How to build and run

Get the sources

Tezos git repository is hosted at GitLab. All development happens here. Do not use our GitHub mirror which we don’t use anymore and only mirrors what happens at GitLab.

You also need to choose a branch:

  • The master branch is where code is merged, but there is no test network using the master branch directly.
  • The alphanet and alphanet-lmdb is what you want to use if you want to connect to Tezos’ test network, the Alphanet. The -lmdb version uses LMDB instead of LevelDB.

TL;DR: Typically you want to do:

git clone
git checkout alphanet

Install OPAM

To compile Tezos, you need an OCaml compiler (version 4.06.1) and all the libraries listed in the various tezos-*.opam files.

The simplest way to install all dependencies is by using OPAM, the OCaml package manager.

IMPORTANT: Please use version 2 of OPAM. That is what the Tezos Core team uses. Most distribution probably ship version 1 of OPAM out of the box, but installing version 2 is preferable for many reasons.

Then, you need to create a new switch alias for Tezos. A switch is your own version of the OPAM configuration, including the OCaml compiler, all packages, and package manager configuration related to your project. This is necessary so that the project doesn’t conflict with other OCaml projects or other versions of Tezos.

opam update
opam switch create tezos 4.06.1
eval $(opam env)

If you are stuck with OPAM1:

opam update
opam switch tezos --alias-of 4.06.1
eval $(opam config env)

The last command-line activates the switch.

Note that if you previously created a switch named tezos but with an older OCaml version you need to remove the switch with opam switch remove tezos.

Install Tezos dependencies with OPAM

Install the libraries which Tezos depends on:

make build-deps

While building the dependencies, opam is able to handle correctly the OCaml libraries but it is not always able to handle all external C libraries we depend on. On most system, it is able to suggest a call to the system package manager but it currently does not handle version check.

At last, compile the project:


This should produce three binaries:

  • tezos-node: the tezos daemon itself;
  • tezos-client: a command-line client;
  • tezos-admin-client: a command-line administration tool for the node;
  • tezos-alpha-baker: a client and daemon to bake on the Tezos network;
  • tezos-protocol-compiler: a protocol compiler used for developing new version of the economic protocol.

Currently Tezos is being developed for Linux only. It should work on macOS, but it has not been tested recently. A Windows port is feasible and might be developed in the future.

Note that, when executing make build-deps, OPAM will detect if required system dependencies are installed. However, it is not able to detect which versions you actually have.

If after a git pull, the build fails (either at make build-deps or make), you might try to clean up a little bit the opam internal state with the following commands:

opam update
opam pin list -s | xargs opam pin remove
make build-deps

Join the Alphanet!

If you succesfully built Tezos on the alphanet or alphanet-lmdb branch, then your node is elligible to join Tezos’ Alphanet.

Command-line basics

The tezos-node executable uses subcommands. You can obtain help on a subcommand by using ./tezos-node <subcommand> –help. There are three subcommands:

./tezos-node identity --help
./tezos-node config --help
./tezos-node run --help

The identity and config serve the purpose of managing configuration files for the node, we will describe them below. The run command is for running the node.

Pretty much all configuration parameters can be overriden by a command-line argument. Check out ./tezos-node run –help to discover them.

Configure your node

The following steps are required to connect to Alphanet.

./tezos-node identity generate

This will generate a new node identity and compute the associated stamp of proof-of-work. The identity comprises a pair of cryptographic keys that nodes use to encrypt messages sent to each other, and an antispam-PoW stamp proving that enough computing power has been dedicated to creating this identity.

The identity will be stored in $HOME/.tezos-node/identity.json.

./tezos-node config init

This will initialize an configuration file for the node in $HOME/.tezos-node/config.json, using default values. It only specifies that the node will listen to incoming connections on socket address [::]:9732.

The easiest way to amend this default configuration is to use

# Update the config file
./tezos-node config update <…>
# Start from an empty cfg file
./tezos-node config reset <…>

All blockchain data is stored under $HOME/.tezos-node/. You can change this by doing ./tezos-node config update –data-dir </somewhere/in/your/disk>.

