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Standard Relayer REST API Client

Project description


A Python client for interacting with servers conforming to the Standard Relayer API specification.

Read the documentation


The JSON schemas for the API payloads and responses can be found in @0xproject/json-schemas. Examples of each payload and response can be found in the 0x.js library's test suite.

pip install 0x-json-schemas

You can easily validate your API's payloads and responses using the 0x-json-schemas package:

from zero_ex.json_schemas import assert_valid
from zero_ex.order_utils import Order

order: Order = {
    'makerAddress': "0x0000000000000000000000000000000000000000",
    'takerAddress': "0x0000000000000000000000000000000000000000",
    'feeRecipientAddress': "0x0000000000000000000000000000000000000000",
    'senderAddress': "0x0000000000000000000000000000000000000000",
    'makerAssetAmount': "1000000000000000000",
    'takerAssetAmount': "1000000000000000000",
    'makerFee': "0",
    'takerFee': "0",
    'expirationTimeSeconds': "12345",
    'salt': "12345",
    'makerAssetData': "0x0000000000000000000000000000000000000000",
    'takerAssetData': "0x0000000000000000000000000000000000000000",
    'exchangeAddress': "0x0000000000000000000000000000000000000000",

assert_valid(order, "/orderSchema")


Requests that return potentially large collections should respond to the ?page and ?perPage parameters. For example:

$ curl

Page numbering should be 1-indexed, not 0-indexed. If a query provides an unreasonable (ie. too high) perPage value, the response can return a validation error as specified in the errors section. If the query specifies a page that does not exist (ie. there are not enough records), the response should just return an empty records array.

All endpoints that are paginated should return a total, page, perPage and a records value in the top level of the collection. The value of total should be the total number of records for a given query, whereas records should be an array representing the response to the query for that page. page and perPage, are the same values that were specified in the request. See the note in miscellaneous about formatting snake_case vs. lowerCamelCase.

These requests include the /v2/asset_pairs, /v2/orders, /v2/fee_recipients and /v2/orderbook endpoints.

Network Id

All requests should be able to specify a ?networkId query param for all supported networks. For example:

$ curl

If the query param is not provided, it should default to 1 (mainnet).

Networks and their Ids:

Network Id Network Name
1 Mainnet
42 Kovan
3 Ropsten
4 Rinkeby

If a certain network is not supported, the response should 400 as specified in the error response section. For example:

    \"code\": 100,
    \"reason\": \"Validation failed\",
    \"validationErrors\": [
            \"field\": \"networkId\",
            \"code\": 1006,
            \"reason\": \"Network id 42 is not supported\"

Link Header

A Link Header can be included in a response to provide clients with more context about paging For example:

Link: <>; rel=\"next\",
<>; rel=\"last\"

This Link response header contains one or more Hypermedia link relations.

The possible rel values are:

Name Description
next The link relation for the immediate next page of results.
last The link relation for the last page of results.
first The link relation for the first page of results.
prev The link relation for the immediate previous page of results.

Rate Limits

Rate limit guidance for clients can be optionally returned in the response headers:

Header Name Description
X-RateLimit-Limit The maximum number of requests you're permitted to make per hour.
X-RateLimit-Remaining The number of requests remaining in the current rate limit window.
X-RateLimit-Reset The time at which the current rate limit window resets in UTC epoch seconds.

For example:

$ curl -i
HTTP/1.1 200 OK
Date: Mon, 20 Oct 2017 12:30:06 GMT
Status: 200 OK
X-RateLimit-Limit: 60
X-RateLimit-Remaining: 56
X-RateLimit-Reset: 1372700873

When a rate limit is exceeded, a status of 429 Too Many Requests should be returned.


Unless the spec defines otherwise, errors to bad requests should respond with HTTP 4xx or status codes.

Common error codes

Code Reason
400 Bad Request – Invalid request format
404 Not found
429 Too many requests - Rate limit exceeded
500 Internal Server Error
501 Not Implemented

Error reporting format

For all 400 responses, see the error response schema.

    \"code\": 101,
    \"reason\": \"Validation failed\",
    \"validationErrors\": [
            \"field\": \"maker\",
            \"code\": 1002,
            \"reason\": \"Invalid address\"

General error codes:

100 - Validation Failed
101 - Malformed JSON
102 - Order submission disabled
103 - Throttled

Validation error codes:

1000 - Required field
1001 - Incorrect format
1002 - Invalid address
1003 - Address not supported
1004 - Value out of range
1005 - Invalid signature or hash
1006 - Unsupported option

Asset Data Encoding

As we now support multiple token transfer proxies, the identifier of which proxy to use for the token transfer must be encoded, along with the token information. Each proxy in 0x v2 has a unique identifier. If you're using 0x.js there will be helper methods for this encoding and decoding.

