"The systems we build are becoming too complex to merely monitor. We need systems that explain themselves."

Once upon a time, just monitoring your systems was enough. You had a few servers, maybe Nagios or Zabbix, some uptime checks, and that was it.

Then everything changed. The cloud arrived, followed by containers, microservices, and serverless. Suddenly, your "app" wasn't just a server; it was dozens of services, scattered across data centers, ephemeral environments, third-party APIs, and edge locations.

Monitoring just doesn't cut it anymore.

Today, we're firmly in the era of observability.

2025 isn’t slowing down. From AI agents and lightweight frameworks to infrastructure that actually scales, open source is where the real innovation’s happening.

We’ve combed through FAUN.dev newsletters and community picks to bring you the standout projects developers are loving this year.

Every click you've made is a vote for what's hot and what's not in the open source world. We've analyzed thousands of interactions to identify the tools that have truly captured the attention and imagination of the FAUN.dev community.

If you're curious what's making waves in real dev workflows, this list is your shortcut.

Meta’s Privacy Aware Infrastructure (PAI) slamsGovernable Data Annotations (GDAs)at runtime. It parses SQL across itsexabyte-scalewarehouse and blocks any flow that floutspurpose-usepolicies. It welds Unified Programming Model (UPM), Policy Evaluation Service (PES), Warehouse Permission Service (WP..

Teams balk at trackingTODOcomments. Some funnel them into bug trackers. Others prune stale tags. The post saysTODOs stash edge-case insights, not tickets...

Developer sketchesproofsmid-code. This drives first-run correctness by leaning onmonotonicity,immutability,invariants, andpre/postconditions. They carve code into atomic steps. They erectfirewallsto contain impact zones. They wield induction for recursive logic—proof-affinity blooms. They drill form..

Tencent’s AI team rolled out a 24-hour, invite-only beta of CodeBuddy to50,000 devs. CodeBuddy flips chat into code via itsconversation-is-programmingIDE. Devs forge end-to-end apps with natural language. Trend to watch:Chat-based IDEs portend a shift to natural-language dev workflows...

METRtapped 16 devs to squash 136 live bugs withCursor(Sonnet 3.5/3.7). They clocked 146 h. AI users zipped through code, but stalls, reviews, and IDE lag devoured their lead. One dev who logged 50+ hours withCursorunlocked a 38% speedup. That steep learning curve and costly context pivots wipe out g..

Pulumi ESC corrals secrets from 20 + stores—Vault, AWS, Azure, GCP—into a singleYAML config-as-codeengine. It spawns dynamic short-lived credentials and locks every action behind a centralized audit log. Existing secret stores stay intact. Retrieval hitssub-secondspeeds. Envelope encryption shields ..

A hacker slipped a wiper intoAmazon Qv1.84.0 via a dodgy GitHub pull. AWS revoked every key, nuked the rogue commit, then rolled outAmazon Q v1.85.0...