Log Streaming nfltr tail
nfltr tail streams the last N lines of any file through a gRPC tunnel, serving a live-updating web UI with search, pause, and auto-scroll. Think tail -f over the internet, with a searchable browser interface.
Quick Start
# Stream /var/log/syslog with password protection
nfltr tail /var/log/syslog --basic-auth admin:secret --name my-server
# Stream the last 200 lines (default: 100)
nfltr tail /var/log/nginx/access.log --lines 200
# Stream with a custom agent name
nfltr tail ~/app/logs/app.log --name app-logs --basic-auth ops:s3cretOnce running, visit the public URL shown in the terminal to see the live log viewer.
How It Works
Endpoints
| Path | Description |
|---|---|
/ | Interactive web UI with search, pause/resume, auto-scroll, and keyword highlighting |
/raw | Plain-text output — pipe to grep, jq, or any CLI tool |
/stream | Server-Sent Events (SSE) — real-time line-by-line streaming for programmatic consumption |
/health | Health check endpoint — returns 200 OK |
Web UI Preview
Mar 29 14:32:08 web-01 nginx: 192.168.1.15 - - "POST /api/login HTTP/1.1" 200 89
Mar 29 14:32:09 web-01 nginx: 192.168.1.22 - - "GET /api/dashboard HTTP/1.1" 200 4501
Mar 29 14:32:10 web-01 nginx: 10.0.0.5 - - "GET /api/health HTTP/1.1" 503 0
Mar 29 14:32:11 web-01 app: [INFO] reconnecting to database...
Mar 29 14:32:12 web-01 app: [INFO] database connection restored
Mar 29 14:32:13 web-01 nginx: 192.168.1.10 - - "GET /api/health HTTP/1.1" 200 2
Features
🔍 Search & Filter
Full-text search with keyword highlighting. Filter log lines in real time without stopping the stream.
⏸️ Pause / Resume
Pause the stream to inspect a specific section. New lines buffer and appear when you resume.
📜 Auto-Scroll
Automatically scrolls to the latest line. Scroll up to pause, click "Resume" to jump back to live.
📡 SSE Streaming
The /stream endpoint delivers lines via Server-Sent Events for programmatic consumers.
🔐 Basic Auth
Protect with --basic-auth user:pass. Always use TLS when exposing over the internet.
📄 Plain Text API
/raw returns plain text — curl friendly, pipe to grep or jq.
Use Cases
- Remote log monitoring — Watch production logs from any browser without SSH access.
- CI/CD debugging — Stream build logs from a runner to a shareable URL.
- Team collaboration — Share a live log URL with a colleague debugging the same issue.
- IoT device logs — Stream logs from Raspberry Pi or edge devices behind NAT.
- Customer support — Provide a temporary log view to help customers diagnose issues.
Flags
| Flag | Default | Description |
|---|---|---|
--lines, -n | 100 | Number of lines to read from end of file |
--basic-auth | Protect with HTTP Basic Auth (user:pass) | |
--name | Custom agent name (otherwise auto-generated) |
The file path is fixed at startup — clients cannot read arbitrary files. Without --basic-auth, the log content is publicly accessible to anyone with the URL. Log files may contain sensitive data; audit the file content before exposing it.
Remote log monitoring in one command
Stream any log file to a searchable web UI. No SSH, no VPN — just nfltr tail.