Session Recording and Playback

Capture your terminal sessions as video-like recordings that can be replayed, shared, and embedded anywhere.

What is Session Recording?

Rexec can record your terminal sessions in real-time, capturing every command, output, and timing. Recordings are stored in standard asciinema format and can be:

Replayed in the browser
Downloaded as .cast files
Shared via public links
Embedded in documentation

Key Features

High Fidelity

Records exact terminal output with timing information for accurate playback.

Lightweight

Text-based format, not screen recording. Tiny file sizes (~10KB per minute).

Shareable

Generate public links or embed in docs/blog posts.

Searchable

Text content is searchable — find specific commands in recordings.

Starting a Recording

From the Web UI

Open any terminal session
Click the Record button (🔴) in the terminal header
Optional: Set a title for the recording
Click “Start Recording”
Terminal output is now being captured

Recording captures all terminal output, including colors, formatting, and timing information.

Automatic Recording

Enable auto-recording for terminals:

Go to Settings → Recording
Enable “Auto-record new sessions”
Choose auto-record duration limit (e.g., 2 hours)
All new terminals start recording automatically

Stopping a Recording

Click the Stop Recording button (⏹️)
Recording is saved automatically
Appears in Recordings library

Recording Limits

Tier	Max Duration	Storage	Concurrent Recordings
Free	1 hour	1GB total	1 active
Pro	4 hours	10GB total	5 active
Enterprise	Unlimited	Custom	Unlimited

Recordings that exceed duration limits are automatically stopped and saved.

Viewing Recordings

Recordings Library

Access all your recordings:

Go to Recordings in the sidebar
See list of all recordings with:
- Title
- Duration
- Date recorded
- File size
Click any recording to play

Playback Controls

Player features:

▶️ Play/Pause
⏩ Speed control (0.5x, 1x, 1.5x, 2x, 3x)
⏭️ Skip idle time (auto-skip pauses >2 seconds)
🔍 Full-text search
📋 Copy commands from transcript
⬇️ Download as .cast file

Playback Example

# Recording shows:
$ git clone https://github.com/example/repo
Cloning into 'repo'...
remote: Enumerating objects: 1234, done.
[Animation of progress bar exactly as it appeared]

$ cd repo && npm install
[Shows npm install with real-time progress]

Public Links

Share recordings with anyone:

Open recording in player
Click “Share”
Toggle “Make Public”
Copy share link: https://rexec.io/r/abc123...
Send link to anyone

Public recordings are viewable without login. Perfect for documentation and tutorials.

Embedding

Embed recordings in web pages:

<!-- Embed with asciinema-player -->
<script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/asciinema-player.min.js"></script>
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/[email protected]/dist/asciinema-player.min.css" />

<div id="recording"></div>
<script>
  AsciinemaPlayer.create(
    'https://rexec.io/r/abc123.cast',
    document.getElementById('recording'),
    {
      speed: 1.5,
      theme: 'monokai',
      autoPlay: true
    }
  );
</script>

Privacy Settings

Private (Default)
Public

Only you can view
Requires login
Not listed publicly

Think carefully before making recordings public. They may contain sensitive data like API keys or passwords.

Storage Options

Rexec supports multiple storage backends:

Database Storage (Default)

Recordings stored in PostgreSQL:

# Pros:
- Simple setup
- No external dependencies
- Works out of the box

# Cons:
- Limited by DB size
- Not optimal for >10GB

S3-Compatible Storage

Amazon S3
Cloudflare R2
MinIO (Self-Hosted)

# .env configuration
S3_BUCKET=rexec-recordings
S3_REGION=us-east-1
S3_ACCESS_KEY_ID=AKIA...
S3_SECRET_ACCESS_KEY=...

# Global CDN with zero egress fees
R2_ACCOUNT_ID=your-account-id
R2_BUCKET=rexec-recordings
R2_ACCESS_KEY_ID=...
R2_SECRET_ACCESS_KEY=...
R2_PUBLIC_URL=https://recordings.example.com

S3_ENDPOINT=http://minio:9000
S3_BUCKET=recordings
S3_ACCESS_KEY_ID=minioadmin
S3_SECRET_ACCESS_KEY=minioadmin
S3_FORCE_PATH_STYLE=true

Cloudflare R2 is recommended for high-volume deployments (zero egress fees, global CDN).

