sardanioss/net

A fork of golang.org/x/net with HTTP/2 fingerprinting support for evading bot detection systems.

Why This Fork?

Modern anti-bot systems (Akamai, Cloudflare, PerimeterX) fingerprint HTTP/2 connections by analyzing:

• SETTINGS frame order and values
• WINDOW_UPDATE (connection flow) value
• Pseudo-header order (:method, :authority, :scheme, :path)
• Header priority in HEADERS frame
• PRIORITY frames
• HPACK dynamic table indexing behavior

The standard golang.org/x/net/http2 package doesn't allow customizing these values, making Go HTTP clients easily detectable. This fork adds full control over all HTTP/2 fingerprint vectors.

Installation

go get github.com/sardanioss/net

Features

HTTP/2 Transport Configuration

import "github.com/sardanioss/net/http2"

transport := &http2.Transport{
    // Custom SETTINGS frame (order matters!)
    Settings: map[http2.SettingID]uint32{
        http2.SettingHeaderTableSize:   65536,
        http2.SettingEnablePush:        0,
        http2.SettingInitialWindowSize: 6291456,
        http2.SettingMaxHeaderListSize: 262144,
    },
    SettingsOrder: []http2.SettingID{
        http2.SettingHeaderTableSize,
        http2.SettingEnablePush,
        http2.SettingInitialWindowSize,
        http2.SettingMaxHeaderListSize,
    },

    // Custom WINDOW_UPDATE value (Chrome uses 15663105)
    ConnectionFlow: 15663105,

    // Pseudo-header order (Chrome: m,a,s,p)
    PseudoHeaderOrder: []string{":method", ":authority", ":scheme", ":path"},

    // Header priority in HEADERS frame
    HeaderPriority: &http2.PriorityParam{
        Weight:    255,  // 256 in Chrome (0-indexed)
        Exclusive: true,
        StreamDep: 0,
    },

    // Stream priority mode
    StreamPriorityMode: http2.StreamPriorityChrome,

    // Custom User-Agent
    UserAgent: "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36",
}

HPACK Indexing Control

import "github.com/sardanioss/net/http2/hpack"

// Configure via Transport
transport := &http2.Transport{
    HPACKIndexingPolicy: hpack.IndexingChrome,
    HPACKNeverIndex:     []string{"x-request-id"},
    HPACKAlwaysIndex:    []string{"accept"},
}

Available indexing policies:

• IndexingDefault - Standard Go behavior
• IndexingChrome - Emulates Chrome's indexing decisions
• IndexingNever - Never index any headers
• IndexingAlways - Always index headers (if they fit)

Per-Request Header Ordering

Use magic keys to override header order per-request:

req.Header[http2.HeaderOrderKey] = []string{"accept", "user-agent", "accept-language"}
req.Header[http2.PHeaderOrderKey] = []string{":method", ":authority", ":scheme", ":path"}

PRIORITY Frames

Send PRIORITY frames after connection preface:

transport := &http2.Transport{
    Priorities: []http2.Priority{
        {StreamID: 3, PriorityParam: http2.PriorityParam{Weight: 200, StreamDep: 0}},
        {StreamID: 5, PriorityParam: http2.PriorityParam{Weight: 100, StreamDep: 3}},
    },
}

Chrome 133 Fingerprint

To match Chrome 133's HTTP/2 fingerprint:

transport := &http2.Transport{
    Settings: map[http2.SettingID]uint32{
        http2.SettingHeaderTableSize:   65536,
        http2.SettingEnablePush:        0,
        http2.SettingInitialWindowSize: 6291456,
        http2.SettingMaxHeaderListSize: 262144,
    },
    SettingsOrder: []http2.SettingID{
        http2.SettingHeaderTableSize,
        http2.SettingEnablePush,
        http2.SettingInitialWindowSize,
        http2.SettingMaxHeaderListSize,
    },
    ConnectionFlow:     15663105,
    PseudoHeaderOrder:  []string{":method", ":authority", ":scheme", ":path"},
    HeaderPriority:     &http2.PriorityParam{Weight: 255, Exclusive: true, StreamDep: 0},
    StreamPriorityMode: http2.StreamPriorityChrome,
    HPACKIndexingPolicy: hpack.IndexingChrome,
}

Target Akamai hash: 52d84b11737d980aef856699f885ca86

API Reference

Transport Fields

Field	Type	Description
Settings	map[SettingID]uint32	Custom HTTP/2 settings values
SettingsOrder	[]SettingID	Order to send settings in SETTINGS frame
ConnectionFlow	uint32	WINDOW_UPDATE value (default: 15663105)
PseudoHeaderOrder	[]string	Order of pseudo-headers
HeaderOrder	[]string	Order of regular headers
HeaderPriority	*PriorityParam	Priority data for HEADERS frame
Priorities	[]Priority	PRIORITY frames to send
UserAgent	string	Default User-Agent header
StreamPriorityMode	StreamPriorityMode	Stream priority calculation mode
HPACKIndexingPolicy	hpack.IndexingPolicy	HPACK dynamic table indexing
HPACKNeverIndex	[]string	Headers to never index
HPACKAlwaysIndex	[]string	Headers to always index

Stream Priority Modes

Mode	Description
StreamPriorityDefault	Standard Go behavior
StreamPriorityChrome	Chrome's priority tree (exclusive on stream 0, weight 256)
StreamPriorityFirefox	Firefox's priority tree
StreamPriorityCustom	Use custom StreamPriorityFunc

HPACK Indexing Policies

Policy	Description
IndexingDefault	Standard Go behavior (index if fits)
IndexingChrome	Emulates Chrome's indexing decisions
IndexingNever	Never index any headers
IndexingAlways	Always index headers

License

BSD 3-Clause License (same as golang.org/x/net)