This register records exactly one declared alternative to p0f: JA4+, which reads ACTIVE at the last field check. p0f itself reads DEAD. Every row in the table below is judged by the same rubric, from the same sweep, on the same fields — this page ranks nothing and recommends nothing, because a register that has measured no population is in no position to.
Every row below is judged by the same rule as p0f itself, from the
same field check. Supersession is only printed where a project or its
author says so — this register does not infer that one tool replaces
another because it is newer.
Read the state column with the licence column. A permissively licensed
project that stopped shipping is not safer than a copyleft one that did
not.
What p0f does, so you know what you are replacing
Passive operating-system fingerprinting from TCP/IP stack behaviour alone — window sizes, option ordering, timing — requiring no cooperation from the client and no application-layer data at all.
A substitute has to do that job, not merely occupy the same category. The technique predates every browser-level concern in this catalogue and still works, which is the point of listing it. The code itself has not moved in years and declares no licence, so treat it as a reference rather than a dependency.
How this register decides what counts as an alternative
JA4+ is recorded as a substitute for the same job. The alternative relation is symmetric and carries no ordering at all: it says these things answer the same question, and it says nothing whatsoever about which answers it better.
Nothing on this page is a ranking, a score or a recommendation, and nothing on it is a detection-test result — no entry in this register has been run against any anti-bot system by this register. What the table gives you is four measured columns and one derived one, applied identically to every row.
How to read the comparison above
Every candidate reads ACTIVE or SEMI, so the choice here is genuinely about fit rather than about survival. Compare the release column rather than the push column: a project that pushes constantly and tags rarely asks you to depend on a branch, which is a different commitment from depending on a version.
Every entry in the table declares a licence, which is less common in this catalogue than it should be — the entries that declare none are grouped separately. Read the licence column beside the state column rather than after it: a permissively licensed project that stopped shipping is not a safer dependency than a copyleft one that did not.
Why ACTIVE: pushed_at = 2026-07-21 — 24 days, within the 90-day ACTIVE threshold.
Field
Value at this printing
pushed_at
2026-07-21
archived
false
latest_release
—
license.spdx_id
NOASSERTION
stargazers_count
2000
http_status
200
fetched_at
2026-08-14T09:12:00Z
rubric_edition
2nd, in force
Endpoint: GET https://api.github.com/repos/FoxIO-LLC/ja4
unauthenticated · 60 req/hr
A live read does not change what is printed above it. The site records that you ran it; what GitHub returned is not kept. The printed state moves only when the register is swept and a new printing is issued. raw JSON
Licence is FoxIO's own, not an OSI identifier. GitHub reports NOASSERTION and so does this register — read the file before you vendor it. — ED.
Answered from the same fields the table above prints, and from no other source.
What is the best alternative to p0f?
This register does not answer that, because it publishes no ranking and has tested no tool to rank. What it can tell you is which candidates are still shipping: JA4+. The rest of the decision is fit, licence and how much of your own stack you are prepared to change.
Are these p0f alternatives still maintained?
JA4+ reads ACTIVE. Each of those states is derived from that entry's own measured fields by the rubric in force, at the field check printed in the folio, and the clause that produced it is printed on the entry page.
Why does this list not rank the alternatives?
Because a ranking would be an opinion wearing a number's clothes. Every figure on this site is a date, a count, an SPDX identifier or an HTTP status you can re-fetch from the endpoint named beside it, and there is no honest way to compress those into an ordering without inventing weights nobody published. The rubric sets states; it does not rate them against each other.
Where does the alternatives data for p0f come from?
From declared edges in the register itself, never inferred. Each edge is stored once and reversed at build time, and every field in the table is read from the same sweep that produced the rest of the catalogue. The whole set is downloadable as CC0 JSON and CSV, including the supersedes, superseded_by and alternative_to columns.
Section 07 is the half of a fingerprint that JavaScript cannot reach, and a browser-shaped page surface over a tool-shaped handshake is a contradiction that no amount of navigator patching fixes. Donut Browser is a real browser rather than an impersonating client, which resolves that layer by not having the problem — and it adds profile-level proxy handling with a launch gate that checks the exit's geography against the profile before anything starts.