You Can’t Fix Funnels with Faith You Can’t Fix Funnels with Faith Every team has one. A dashboard that "mostly works." An adoption chart that spikes when someone coughs on the tracking plan. A funnel that’s technically complete, just not accurate, recent, or reproducible. And every data engineer has been there: staring at a flatlined graph, not because the feature failed, but because a product update silently broke the cta_click event and no one noticed for three sprints. So I stopped waiting for things to break loud. I built my own behavioral analytics debugger, something that lets me trace event drift, compare payloads, and validate tracking logic before the reports start gaslighting everyone. Not because I wanted to build another tool. But because visibility was missing, and trust was fading. Why Existing Tools Didn’t Cut It Why Existing Tools Didn’t Cut It We had observability tools. Logs, metrics, dashboards. But they weren’t built for this. Our issue wasn’t pipeline failure, it was behavioral blindness. Tools like Datadog or Sentry were great at detecting system errors. But they didn’t care if your plan_selected event disappeared quietly during a frontend release. Even product analytics platforms like Amplitude or Mixpanel fell short. They’re designed to show trends, not validate payload-level consistency across schema versions. When events drifted, the charts still looked fine. We didn’t need more data. We needed alignment. Building a Debugger, Not a Dashboard Building a Debugger, Not a Dashboard The problem wasn’t the data pipeline. It was that no one, including me, could easily verify if what we were tracking was what we thought we were tracking. thought Tools existed, sure. But they focused on infra uptime, not behavioral integrity. We were shipping features with confident funnels and quietly crumbling event logs. My goal was to build something quick, internal, and brutal in its clarity: Pull raw tracking payloads for any user journey Compare schema adherence across environments Flag missing events and renamed fields Visualize event drift over time Pull raw tracking payloads for any user journey Compare schema adherence across environments Flag missing events and renamed fields Visualize event drift over time Think of it less like a dashboard, more like a cross between a diff-checker and a detective board. Designing for Drift Designing for Drift Tracking is fragile. Events change names. Fields get deprecated. Payloads mutate without warning. So I built the debugger with drift as a first-class citizen. Not something to avoid, something to catch, fast. The system pulled sample payloads from staging and production, mapped them to expected schemas, and highlighted inconsistencies with a simple red/yellow/green code. It didn’t fail when something changed, it surfaced it. I also versioned expected schemas by feature. That way, when a team changed cta_clicked to cta_tap, we could trace intent, not just break downstream dashboards. Debugging Event Data Is a Different Kind of Hard Debugging Event Data Is a Different Kind of Hard With backend systems, you get error logs, stack traces, breakpoints. When something breaks, you know. But behavioral tracking fails in silence. No alarms go off when a product team renames an event or when a frontend payload loses a field due to a conditional render. You just see conversion rates plummet, or worse, you don’t notice anything at all. Debugging event data is more like debugging assumptions. You’re not just tracing code, you’re tracing intent, naming conventions, rollout sequencing, and team communication. And unlike code, no one owns the tracking layer completely. This is what makes it so easy to miss, and so dangerous to ignore. What It’s Made Of What It’s Made Of I didn’t reinvent observability. I just reassembled it from the angles we needed most: Python scripts pulled tracking payloads via BigQuery JSON schema validator flagged field-level drift A Streamlit app visualized event timelines Slack webhooks sent alerts for payload gaps Python scripts pulled tracking payloads via BigQuery JSON schema validator flagged field-level drift A Streamlit app visualized event timelines Slack webhooks sent alerts for payload gaps No AI. No buzzwords. Just a tool that asked: what actually happened in this user journey? The Bugs It Helped Us Catch The Bugs It Helped Us Catch One feature’s adoption dropped 40% week-over-week. Product assumed churn. Marketing re-routed budget. Turns out, the frontend dev had renamed plan_select to select_plan during a component refactor. No one updated the tracking plan. The debugger flagged the new event, unmatched. Another