To run multiple nodes on the same machine, you can duplicate and edit $HOME/.tezos-node/config.json while making sure they don’t share the same data-dir. Then run your node with ./tezos-node run –config-file=</path/to/alternate_cfg>.

Lastly, you want to enable RPC communication with clients. Use:

./tezos-node config update --rpc-addr=

This is the default socket address that the client will try, so ./tezos-client will work out-of-the-box that way.

Run your node

You are all set! Now you just need to do:

./tezos-node run

To interact with your node, read the doc of clients:

./tezos-client man
./tezos-admin-client man
./tezos-alpha-baker man

And read this page to get alphanet tezzies.

Use sandboxed mode

To run a ‘localhost-only’ instance of a Tezos network, we provide two helper scripts:

  • ./src/bin_node/
  • ./src/bin_client/

Run a sandboxed node

For instance, if you want to run local network with two nodes, in a first terminal, the following command will initialize a node listening for peers on port 19731 and listening for RPC on port 18731.

./src/bin_node/ 1

This node will store its data in a temporary directory which will be removed when the node is killed.

To launch the second node, just run the following command, it will listen on port 19739 and 18739:

./src/bin_node/ 9

You might replace 1 or 9 by any number in between if you want to run more than two nodes. But, if you intend to run a single node network, you might remove the spurious “Too few connections” warnings by lowering the number of expected connection, by running the following command instead:

./src/bin_node/ 1 --connections 0

Use the sandboxed client

Once your node(s) is/are running, open a new terminal and initialize the “sandboxed” client data:

eval `./src/bin_client/ 1`

It will initialize the client data in a temporary directory. It will also defines in the current shell session an alias tezos-client preconfigured for communicating the same-numbered node. For instance:

$ tezos-client rpc get /chains/main/blocks/head/hash
{ "hash": "BLockGenesisGenesisGenesisGenesisGenesisGeneskvg68z" }

When you bootstrap a new network, the network is initialized with a dummy economic protocol, called “genesis”. If you want to run the same protocol than the alphanet, init-sandboxed-client also defines an alias tezos-activate-alpha, that you need to execute once for activating the whole network. For instance:

$ tezos-client rpc get /chains/main/blocks/head/metadata/next_protocol_hash
{ "protocol": "ProtoGenesisGenesisGenesisGenesisGenesisGenesk612im" }
$ tezos-activate-alpha
Injected BMBcK869jaHQDc
$ tezos-client rpc get /chains/main/blocks/head/metadata/next_protocol_hash
{ "protocol": "ProtoALphaALphaALphaALphaALphaALphaALphaALphaDdp3zK" }

Tune protocol alpha parameters

The tezos-active-alpha alias use parameters from scripts/protocol_parameters.json to activate protocol alpha. It can be useful to tune these parameters when you need to debug something, for example, change the number of blocks per cycle, the time between blocks, etc.

Configuration options

Here is an example configuration file with all parameters specified. Most of the time it uses default values, except for cases where the default is not explanatory enough (i.e. “bootstrap-peers” is an empty list by default). Comments are not allowed in JSON, so this configuration file would not parse. They are just provided here to help writing your own configuration file if needed.


  /* Location of the data dir on disk. */

  "data-dir": "/home/tezos/my_data_dir"

  /* Configuration of net parameters */

  "net": {

    /* Floating point number between 0 and 256 that represents a
    difficulty, 24 signifies for example that at least 24 leading
    zeroes are expected in the hash. */

    "expected-proof-of-work": 24.5,

    /* List of hosts. Tezos can connect to both IPv6 and IPv4
    hosts. If the port is not specified, default port 9732 will be
    assumed. */

