# Web2Json

> Data retrieval from Web2 JSON APIs with JQ transformations.

> For the complete documentation index, see [llms.txt](/llms.txt). Markdown versions of documentation pages are available by appending `.md` to the page URL.

Source: https://dev.flare.network/fdc/attestation-types/web2-json

An attestation type that fetches JSON data from the given URL, applies a jq filter to transform the returned result, and finally returns the structured data as ABI encoded data.

**Supported sources:** WEB2

## Request body[​](#request-body "Direct link to Request body")

Field

Solidity type

Description

`url`

`string`

URL of the data source.

`httpMethod`

`string`

HTTP method to be used for the request. Supported methods: GET, POST, PUT, PATCH, DELETE.

`headers`

`string`

Stringified key-value pairs representing headers to be used in the request. Use `{}` if no headers are required.

`queryParams`

`string`

Stringified key-value pairs representing query parameters to be appended to the URL of the request. Use `{}` if no query parameters are required.

`body`

`string`

Stringified key-value pairs representing the body to be used in the request. Use `{}` if the body is not required.

`postProcessJq`

`string`

jq filter used to post-process the JSON response from the URL.

`abiSignature`

`string`

ABI signature of the struct used to encode the data after jq post-processing.

## Response body[​](#response-body "Direct link to Response body")

Field

Solidity type

Description

`abiEncodedData`

`bytes`

Raw binary data encoded to match the function parameters in ABI.

## Lowest Used Timestamp[​](#lowest-used-timestamp "Direct link to Lowest Used Timestamp")

For `lowestUsedTimestamp`, `0xffffffffffffffff` (264−12^{64}-1264−1 in hex) is used.

## Verification[​](#verification "Direct link to Verification")

The JSON response is queried from the provided URL source using the specified HTTP method, headers, query parameters, and body. If the query is unsuccessful (e.g., attempts to access a disallowed IP or hostname, attempts to redirect, takes longer than 1 second, returns a JSON response with more than 5000 keys or a depth greater than 10, returns a content-type other than "application/json", or does not return a valid JSON response), the request is rejected.

The provided jq filter is applied to the valid JSON response. If the jq filter exceeds 5000 characters, if jq filtering fails, or if jq filtering takes longer than 500 milliseconds, the request is rejected.

The provided ABI signature is used to encode the jq-filtered JSON data. If encoding fails, the request is rejected.

`LowestUsedTimestamp` is unlimited.

## Whitelisted URLs[​](#whitelisted-urls "Direct link to Whitelisted URLs")

Before a request to the FDC for data at an endpoint can be made, the specific URL must be whitelisted. On mainnets, this is done through government proposals (details in the [FIP.14](https://proposals.flare.network/FIP/FIP_14.html#31-process-of-adding-updating-or-removing-an-api-endpoint) proposal). On testnets whitelisting is **not required**, any endpoint can be used by selecting the `PublicWeb2` source.