Table of contents
Introduction
The 0x API is a collection of services and endpoints that can be run together or separately. In aggregate, the APIs provide interfaces to 0x liquidity.
Everything can be run monolithically via yarn start
and docker-compose
up as described in Getting Started.
Services
The API contains different services that serve a collection of HTTP or websocket endpoints and keep your order states in sync with the Ethereum state.
HTTP Services
These are services that handle HTTP requests and responses.
Name | Path | Run Command | Requires Ethereum JSON RPC Provider? | Requires Relational Database? |
---|---|---|---|---|
All HTTP Services | /* |
yarn start:service:http |
Yes | Yes |
Swap | /swap |
yarn start:service:swap_http |
Yes | Yes |
Orderbook | /orderbook |
yarn start:service:sra_http |
No | Yes |
Meta Transaction Service | /meta_transaction |
yarn start:service:meta_transaction_http |
Yes | Yes |
Data Services
The transaction watcher ensures that the data being served is present and up-to-date by keeping the database in sync with Ethereum. The endpoints above run without it, but would be providing degraded or non-functional service.
Name | Run Command | Requires Ethereum JSON RPC Provider? | Requires Relational Database? |
---|---|---|---|
Transaction Watcher (monitor and broadcast meta transactions) | yarn start:service:transaction_watcher |
Yes | Yes |
Getting started
Pre-requirements
Developing
To get a local development version of 0x-api
running:
-
Clone the repo.
-
Create an
.env
file and copy the content from the.env_example
file. Defaults are defined inconfig.ts
/config.js
. The bash environment takes precedence over the.env
file. If you runsource .env
, changes to the.env
file will have no effect until you unset the colliding variables.
Environment Variable | Default | Description |
---|---|---|
CHAIN_ID |
Required. No default. | The chain id you'd like your API to run on (e.g: 1 -> mainnet, 42 -> Kovan, 3 -> Ropsten, 1337 -> Ganache). Defaults to 42 in the API, but required for docker-compose up . |
ETHEREUM_RPC_URL |
Required. No default. | The URL used to issue JSON RPC requests. Use http://localhost:8545 to use the local ganache instance. |
LIQUIDITY_POOL_REGISTRY_ADDRESS |
Optional. No default | The Ethereum address of a Liquidity Provider registry. If unspecified, no Liquidity Provider is used. |
POSTGRES_URI |
Required. Default for dev: postgresql://api:api@localhost/api |
A URI of a running postgres instance. By default, the API will create all necessary tables. A default instance is spun up in docker-compose up |
POSTGRES_READ_REPLICA_URIS |
Optional. No default | A comma separated list of URIs of running postgres read replica instances. |
FEE_RECIPIENT_ADDRESS |
0x0000000000000000000000000000000000000000 |
The Ethereum address which should be specified as the fee recipient in orders your API accepts. |
MAKER_FEE_ASSET_DATA |
0x |
The maker fee token asset data for created 0x orders. |
TAKER_FEE_ASSET_DATA |
0x |
The taker fee token asset data for created 0x orders. |
MAKER_FEE_UNIT_AMOUNT |
0 |
The flat maker fee amount you'd like to receive for filled orders hosted by you. |
TAKER_FEE_UNIT_AMOUNT |
0 |
The flat taker fee amount you'd like to receive for filled orders hosted by you. |
WHITELIST_ALL_TOKENS |
false |
A boolean determining whether all tokens should be allowed to be posted. |
SWAP_IGNORED_ADDRESSES |
[] |
A comma separated list of addresses to ignore. These addresses are persisted but not used in any /swap/* endpoints |
META_TXN_SUBMIT_WHITELISTED_API_KEYS |
[] |
A comma separated list of whitelisted 0x API keys that can use the meta-txn /submit endpoint. |
META_TXN_RELAY_PRIVATE_KEYS |
[] |
A comma separated list of meta-txn relay sender private keys managed by the TransactionWatcherSignerService. |
META_TXN_SIGNING_ENABLED |
true |
A boolean determining whether the meta-txn signs and submits transactions . |
META_TXN_MAX_GAS_PRICE_GWEI |
50 |
