momentarr

More Drumandbytes projects

A caching, serialising proxy for FlareSolverr-compatible Cloudflare solvers. Put it in front of any of them (Byparr, FlareSolverr, or whatever comes next): repeat requests stop launching a browser, and bursts stop stacking them. It speaks the same /v1 API, so Prowlarr and friends point at momentarr instead of the solver, and nothing else changes.

At a glance

Measured 2026-09-27 on one machine, same IP, same sites (1337x.to, kickasstorrents.to, extratorrent.st), in a 2 GiB container VM:

	Without momentarr	With momentarr
Repeat request to an already-solved site	6–11 s (Byparr), 12–13 s (FlareSolverr): a full browser solve every time	~0.1 s median (max 0.22 s), plain HTTP, no browser
Several unsolved sites at once	one browser per request, all at the same time	one browser at a time; 3 of 3 succeeded, solved in turn
Memory between solves	a browser spike (~0.9–1.1 GiB) on every request	the solver idles; momentarr itself uses ~6 MiB

The cached path never reaches the solver, so the ~0.1 s holds whichever solver you run behind it.

Why

A solver spins up a browser per challenge, and browsers are what OOM a small node. Two requests at once means two browsers. Solving the same site again on every search also means the same browser spike each time, even though the cf_clearance cookie from the last solve is still valid.

momentarr does two things in front of the solver:

• Reuses the clearance. cf_clearance is bound to the client IP and user agent, not to the browser. After a solve, momentarr keeps the cookies and user agent per host. The next request for that host is a plain HTTP fetch with them, taking about 100 ms and no browser. If the site challenges anyway, the entry is dropped and the request goes to the solver.
• Runs one solve at a time. Everything that needs the solver waits for a slot (BACKEND_CONCURRENCY, default 1). After the wait it checks the cache again, so a burst of searches against one site costs a single solve.

Queue time counts against the request's maxTimeout, the same as a busy FlareSolverr. Set Prowlarr's request timeout high enough to cover a solve plus whatever is ahead of it (120 s covers about eight unsolved sites at once).

Because it only needs the FlareSolverr API, momentarr isn't tied to any solver. When a better one appears, swap BACKEND_URL and keep the cache and the queue.

When it doesn't help

Some sites bind the clearance to the solving browser's TLS fingerprint, not just its IP and user agent. A plain HTTP replay gets challenged there, so momentarr drops the cookie and solves again every time: correct, but no faster than the solver alone. You still get the queue.

It must share the solver's egress IP. In Kubernetes, run both as containers in the same pod as the consumer (e.g. behind a VPN sidecar).

Configuration

Env	Default	Meaning
PORT	8191	Listen port (FlareSolverr's)
BACKEND_URL	http://127.0.0.1:8192	The real solver
BACKEND_CONCURRENCY	1	Solver requests in flight
COOKIE_DIR	/tmp/momentarr-cookies	Clearance cache
COOKIE_TTL_HOURS	720	Upper bound; the cookie's own expiry wins if sooner. Sites set cf_clearance from 30 minutes (Cloudflare's default) up to a year (1337x); a revoked one is dropped as soon as the site challenges it
LOG_LEVEL	info	debug, info, warn or error

Logs

The output is logfmt on stderr.

• info logs one line per request, saying whether it was served from cache, solved by the backend or passed through, with timings. Every 15 minutes it adds a heartbeat line with counters (cache hits, rejected clearances, solves, failures, queue timeouts).
• warn covers sites rejecting a clearance, queue timeouts, cache I/O and unparseable backend replies.
• error means the backend is unreachable or a forward failed. Backend reachability is logged when it changes, not on every beat.
• debug traces each request step by step.

Not cached: requests with returnScreenshot, and hosts whose solve returned no cookies. sessions.* commands are passed through, through the same queue.

Run

docker run -d --name byparr -e PORT=8192 -p 8191:8191 ghcr.io/thephaseless/byparr:latest
docker run -d --name momentarr --network container:byparr ghcr.io/drumandbytes/momentarr:latest
curl -s localhost:8191/v1 -d '{"cmd":"request.get","url":"https://example.com"}'

The image is FROM scratch: a static binary, CA certificates and /tmp, running as UID 1000. It works with a read-only root filesystem as long as /tmp is writable.

How it was made

momentarr was developed with an AI coding assistant (Claude). The design, review and testing are mine, and it runs in my own homelab behind Prowlarr.