File Format

Recordings use asciinema format v2 (industry standard):

// Header
{
  "version": 2,
  "width": 120,
  "height": 30,
  "timestamp": 1703347200,
  "title": "My Recording",
  "env": {"SHELL": "/bin/bash"}
}
// Events (one per line)
[0.123, "o", "$ ls\r\n"]
[0.456, "o", "file1.txt  file2.txt\r\n"]
[2.789, "o", "$ echo hello\r\n"]
[2.890, "o", "hello\r\n"]

Format Specification

Each event line:

[<time>, <type>, <data>]

time: Seconds since recording start (float)
type: "o" (output), "i" (input), "r" (resize)
data: Terminal data (text with ANSI codes)

Compatibility

Asciinema format works with:

asciinema.org - Official hosting
asciinema-player - Web player
asciinema CLI - Command-line player
Most terminal emulators

Managing Recordings

Editing Metadata

Update recording details:

Open recording
Click Settings (⚙️)
Edit:
- Title
- Description
- Privacy (public/private)
Click Save

Downloading

Download recordings as .cast files:

# Via UI
Recordings → [Select recording] → Download

# Via API
curl -O https://rexec.io/api/recordings/{id}/stream \
  -H "Authorization: Bearer $REXEC_TOKEN"

# Rename to .cast extension
mv stream my-recording.cast

Deleting

Go to Recordings
Select recording to delete
Click Delete (🗑️)
Confirm deletion

Deleted recordings cannot be recovered, even from backups.

Advanced Features

Trimming & Editing

Edit .cast files manually to trim or modify recordings:

# Download recording
curl -o recording.cast https://rexec.io/r/abc123.cast

# Edit with text editor (JSON lines format)
vim recording.cast

# Upload edited version
curl -X POST https://rexec.io/api/recordings/upload \
  -H "Authorization: Bearer $REXEC_TOKEN" \
  -F "[email protected]"

Idle Time Compression

Speed up long pauses automatically:

# Install asciinema CLI
pip install asciinema

# Compress idle time (max 2 seconds pause)
asciinema cat recording.cast | asciinema idle-time-limit 2 > compressed.cast

Converting to GIF/Video

Convert recordings to animated GIFs or MP4:

# Using asciicast2gif
npm install -g asciicast2gif
asciicast2gif recording.cast recording.gif

# Using svg-term
npm install -g svg-term-cli
svg-term --in recording.cast --out recording.svg

Recording Collaboration Sessions

When recording a collaboration session:

All participants’ input is captured
Multi-user activity shown during playback
Cursor colors preserved in recording

Enable recording before starting collaboration for full multi-user capture.

Security & Compliance

Sensitive Data

Recordings may contain:

Passwords typed in terminal
API keys in environment variables
Confidential file contents
Private repository URLs

Best practices:

Review recordings before sharing
Edit out sensitive sections
Use secret managers, not plaintext
Keep sensitive recordings private

Data Retention

Configure automatic deletion:

# In .env
RECORDINGS_RETENTION_DAYS=90  # Auto-delete after 90 days

Audit Logging

All recording events are logged:

Recording started (user, container, timestamp)
Recording stopped (duration, size)
Recording viewed (viewer, timestamp)
Recording shared (public/private toggle)
Recording downloaded (user, timestamp)
Recording deleted (user, timestamp)

View audit logs: Settings → Audit Logs

Performance Considerations

File Sizes

Typical recording sizes:

# Text-only commands
~5-10 KB per minute

# Mixed output (logs, builds)
~50-100 KB per minute

# Heavy output (npm install, docker build)
~500 KB - 2 MB per minute

Recording Overhead

Performance impact:

CPU: Less than 1% overhead
Memory: Approximately 2MB per active recording
Network: No impact (local storage)

Recording has negligible impact on terminal responsiveness.

