snare

README

Snare

HTTP/HTTPS proxy CLI that intercepts, captures, and replays traffic.

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Snare is a local HTTP/HTTPS proxy you run on your machine. Point HTTP_PROXY and HTTPS_PROXY at it to capture every request and response. Inspect, save, export (JSON or HAR), and replay requests from the CLI.

Features

• HTTP and HTTPS (CONNECT) with optional MITM (HTTP/1.1 and HTTP/2)
• Every request/response saved to disk (JSON per capture)
• List, watch, diff, show, replay, import, save, export, clear, delete from the CLI
• Interactive terminal UI (snare tui) — live capture list with keyboard navigation
• Mock rules that intercept matching requests and return fixed responses
• Request interception — pause, inspect, edit, forward, or drop live requests
• Stream captures as NDJSON (snare pipe) for use with jq and shell scripts
• CI assertions on captures (snare assert) with exit codes
• Hook any shell command on every new capture (--on-capture)
• Body decompression (gzip, deflate, brotli) for readable captures
• CA generate and install for trusting the proxy on your system
• Upstream proxy chaining, host rewrite rules, and outbound header rewrite/remove

Installation

go install github.com/muxover/snare@latest

Or clone and build:

git clone https://github.com/muxover/snare.git && cd snare && go build -o snare .

Quick Start

1. Start the proxy:

snare serve

1. Set your proxy and run traffic:

export HTTP_PROXY=http://127.0.0.1:8888 HTTPS_PROXY=http://127.0.0.1:8888
curl -x http://127.0.0.1:8888 http://example.com

1. List and inspect captures:

snare list
snare show <id>
snare replay <id>

Commands

Command	Description
snare serve	Start the proxy (default port 8888; supports --upstream-proxy, --rewrite-host, --add-header, --remove-header)
snare list	List recent captures (filters: --method, --status, --url, --host, --since, --until, --body; shows duration)
snare watch	Print new captures as they arrive (--interval)
snare show [id]	Show full request/response for a capture
snare diff [id-a] [id-b]	Compare two captures
snare replay [id]	Re-send one capture by ID, or replay all URL matches with --match (optional -u URL, -H headers, -n repeat)
snare import [file.har]	Import HAR entries into the capture store
snare mock add	Add a mock rule (--url, --method, --status, --body, --content-type, --header)
snare mock from [id]	Generate a mock rule from a captured response
snare mock list	List all mock rules
snare mock remove [id]	Remove a mock rule by ID or prefix
snare mock clear	Remove all mock rules
snare intercept list	List requests currently held by the proxy
snare intercept forward [id]	Release a held request to the origin
snare intercept edit [id]	Edit a held request in $EDITOR then forward it
snare intercept drop [id]	Drop a held request (client receives 502)
snare tui	Interactive terminal UI — live capture list, inspect, replay with keyboard nav
snare pipe	Stream all captures as NDJSON; use --follow to tail new arrivals
snare assert	Assert capture conditions (--url, --method, --status, --min, --max); exits 1 on failure
snare save [id]	Save one or more captures to a JSON file (-o, --all)
snare export	Export last N captures to JSON or HAR (`-f json
snare clear	Delete all captures from the store
snare delete [id]	Delete one capture by ID or prefix
snare ca generate	Generate CA certificate if missing
snare ca install	Print instructions to install CA in system trust store

Configuration

Env / flag	Description
SNARE_STORE	Directory for capture files (default: ~/.snare/captures)
SNARE_CA	Directory for CA certs (default: ~/.snare)
--port, -p	Port (default: 8888)
--bind, -b	Bind address (default: 127.0.0.1; use 0.0.0.0 for all interfaces)
--no-mitm	Disable HTTPS MITM; CONNECT is tunneled only
--max-captures	Max captures to keep; oldest pruned (default: 1000)
--upstream-proxy	Forward outbound traffic through another proxy URL
--rewrite-host	Rewrite outbound host with from=to (repeatable)
--add-header	Add or override outbound header (Key: Value, repeatable)
--remove-header	Remove outbound header by name (repeatable)
--mock-file	Load mock rules from this file (default: SNARE_MOCKS or ~/.snare/mocks.json)
SNARE_MOCKS	Path to mock rules file
--intercept	Intercept requests matching this URL pattern (use * for all)
--intercept-timeout	How long to wait for a decision before auto-dropping (default: 5m)
SNARE_INTERCEPT	Directory for pending intercept files (default: ~/.snare/intercept)
--on-capture	Shell command to run for each new capture; capture JSON is written to its stdin

Contributing

See CONTRIBUTING.md.

License

Licensed under MIT.

Links

• Repository: https://github.com/muxover/snare
• Issues: https://github.com/muxover/snare/issues
• Changelog: CHANGELOG.md

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Made with ❤️ by Jax (@muxover)