case: Two identical looking signup_complete events, but one lacked referral_code because the logic was conditionally loaded in A/B test branches. This wasn’t a pipeline problem. It was a context problem. Yet another: an experiment launched with event tracking toggled off in the control group. No one noticed until queries returned wildly asymmetrical funnel completions. Debugger caught it by flagging abnormal event distribution across test variants. By surfacing discrepancies before they reached Looker, we stopped diagnosing symptoms and started solving causes. What I Wish Teams Knew Before They Launch What I Wish Teams Knew Before They Launch Over time, I started collecting the questions I wish we’d asked earlier. They’ve now become a checklist every time someone says “we’re launching this next sprint.” What events are being tracked, and where? Who owns the tracking schema? Is this schema version-controlled? How do we validate in staging before production? What happens if this field is null? Are we reusing events or creating new ones with the same name? What events are being tracked, and where? Who owns the tracking schema? Is this schema version-controlled? How do we validate in staging before production? What happens if this field is null? Are we reusing events or creating new ones with the same name? These aren’t blockers. They’re buffers, against chaos. And asking them has saved more cycles than any late-stage debugging ever could. buffers How to Build Your Own in Under a Day How to Build Your Own in Under a Day This doesn’t need to be complicated. Here’s how you can spin up a basic event debugger without building a SaaS: Data Source: BigQuery or Snowflake with access to raw event tables Extraction: Python or dbt scripts to sample and standardize payloads Schema Validation: Use a JSON schema validator like cerberus or pydantic Drift Detection: Diff fields by version, timestamp, or env UI: Streamlit or Retool to visualize anomalies per session or user ID Notifications: Slack webhook or email alert with flagged sessions Data Source: BigQuery or Snowflake with access to raw event tables Extraction: Python or dbt scripts to sample and standardize payloads Schema Validation: Use a JSON schema validator like cerberus or pydantic Drift Detection: Diff fields by version, timestamp, or env UI: Streamlit or Retool to visualize anomalies per session or user ID Notifications: Slack webhook or email alert with flagged sessions It’s not polished. It doesn’t need to be. You just need to see what broke before someone asks. What This Tool Helped Us Avoid Without this tool: We would’ve sunset a feature based on incomplete data We would’ve missed a refactor that removed 30% of expected funnel steps We would’ve shipped “validated” dashboards based on stale payloads We would’ve sunset a feature based on incomplete data We would’ve sunset a feature based on incomplete data We would’ve missed a refactor that removed 30% of expected funnel steps We would’ve missed a refactor that removed 30% of expected funnel steps We would’ve shipped “validated” dashboards based on stale payloads We would’ve shipped “validated” dashboards based on stale payloads More importantly, we would’ve continued eroding team trust in metrics. Fixing bugs is one thing. Avoiding second-guessing across functions? That’s another. One Bug That Changed How I Design Tracking A feature launched mid-quarter. Everything seemed fine, until we saw a drop in downstream usage. We assumed churn. We even paused development to investigate. Turns out, a minor refactor caused the key event to fire on the wrong button. Same name, different user intent. The debugger flagged it. We patched it. But we’d already lost two weeks and three roadmap items. That was the moment I added field-specific payload testing in QA. One bug created a shift: track early, validate often, and assume nothing. Debuggers Build Trust, Not Just Reports What this tool gave us wasn’t just bug fixes. It gave teams shared clarity. PMs stopped asking, "Is this real?" and started asking better questions. Analysts stopped chasing anomalies and started building confidently on validated ground. And I stopped playing dashboard detective at 11pm before a launch review. Visibility Is the New Observability Dashboards are great. But most data problems aren’t in dashboards. They’re upstream. They’re invisible. Until they’re not. If you work with event data, funnels, or behavioral metrics, build your own debugger. Not a perfect one. Just one that tells you the truth before the dashboards do. Because you can’t fix funnels with faith. But you can debug them, with intent.