API Integration

Start Recording

curl -X POST https://rexec.io/api/recordings/start \
  -H "Authorization: Bearer $REXEC_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "container_id": "abc123...",
    "title": "Production deployment"
  }'

Stop Recording

curl -X POST https://rexec.io/api/recordings/stop/abc123 \
  -H "Authorization: Bearer $REXEC_TOKEN"

List Recordings

curl https://rexec.io/api/recordings \
  -H "Authorization: Bearer $REXEC_TOKEN"

See API Reference for complete documentation.

Troubleshooting

Recording not capturing output

Causes:

Terminal disconnected
Storage limit reached
Browser tab backgrounded (web-only)

Fix:

Check terminal connection
Free up storage space
Keep browser tab active during recording

Playback shows garbled text

Causes:

Terminal size mismatch
Corrupted recording file
Incompatible ANSI codes

Fix:

Adjust player terminal size
Try downloading and re-uploading
Use asciinema CLI for validation

Recording file too large

Causes:

Long running commands with verbose output
Build logs or npm install captured

Fix:

Compress idle time with asciinema idle-time-limit
Edit recording to remove noisy sections
Use tee to log to file instead of recording

Best Practices

Recording Quality

Use descriptive titles (“Deploy v1.2.3 to prod”)
Trim idle time before sharing
Review content before making public
Keep recordings under 30 minutes for better UX

Storage Management

Enable auto-deletion for old recordings
Use S3/R2 for large volumes (>10GB)
Delete test recordings regularly
Compress idle time to reduce size

Sharing

Review for secrets before sharing
Use public links sparingly
Embed in docs for tutorials
Speed up playback (1.5x-2x) for demos

Use Cases

Documentation

Record CLI tutorials and embed in docs.

Bug Reports

Show exact steps to reproduce issues.

Onboarding

Create training videos for new team members.

Demos

Record product demos and share with prospects.

Compliance

Audit trail for production changes.

Debugging

Share complex debugging sessions with team.

Collaboration

Record multi-user sessions

Cloud Terminals

Record cloud terminal sessions

BYOS Agent

Record agent terminal sessions

SSH Access

Record SSH sessions via gateway

Get Started

Core Features

Deployment

User Guides

​What is Session Recording?

​Key Features

High Fidelity

Lightweight

Shareable

Searchable

​Starting a Recording

​From the Web UI

​Automatic Recording

​Stopping a Recording

​Recording Limits

​Viewing Recordings

​Recordings Library

​Playback Controls

​Playback Example

​Sharing Recordings

​Public Links

​Embedding

​Privacy Settings

​Storage Options

​Database Storage (Default)

​S3-Compatible Storage

​File Format

​Format Specification

​Compatibility

​Managing Recordings

​Editing Metadata

​Downloading

​Deleting

​Advanced Features

​Trimming & Editing

​Idle Time Compression

​Converting to GIF/Video

​Recording Collaboration Sessions

​Security & Compliance

​Sensitive Data

​Data Retention

​Audit Logging

​Performance Considerations

​File Sizes

​Recording Overhead

​API Integration

​Start Recording

​Stop Recording

​List Recordings

​Troubleshooting

​Best Practices

Recording Quality

Storage Management

Sharing

​Use Cases

Documentation

Bug Reports

Onboarding

Demos

Compliance

Debugging

​Related Features

Collaboration

Cloud Terminals

BYOS Agent

SSH Access

Build docs developers (and LLMs) love

What is Session Recording?

Key Features

Starting a Recording

From the Web UI

Automatic Recording

Stopping a Recording

Recording Limits

Viewing Recordings

Recordings Library

Playback Controls

Playback Example

Sharing Recordings

Public Links

Embedding

Privacy Settings

Storage Options

Database Storage (Default)

S3-Compatible Storage

File Format

Format Specification

Compatibility

Managing Recordings

Editing Metadata

Downloading

Deleting

Advanced Features

Trimming & Editing

Idle Time Compression

Converting to GIF/Video

Recording Collaboration Sessions

Security & Compliance

Sensitive Data

Data Retention

Audit Logging

Performance Considerations

File Sizes

Recording Overhead

API Integration

Start Recording

Stop Recording

List Recordings

Troubleshooting

Best Practices

Use Cases

Related Features