/data_bitcoin_testnet:/data \
           --rm -i -t esplora \
           bash -c "/srv/explorer/ bitcoin-testnet explorer"

How to run the explorer for Groestlcoin signet

docker run -p 50001:50001 -p 8084:80 \
           --volume $PWD/data_bitcoin_signet:/data \
           --rm -i -t esplora \
           bash -c "/srv/explorer/ bitcoin-signet explorer"

How to run the explorer for Groestlcoin regtest

docker run -p 50001:50001 -p 8094:80 \
           --volume $PWD/data_bitcoin_regtest:/data \
           --rm -i -t esplora \
           bash -c "/srv/explorer/ bitcoin-regtest explorer"

Regtest options

When run for Groestlcoin regtest, the esplora container will create a default wallet and mine 100 blocks internally. You can disable this behavior by setting NO_REGTEST_MINING=1.

Docker config options

Set -e DEBUG=verbose to enable more verbose logging.

Set -e NO_PRECACHE=1 to disable pre-caching of statistics for "popular addresses", which may take a long time and is not necessary for personal use.

Set -e NO_ADDRESS_SEARCH=1 to disable the by-prefix address search index.

Set -e ENABLE_LIGHTMODE=1 to enable esplora-electrs's light mode.

Set -e ONION_URL=http://xyz.onion to enable the Onion-Location header.

Build new esplora-base

docker build -t Groestlcoin/esplora-base:latest -f Dockerfile.deps .
docker push Groestlcoin/esplora-base:latest
docker inspect --format='{{index .RepoDigests 0}}' Groestlcoin/esplora-base

Build new tor (or you can pull directly from Docker Hub - blockstream/tor:latest)

docker build --squash -t blockstream/tor:latest -f Dockerfile.tor .
docker push blockstream/tor:latest
docker inspect --format='{{index .RepoDigests 0}}' blockstream/tor

Run: docker -d --name hidden_service blockstream/tor:latest tor -f /home/tor/torrc (could add a -v /extra/torrc:/home/tor/torrc, if you have a custom torrc)

Example torrc:

DataDirectory /home/tor/tor
PidFile /var/run/tor/

ControlSocket /var/run/tor/control GroupWritable RelaxDirModeCheck
ControlSocketsGroupWritable 1
SocksPort unix:/var/run/tor/socks WorldWritable
SocksPort 9050

CookieAuthentication 1
CookieAuthFileGroupReadable 1
CookieAuthFile /var/run/tor/control.authcookie

Log [handshake]debug [*]notice stderr

HiddenServiceDir /home/tor/tor/hidden_service_v3/
HiddenServiceVersion 3
HiddenServicePort 80




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