Owloops/updo: A Go-Based CLI for Uptime Monitoring

Owloops/updo: A Go-Based CLI for Uptime Monitoring

Developers running production services need reliable uptime monitoring without the overhead of heavyweight SaaS platforms. Whether you're validating API health during deployments, tracking SSL certificate expiry across multiple endpoints, or building observability into CI/CD pipelines, you need tooling that integrates cleanly with existing infrastructure. Owloops/updo is an open-source uptime monitoring CLI built in Go that provides real-time metrics, alerting, and multi-region monitoring from the command line. With nearly 1,000 GitHub stars and active maintenance as of May 2026, it targets engineers who prefer composable, scriptable tools over managed dashboards.

What is Owloops/updo?

Owloops/updo is a command-line utility for monitoring website uptime and performance metrics. Developed under the Owloops organization and released under the MIT License, the project is written primarily in Go and has accumulated 998 stars and 49 forks on GitHub. The last commit was dated May 26, 2026, indicating active maintenance.

The tool occupies a specific niche in the monitoring landscape: it is not a SaaS platform with a web interface, but rather a developer-centric CLI that outputs metrics to the terminal, structured JSON logs, or external systems like Prometheus and Grafana. This design philosophy prioritizes composability and automation over visual dashboards. Engineers can embed updo into shell scripts, CI pipelines, or cron jobs without managing API keys for external services.

Updo's relevance stems from its hybrid approach. It combines local terminal-based monitoring with optional distributed execution via AWS^{↗ Bright Coding Blog} Lambda across 13 global regions. This allows teams to validate not just whether a service responds, but whether it responds from multiple geographic vantage points. The tool also tracks SSL certificate expiry—a common operational blind spot that causes preventable outages when certificates auto-renewal fails.

Key Features

Real-time terminal monitoring. Updo provides an interactive TUI (Terminal User Interface) displaying uptime percentage, response times, and SSL certificate status. For automation scenarios, --simple mode outputs plain text and --log produces structured JSON.

Multi-target concurrency. Monitor multiple URLs simultaneously from a single command invocation or via TOML configuration files. This supports both ad-hoc checks and persistent monitoring configurations.

Multi-region AWS Lambda deployment. Remote executors deploy to 13 AWS regions including us-east-1, eu-west-1, ap-southeast-1, and others. This enables distributed monitoring without maintaining infrastructure in each location.

Prometheus and Grafana integration. Metrics export via Prometheus remote-write protocol enables long-term storage and dashboard visualization. The repository includes a Docker^{↗ Bright Coding Blog} Compose stack with pre-built dashboards.

Alert notifications. Desktop notifications and webhook integrations support Slack, Discord, and custom endpoints. Webhook URLs are auto-detected by pattern matching and formatted with appropriate rich messaging.

Flexible HTTP probing. Custom headers, POST/PUT methods, request body data, SSL verification controls, and response text assertions allow API-level monitoring beyond simple GET requests.

Multiple output modes. Interactive TUI for human operators, simple text for log aggregation, and structured JSON for programmatic processing.

Use Cases

Pre-deployment smoke testing. Before promoting a release, run updo monitor --assert-text "Healthy" https://api.staging.example.com/health to validate that critical endpoints return expected responses. The assertion capability catches cases where HTTP 200 masks application-level failures.

SSL certificate expiry monitoring. Certificate auto-renewal fails silently more often than teams admit. Updo tracks certificate expiry as a first-class metric, enabling proactive alerts before expiration causes customer-facing errors.

Multi-region API validation. For globally distributed services, deploy Lambda executors with updo aws deploy --regions all then monitor from multiple locations. This catches region-specific routing issues, CDN misconfigurations, or partial outages invisible from a single vantage point.

CI/CD pipeline health gates. Integrate --simple or --log output into deployment scripts. Fail pipelines when response times exceed thresholds or when assertions fail, preventing degraded releases from reaching production.

Lightweight production monitoring. For small teams or side projects without budget for dedicated monitoring SaaS, updo running on a single VPS with webhook alerts provides sufficient coverage without recurring costs.

Installation & Setup

Updo distributes binaries for multiple platforms. The recommended methods vary by operating system.

macOS via Homebrew:

brew install owloops/tap/updo

Linux package managers:

Debian/Ubuntu:

# Replace VERSION with actual version (e.g., 0.3.7)
curl -L -O https://github.com/Owloops/updo/releases/latest/download/updo_VERSION_linux_amd64.deb
sudo dpkg -i updo_VERSION_linux_amd64.deb

Red Hat/Fedora/CentOS:

# Replace VERSION with actual version (e.g., 0.3.7)
curl -L -O https://github.com/Owloops/updo/releases/latest/download/updo_VERSION_linux_amd64.rpm
sudo rpm -i updo_VERSION_linux_amd64.rpm

Alpine Linux:

# Replace VERSION with actual version (e.g., 0.3.7)
curl -L -O https://github.com/Owloops/updo/releases/latest/download/updo_VERSION_linux_amd64.apk
sudo apk add --allow-untrusted updo_VERSION_linux_amd64.apk

Arch Linux via AUR:

yay -S updo
# or binary package
yay -S updo-bin

Nix/NixOS:

# Run directly without installation
nix run github:Owloops/updo -- monitor https://example.com

Quick install script (cross-platform):

curl -sSL https://raw.githubusercontent.com/Owloops/updo/main/install.sh | bash

Build from source (requires Go):

git clone https://github.com/Owloops/updo.git
cd updo
go build

Or install directly:

go install github.com/Owloops/updo@latest

Docker:

docker build -t updo https://github.com/Owloops/updo.git
docker run updo monitor <website-url> [options]

After installation, verify with updo --version and generate shell completions via updo completion bash > updo_completion.bash.

