Running ephemeral and isolated sandboxes can be useful to experiment with faster networks or to automate reproducible tests.

Here we use Flextesa to run one or more Tezos nodes, bakers, and endorsers contained in a sandbox environment. The default sandbox is configured to be compatible with the tezos-client installed in the “Client-setup” section.


This example requires Docker, available for Linux, Mac or Windows at

Starting and Using a Sandbox

Start the sandbox in the background (will run with baking enabled):

docker run --rm --name my-sandbox --detach -p 20000:20000 \ babylonbox start

After a few seconds this should succeed:

tezos-client -A localhost -P 20000 bootstrapped

Configure the client to communicate with the sandbox:

tezos-client -A localhost -P 20000 config update

Then, instead of using a public faucet one can just use ꜩ by importing accounts already existing in the sandbox. They are visible with:

$ docker run --rm babylonbox info
Usable accounts:
- alice
* edpkvGfYw3LyB1UcCahKQk4rF2tvbMUk8GFiTuMjL75uGXrpvKXhjn
* tz1VSUr8wwNhLAzempoch5d6hLRiTh8Cjcjb
* unencrypted:edsk3QoqBuvdamxouPhin7swCvkQNgq4jP5KZPbwWNnwdZpSpJiEbq
- bob
* edpkurPsQ8eUApnLUJ9ZPDvu98E8VNj4KtJa1aZr16Cr5ow5VHKnz4
* tz1aSkwEot3L2kmUvcoxzjMomb9mvBNuzFK6
* unencrypted:edsk3RFfvaFaxbHx8BMtEW1rKQcPtDML3LXjNqMNLCzC3wLC1bWbAt
Root path (logs, chain data, etc.): /tmp/mini-box (inside container).

You may then just import them:

tezos-client import secret key alice unencrypted:edsk3QoqBuvdamxouPhin7swCvkQNgq4jP5KZPbwWNnwdZpSpJiEbq --force
tezos-client import secret key bob unencrypted:edsk3RFfvaFaxbHx8BMtEW1rKQcPtDML3LXjNqMNLCzC3wLC1bWbAt --force

Check their balances:

tezos-client get balance for alice

Using The Sandbox

See also the Quickstart section or the Wallet-usage tutorial of the Tezos manual.

For instance, one can originate the most minimalistic contract:

# Download the contract:
# Run origination:
tezos-client originate contract hello-id transferring 0 from bob running --init "\"hello world\"" --burn-cap 1 --force

Shutting Down The Sandbox

When you're done playing, just destroy the container:

docker kill my-sandbox

Advanced Usage

One can see the configuration of the protocol running in the sandbox with:

tezos-client rpc get /chains/main/blocks/head/context/constants

One important field is "time_between_blocks": [ "5" ], which means that blocks are baked every 5 seconds (as opposed to 60 seconds on Mainnet).

This constant can be configured with the block_time environment variable (see example below).

Many other parameters are set by the babylonbox script. All the configuration options available can be seen with the command:

docker run --rm -it flextesarl mini-net --help

The docker image also provides a carthagebox script, which runs the protocol currently being voted on instead of Babylon:

docker run --rm --name my-sandbox -e block_time=10 --detach -p 20000:20000 \ carthagebox start

The above command runs a full sandbox with the Carthage protocol and a slower time-between-blocks of 10 seconds.

For more issues or questions, see the Flextesa repository.