The maximum gas price (in gwei) the meta-txn service will submit a transaction at. If the gas price of the network exceeds this value then the meta-txn service will be disabled. |
META_TXN_RELAY_EXPECTED_MINED_SEC |
Default: 120 |
The expected time for a meta-txn to be included in a block. |
ENABLE_PROMETHEUS_METRICS |
Default: false |
A boolean determining whether to enable prometheus monitoring. |
PROMETHEUS_PORT |
Default: 8080 |
The port from which prometheus metrics should be served. |
KAFKA_BROKERS |
Optional. No default. | A comma separated list of Kafka broker servers |
KAFKA_TOPIC_QUOTE_REPORT |
Optional. No default | The name of the Kafka topic to publish quote reports on. Setting this and KAFKA_BROKERS enable publirhing. |
-
Install the dependencies:
yarn
-
Build the project:
yarn build
-
Run
docker-compose up
to run the other dependencies required for the API. This uses the localdocker-compose.yml
file. -
Run the database migrations:
yarn db:migrate
-
Start the API
yarn start
For development:
yarn dev
Developing on Ganache
To use ganache, use the .env
file below:
CHAIN_ID=1337
ETHEREUM_RPC_URL=http://localhost:8545
Then run
$ docker-compose up
$ yarn dev
Testing
Run yarn test
. It's really that easy :)
Tip: Test suites set up and teardown sandboxed environments, so using .only
on it
and describe
statements will save lots of development time.
Commands
yarn build
- Build the codeyarn test
- Test the codeyarn lint
- Lint the codeyarn start
- Starts the APIyarn dev
- Starts the API in dev-modeyarn watch
- Watch the source code and rebuild on changeyarn prettier
- Auto-format the codeyarn release
- Release a new version of the 0x-api
Deployment
A Docker image is built and hosted by Dockerhub every time a change to the master
branch occurs. A Docker image is built, pushed and tagged when a new version is released as well.
Running this image will run 0x API as a monolith, with all its dependencies. You can run any of the services separately by overriding the Docker command with the service-specific command when running the container.
When versioning the API, we freeze the old version in a separate branch so that we can deploy patches, and continue to support the old version until it's officially deprecated. Be aware when contributing fixes that you may want to apply the fix to an older version too.
This is a list of endpoints supported by different versions of the API. If an endpoint is not on this list, it is by default pointed to the master branch.
Endpoint(s) | API version branch | @0x/asset-swapper branch |
---|---|---|
/swap/v0/ , /meta_transaction/v0 |
https://github.com/0xProject/0x-api/tree/freeze/swap-v0 | https://github.com/0xProject/0x-monorepo/tree/v0-asset-swapper |
/sra/v3 |
https://github.com/0xProject/0x-api/tree/freeze/sra-v3 | N/A |
Release
Releases are triggered automatically by the release GitHub action.
They can also be triggered manually by using yarn release
, which requires a GITHUB_TOKEN environment variable.
Database
This project uses TypeORM. It makes it easier for anyone to switch out the backing database used by this project. By default, this project uses a PostgreSQL database.
To add a migration, you may use the following command:
yarn db:migration:create -n myMigration
Legal Disclaimer
The laws and regulations applicable to the use and exchange of digital assets and blockchain-native tokens, including through any software developed using the licensed work created by ZeroEx Intl. as described here (the “Work”), vary by jurisdiction. As set forth in the Apache License, Version 2.0 applicable to the Work, developers are “solely responsible for determining the appropriateness of using or redistributing the Work,” which includes responsibility for ensuring compliance with any such applicable laws and regulations. See the Apache License, Version 2.0 for the specific language governing all applicable permissions and limitations: http://www.apache.org/licenses/LICENSE-2.0