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Hubble serves a HTTP API on port 2281 by default.

Using the API

The API can be called from any programing language or browser by making a normal HTTP request.

View the API responses in a browser

Simply open the URL in a browser


Call the API using curl


Call the API via Javascript, using the axios library

import axios from "axios";

const fid = 2;
const server = "";

try {
    const response = await axios.get(`${server}/v1/castsByFid?fid=${fid}`);

    console.log(`API Returned HTTP status ${response.status}`);
    console.log(`First Cast's text is ${response.messages[0].data.castAddBody.text}`);
} catch (e) {
    // Handle errors

OpenAPI Spec

An OpenAPI spec is provided for the Hubble REST API. It can be viewed here.

Response encoding

Responses from the API are encoded as application/json, and can be parsed as normal JSON objects.

  1. Hashes, ETH addresses, keys etc... are all encoded as hex strings starting with 0x
  2. Signatures and other binary fields are encoded in base64
  3. Constants are encoded as their string types. For example, the hashScheme is encoded as HASH_SCHEME_BLAKE3 which is equivalent to the HASH_SCHEME_BLAKE3 = 1 from the protobuf schema.


Messages contain timestamps which are seconds since the Farcaster Epoch, which began on Jan 1, 2021 00:00:00 UTC.


Most endpoints support paging to get a large number of responses.

Pagination Query Parameters

pageSizeMaximum number of messages to return in a single responsepageSize=100
reverseReverse the sort order, returning latest messages firstreverse=1
pageTokenThe page token returned by the previous query, to fetch the next page. If this parameters is empty, fetch the first pagepageToken=AuzO1V0Dta...fStlynsGWT

The returned nextPageToken is empty if there are no more pages to return.

Pagination query parameters can be combined with other query parameters supported by the endpoint. For example, /v1/casts?fid=2&pageSize=3.


Fetch all casts by FID 2, fetching upto 3 casts per Page

# Fetch first page

# Fetch next page. The pageToken is from the previous response(`response.nextPageToken`)

Javascript Example

import axios from "axios";

const fid = 2;
const server = "";

let nextPageToken = "";
do {
    const response = await axios.get(`${server}/v1/castsByFid?fid=${fid}&pageSize=100&nextPageToken=${nextPageToken}`);
    // Process response....
    nextPageToken = response.nextPageToken;
} while (nextPageToken !== "")

Handling Errors

If there's an API error, the HTTP status code is set to 400 or 500 as appropriate. The response is a JSON object with detail, errCode and metadata fields set to identify and debug the errors.


$ curl ""
  "errCode": "bad_request.validation_failure",
  "presentable": false,
  "name": "HubError",
  "code": 3,
  "details": "fid must be an integer",
  "metadata": {
    "errcode": [


You can set a custom CORS header in the HTTP server by using the --http-cors-origin parameter when running your Hubble instance. Setting this to * will allow requests from any origin.


The HTTP API currently does not support any of the Sync APIs that are available in the gRPC vesion. When Hubs sync with each other, they will use the gRPC APIs instead of the HTTP APIs.