The identifier for the Proxy uses a similar scheme to ABI function selectors.

// ERC20 Proxy ID  0xf47261b0
// ERC721 Proxy ID 0x02571792

Asset data is encoded using ABI encoding.

For example, encoding the ERC20 token contract (address: 0x1dc4c1cefef38a777b15aa20260a54e584b16c48) using the ERC20 Transfer Proxy (id: 0xf47261b0) would be:


Encoding the ERC721 token contract (address: 0x371b13d97f4bf77d724e78c16b7dc74099f40e84), token id (id: 99, which hex encoded is 0x63) and the ERC721 Transfer Proxy (id: 0x02571792) would be:


For more information see the Asset Proxy section of the v2 spec and the Ethereum ABI Spec.

Meta Data in Order Responses

In v2 of the standard relayer API we added the metaData field. It is meant to provide a standard place for relayers to put optional, custom or non-standard fields that may of interest to the consumer of the API.

A good example of such a field is remainingTakerAssetAmount, which is a convenience field that communicates how much of a 0x order is potentially left to be filled. Unlike the other fields in a 0x order, it is not guaranteed to be correct as it is derived from whatever mechanism the implementer (ie. the relayer) is using. While convenient for prototyping and low stakes situations, we recommend validating the value of the field by checking the state of the blockchain yourself.


  • All requests and responses should be of application/json content type
  • All token amounts are sent in amounts of the smallest level of precision (base units). (e.g if a token has 18 decimal places, selling 1 token would show up as selling '1000000000000000000' units by this API).
  • All addresses are sent as lower-case (non-checksummed) Ethereum addresses with the 0x prefix.
  • All parameters are to be written in lowerCamelCase.

This Python package is automatically generated by the OpenAPI Generator project:

  • API version: 2.0.0
  • Package version: 1.0.0
  • Build package: org.openapitools.codegen.languages.PythonClientCodegen


Python 2.7 and 3.4+

Installation & Usage

pip install

If the python package is hosted on Github, you can install directly from Github

pip install git+

(you may need to run pip with root permission: sudo pip install git+

Then import the package:

import sra_client


Install via Setuptools.

python install --user

(or sudo python install to install the package for all users)

Then import the package:

import sra_client

Getting Started

Please follow the installation procedure and then run the following:

from __future__ import print_function
import time
import sra_client
from import ApiException
from pprint import pprint

# create an instance of the API class
api_instance = sra_client.DefaultApi(sra_client.ApiClient(configuration))
asset_data_a = 0xf47261b04c32345ced77393b3530b1eed0f346429d # str | The assetData value for the first asset in the pair. (optional)
asset_data_b = 0x0257179264389b814a946f3e92105513705ca6b990 # str | The assetData value for the second asset in the pair. (optional)
network_id = 42 # float | The id of the Ethereum network (optional) (default to 1)
page = 3 # float | The number of the page to request in the collection. (optional) (default to 1)
per_page = 10 # float | The number of records to return per page. (optional) (default to 100)

    api_response = api_instance.get_asset_pairs(asset_data_a=asset_data_a, asset_data_b=asset_data_b, network_id=network_id, page=page, per_page=per_page)
except ApiException as e:
    print("Exception when calling DefaultApi->get_asset_pairs: %s\n" % e)


We welcome improvements and fixes from the wider community! To report bugs within this package, please create an issue in this repository.

Please read our contribution guidelines before getting started.

Install Code and Dependencies

Ensure that you have installed Python >=3.6, Docker, and docker-compose. Then:

pip install -e .[dev]


Tests depend on a running instance of 0x-launch-kit-backend, backed by a Ganache node with the 0x contracts deployed in it. For convenience, a docker-compose file is provided that creates this environment. And a shortcut is provided to interface with that file: ./ start_test_relayer will start those services. With them running, the tests can be run with ./ test. When you're done with testing, you can ./ stop_test_relayer.


./ clean --all


./ lint

Build Documentation

./ build_sphinx


See ./ --help-commands for more info.

Documentation for API Endpoints

All URIs are relative to http://localhost

Class Method HTTP request Description
DefaultApi get_asset_pairs GET /v2/asset_pairs
DefaultApi get_fee_recipients GET /v2/fee_recipients
DefaultApi get_order GET /v2/order/{orderHash}
DefaultApi get_order_config POST /v2/order_config
DefaultApi get_orderbook GET /v2/orderbook
DefaultApi get_orders GET /v2/orders
DefaultApi post_order POST /v2/order

Documentation For Models

Documentation For Authorization

All endpoints do not require authorization.

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