TCP SYN (JA4T)

43384_2-4-8-1-3_1276_12

first seen 2026-07-01 14:42 · last seen 2026-08-24 11:32 · JSON

Distinct clients per day (last 30 days, peak 1/day)

Distinct clients are counted by IP-hash per complete UTC day — unlike observation counts this is insensitive to one chatty client, but NAT merges clients and address rotation splits them.

Decomposed attributes

TCP window43384
Option kinds2-4-8-1-3
MSS1276
Window scale12

Co-observed signals

Signals from other families seen in the same observation. A fingerprint spread thinly across many lower-layer signatures is a classic inconsistency signal.

TLS ClientHello (JA4)

fingerprintco-occurrences
t13d1516h2_8daaf6152771_d8a2da3f94cd Match?Exact match in Thumbprint's published controlled catalog captures: chromium 149.0.7827.102, chrome 149.0.7827.102, chrome 149.0.7827.156, +25 more.The fingerprint page shows the full measured match list. More on the catalog.5
t13d1713h1_ab0a1bf427ad_ecd0401ec68b Match?Exact match in Thumbprint's published controlled catalog captures: python-httpx 0.28.1.The fingerprint page shows the full measured match list. More on the catalog.2
t13d1517h2_8daaf6152771_dcad5a0539911
t13d1812h1_85036bcba153_b26ce05bbdd61
t13d3614h1_bcee18a5b459_5ae85263eb3b1
t13d1312h2_f57a46bbacb6_ab7e3b40a677 Match?Exact match in Thumbprint's published controlled catalog captures: go-net/http 1.26.6, go-net/http 1.26.8, go-net/http 1.26.7, +5 more.The fingerprint page shows the full measured match list. More on the catalog.1
t13d3713h1_5c443a9f7afe_adb3fbb29c1a1
t13d1713h1_ab0a1bf427ad_8537cf56674e Match?Exact match in Thumbprint's published controlled catalog captures: python-requests 2.34.2, python-requests 2.32.3, python-requests 2.33.1.The fingerprint page shows the full measured match list. More on the catalog.1
t13d5212h1_b262b3658495_8e6e362c5eac Match?Exact match in Thumbprint's published controlled catalog captures: node-fetch 24.19.0, node-fetch 22.23.1, node-fetch 24.21.0, +6 more.The fingerprint page shows the full measured match list. More on the catalog.1

HTTP request (JA4H)

fingerprintco-occurrences
ge20nr110000_65ce3e7a57b3_000000000000_000000000000 Match?Exact match in Thumbprint's published controlled catalog captures: chromium 151.0.7922.34, chromium 148.0.7778.96, chromium 147.0.7727.15, +12 more.The fingerprint page shows the full measured match list. More on the catalog.3
ge11nn050000_be0d0b335e46_000000000000_0000000000002
ge11nn06enus_fb4afd1f380a_000000000000_0000000000001
ge11nn050000_b223a0ebb0b5_000000000000_000000000000 Match?Exact match in Thumbprint's published controlled catalog captures: python-requests 2.34.2, python-requests 2.33.1, python-requests 2.32.3.The fingerprint page shows the full measured match list. More on the catalog.1
ge20nn04en00_47dc4768c81c_000000000000_0000000000001
ge20nn120000_1d5643f8516d_000000000000_000000000000 Match?Exact match in Thumbprint's published controlled catalog captures: chromium 151.0.7922.34, chromium 148.0.7778.96, chromium 147.0.7727.15, +12 more.The fingerprint page shows the full measured match list. More on the catalog.1
ge11nn06enus_21ea1759749c_000000000000_0000000000001
ge11nn07enus_6c5989145a61_000000000000_0000000000001
ge20nr09enus_755f4c16f575_000000000000_0000000000001
he11nn050000_be0d0b335e46_000000000000_0000000000001

HTTP/2 frames (Akamai)

fingerprintco-occurrences
1:65536;2:0;4:6291456;6:262144|15663105|1:1:0:220|m,a,s,p Match?Exact match in Thumbprint's published controlled catalog captures: chrome 150.0.7871.187, chromium 149.0.7827.102, chrome 149.0.7827.102, +59 more.The fingerprint page shows the full measured match list. More on the catalog.3
1:65536;2:0;4:6291456;6:262144|15663105|1:1:0:256|m,a,s,p Match?Exact match in Thumbprint's published controlled catalog captures: chromium 131.0.6778.33, chromium 151.0.7922.34, chrome 151.0.7922.137, +43 more.The fingerprint page shows the full measured match list. More on the catalog.2
2:0;4:4194304;5:16384;6:10485760|1073741824|0|a,m,p,s Match?Exact match in Thumbprint's published controlled catalog captures: go-net/http 1.26.6, go-net/http 1.26.8, go-net/http 1.26.7, +6 more.The fingerprint page shows the full measured match list. More on the catalog.1
1:65536;2:0;4:6291456;6:262144|15663105|3:1:0:220|m,a,s,p Match?Exact match in Thumbprint's published controlled catalog captures: chromium 151.0.7922.34, chromium 147.0.7727.15, chromium 145.0.7632.6, +21 more.The fingerprint page shows the full measured match list. More on the catalog.1

TCP SYN (p0f)

fingerprintco-occurrences
4:57+7:0:1276:mss*34,12:mss,sok,ts,nop,ws:df,id+:06
4:50+14:0:1276:mss*34,12:mss,sok,ts,nop,ws:df,id+:02
4:51+13:0:1276:mss*34,12:mss,sok,ts,nop,ws:df,id+:02
4:55+9:0:1276:mss*34,12:mss,sok,ts,nop,ws:df,id+:01
4:47+17:0:1276:mss*34,12:mss,sok,ts,nop,ws:df,id+:01
4:52+12:0:1276:mss*34,12:mss,sok,ts,nop,ws:df,id+:01
4:49+15:0:1276:mss*34,12:mss,sok,ts,nop,ws:df,id+:01

User-Agent

fingerprintco-occurrences
Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) HeadlessChrome/139.0.7258.5 Safari/537.364
Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0.0.0 Safari/537.361
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.361
Mozilla/5.0 (compatible; offlinerss/1.0; +https://github.com/cadamsdotcom/offlinerss)1
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0 Safari/537.361
product-scout-bot/1.01
Mozilla/5.0 (compatible; SvelteKit-FYI/1.0; +https://sveltekit.fyi)1
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0 Safari/537.361
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/151.0.0.0 Safari/537.361
FirmableBot/1.0 (+domain-check)1

Country

fingerprintco-occurrences
SG · Singapore7
US · United States6
NL · Netherlands1

Network (ASN)

fingerprintco-occurrences
AS396982 · Google LLC6
AS400940 · Railway6
AS16509 · Amazon.com, Inc.1
AS14618 · Amazon.com, Inc.1

Cross-transport links

TLS ClientHello fingerprints observed from the same client via the beacon's correlation id on the other transport (e.g. this stack over TCP ↔ that stack over QUIC).

fingerprintlinked observations
q13d0311h3_55b375c5d22e_653d80c3fe9d3
q13d0312h3_55b375c5d22e_178839b6cec11