Real Code Examples

Basic monitoring with custom timing:

# Monitor with 10-second refresh and 5-second request timeout
updo monitor --refresh 10 --timeout 5 https://example.com

This adjusts the default 5-second refresh interval and 10-second timeout. Use shorter timeouts for fast-fail scenarios, longer for known-slow endpoints.

Authenticated API with response assertion:

updo monitor --header "Authorization: Bearer token" --assert-text "Welcome" https://example.com

The --assert-text flag validates that the response body contains the expected string. Combined with authorization headers, this enables authenticated endpoint monitoring beyond simple availability checks.

POST request with JSON body:

updo monitor --request POST --header "Content-Type: application/json" --data '{"test":"data"}' https://api.example.com

This demonstrates updo's flexibility for API monitoring—critical for health endpoints that require specific request methods or payloads.

Structured logging with jq processing:

updo monitor --log https://example.com | jq 'select(.type=="check") | .response_time_ms'

The --log flag outputs JSON for programmatic consumption. Piping through jq extracts specific fields for custom dashboards or threshold alerting.

Multi-region monitoring with AWS Lambda:

# Deploy executors first
updo aws deploy --regions us-east-1,eu-west-1

# Monitor from deployed regions
updo monitor --regions us-east-1,eu-west-1 https://example.com

This two-step workflow enables geographic distribution. The updo aws destroy --regions all command cleans up Lambda resources when no longer needed.

Advanced Usage & Best Practices

Configuration files for complex setups. When monitoring multiple targets with divergent settings—different headers, timeouts, or webhook endpoints—use TOML configuration rather than CLI flags. CLI flags apply globally; per-target granularity requires updo monitor --config example-config.toml.

Mind the body size limit. The default 1 MiB body_size_limit caps response bodies during assertion evaluation. If --assert-text fails unexpectedly on large responses, either increase the limit globally or set body_size_limit = 0 (no cap) for specific targets in TOML configuration.

Separate metrics and error streams. With --log, direct stdout and stderr to different files: updo monitor --log https://example.com > metrics.json 2> errors.json. This simplifies downstream processing by event type.

Prometheus authentication via environment variables. Rather than exposing credentials in process lists, use UPDO_PROMETHEUS_USERNAME and UPDO_PROMETHEUS_PASSWORD environment variables. The CLI flag becomes optional when the server URL is similarly exported as UPDO_PROMETHEUS_RW_SERVER_URL.

Refresh SSO credentials proactively. For AWS Lambda operations, expired SSO sessions cause opaque errors. Run aws sso login --profile your-profile before deployment to avoid mid-operation failures.

Comparison with Alternatives

Updo suits teams prioritizing composability and cost control over managed convenience. Teams needing immediate visual dashboards without setup may prefer Uptime Kuma. Organizations with existing Prometheus expertise might layer Blackbox Exporter for metric collection while using updo for ad-hoc diagnostics.

FAQ

What license covers Owloops/updo? MIT License. Free for commercial and personal use with attribution.

Does updo require AWS for basic monitoring? No. AWS Lambda is optional for multi-region distribution. Local monitoring works without cloud credentials.

Can I monitor non-HTTP services? The README documents HTTP/HTTPS monitoring only. TCP or ICMP checks are not mentioned as supported.

How do I handle expired AWS SSO sessions? Run aws sso login --profile your-profile to refresh credentials before updo aws deploy or updo aws destroy operations.

Is there a Windows-native binary? Yes. Download updo_Windows_amd64.exe from releases or use the quick install script under PowerShell.

Can alerts target multiple channels per target? The README documents single webhook_url per target. Multiple distinct channels would require separate target entries or a relay service.

What Go version is required to build from source? The README does not specify a minimum Go version. Use the latest stable release for best compatibility.

Conclusion

Owloops/updo fills a pragmatic gap between heavyweight monitoring platforms and basic curl-based scripts. Its Go implementation delivers single-binary portability, while TOML configuration and structured JSON output enable serious automation. The AWS Lambda distribution feature distinguishes it from purely local tools, and native Prometheus integration avoids the glue-code typically required to bridge CLI utilities with observability stacks.

This tool best serves platform engineers, SREs, and developers who value composable infrastructure and prefer terminal-centric workflows. It is less suited for teams needing managed alerting history, incident collaboration features, or immediate visual dashboards without setup investment.

For installation, source code, and contribution guidelines, visit https://github.com/Owloops/updo. The repository includes complete examples for Prometheus-Grafana integration and multi-region deployment workflows.

For related coverage of developer tooling and infrastructure automation, see our [INTERNAL_LINK: open-source monitoring tools] guide.