    "bootstrap-peers": ["::1:10732", "::ffff:", ""],

    /* Specify if the node is in private mode or not. A node in
    private mode only opens outgoing connections to peers whose
    addresses are in [trusted_peers] and only accepts incoming
    connections from trusted peers. In addition, it informs these
    peers that the identity of the node should not be revealed to
    the rest of the network. */

    "private-mode": false,

    /* Network limits */

    "limits": {

      /* Delay granted to a peer to perform authentication, in
      seconds. */

      "authentication-timeout": 5,

      /* Strict minimum number of connections (triggers an urgent
      maintenance). */

      "min-connections": 50,

      /* Targeted number of connections to reach when bootstraping /
      maintaining. */

      "expected-connections": 100,

      /* Maximum number of connections (exceeding peers are
      disconnected). */

      "max-connections": 200,

      /* Number above which pending incoming connections are
      immediately rejected. */

      "backlog": 20,

      /* Maximum allowed number of incoming connections that are
      pending authentication. */

      "max-incoming-connections": 20,

      /* Max download and upload speeds in KiB/s. */

      "max-download-speed": 1024,
      "max-upload-speed": 1024,

      /* Size of the buffer passed to read(2). */

      "read-buffer-size": 16384,

  /* Configuration of rpc parameters */

  "rpc": {

    /* Host to listen to. If the port is not specified, the default
    port 8732 will be assumed. */

    "listen-addr": "localhost:8733",

    /* Cross Origin Resource Sharing parameters, see */

    "cors-origin": [],
    "cors-headers": [],

    /* Certificate and key files (necessary when TLS is used). */

    "crt": "tezos-node.crt",
    "key": "tezos-node.key"

  /* Configuration of log parameters */

  "log": {

    /* Output for the logging function. Either "stdout", "stderr" or
    the name of a log file . */

    "output": "tezos-node.log",

    /* Verbosity level: one of 'fatal', 'error', 'warn', 'notice',
    'info', 'debug'. */

    "level": "info",

    /* Fine-grained logging instructions. Same format as described in
    `tezos-node run --help`, DEBUG section. In the example below,
    sections "net" and all sections starting by "client" will have
    their messages logged up to the debug level, whereas the rest of
    log sections will be logged up to the notice level. */

    "rules": "client* -> debug, net -> debug, * -> notice",

    /* Format for the log file, see */

    "template": "$(date) - $(section): $(message)"

  /* Configuration for the validator and mempool parameters */

  "shell": {

     /* The number of peers to synchronize with
        before declaring the node 'bootstrapped'. */

     "bootstrap_threshold": 4



It is possible to set independent log levels for different logging sections in Tezos, as well as specifying an output file for logging. See the description of log parameters above as well as documentation under the DEBUG section displayed by tezos-node run –-help.

JSON/RPC interface

The Tezos node provides a JSON/RPC interface. Note that it is an RPC, and it is JSON based, but it does not follow the “JSON-RPC” protocol. It is not active by default and it must be explicitly activated with the --rpc-addr option. Typically, if you are not trying to run a local network and just want to explore the RPC, you would run:

./tezos-node run --rpc-addr localhost

The RPC interface is self-documented and the tezos-client executable is able to pretty-print the RPC API. For instance, to see the API provided by the Tezos Shell:

./tezos-client rpc list

To get API attached to the “genesis” block, including the remote procedures provided by the associated economic protocol version:

./tezos-client rpc list /blocks/genesis/

You might also want the JSON schema describing the expected input and output of a RPC. For instance:

./tezos-client rpc schema /blocks/genesis/hash

Note: you can get the same information, but as a raw JSON object, with a simple HTTP request:

wget --post-data '{ "recursive": true }' -O - http://localhost:8732/describe
wget --post-data '{ "recursive": true }' -O - http://localhost:8732/describe/blocks/genesis
wget -O - http://localhost:8732/describe/blocks/genesis/hash

The minimal CLI client

Tezos is distributed with two command line tools: a minimal command line wallet tezos-client, and an administration tool tezos-admin-client.

Their command line interfaces are described here and here.