WhyLog — Automated Engineering Decision Log & ADR Tool

🧠 AI-powered engineering knowledge

GitHub tells you what changed.
WhyLog tells you why.

WhyLog is an engineering decision log tool that automatically captures the reasoning behind code changes directly from GitHub and GitLab pull requests. Unlike traditional ADR (Architecture Decision Record) tools that require manual documentation, WhyLog uses AI to extract decision context from PR descriptions, comments, and discussions - creating a searchable institutional memory for engineering teams. It also generates codebase briefs for new hire onboarding and provides CTOs with a dashboard to track architectural decisions over time.

whylog.app/dashboard

142

Total

118

Approved

Pending

Repos

Recent Decisions

Switch from REST to GraphQL for search endpoint

api-gatewayapprovedMar 20

Use Redis for session caching instead of DB

auth-serviceapprovedMar 19

Migrate CI from Jenkins to GitHub Actions

devopspendingMar 18

Deprecate legacy PHP endpoints by Q2

backendapprovedMar 17

Trusted by teams at

◈ ACME CORP

⬢ GLOBALTECH

✦ NIMBUS

❖ VECTOR

⌘ KINETIC

⚡

Fully automatic

Watches your PRs silently. No behavior change needed.

✅

One click approve

Review AI drafts in Slack. Approve in 2 seconds.

🔍

Ask anything

"Why do we use Redis?" Get instant answers with sources.

How it works

Zero setup. Fully automatic.

WhyLog works silently in the background — no workflow changes, no prompts to fill out.

🔍

PR is detected

WhyLog silently watches your repositories. The moment a PR is merged, our AI springs into action.

Passively monitors GitHub & GitLab.

🧠

AI drafts the why

WhyLog analyzes the diff, comments, and tickets to write a structured engineering decision record.

Infers context from your entire history.

✅

Approve in Slack

Review the draft in Slack. One click to approve, edit, or reject. Decisions become instantly searchable.

Average team review: 8 seconds.

Topical Depth

What is an Engineering Decision Log?

An engineering decision log is a central registry where teams document architectural decisions, technology choices, and trade-offs. While git logs tell you what changed, they rarely explain the human intent and constraints behind the decisions.

By using an automated log, your team retains its institutional memory. You avoid re-debating old topics and prevent critical architectural knowledge from leaving when senior engineers do.

Read our guide on Architecture Decision Records (ADRs) →

git diff -- git answers WHAT, WhyLog answers WHY

📝 git show payment_manager.py

class PaymentManager:

def process_charge(self, amount, currency):

- gateway = StripeClient(timeout=5)

+ gateway = StripeClient(timeout=30) # Increased timeout

return gateway.charge(amount, currency)

🔍 Code tells you timeout = 30. But why?

DECISION #182March 20, 2026

Why did we increase this timeout?

During checkout spikes, Stripe's custom webhook endpoints trigger Paddle migrations which cause brief timeout cascades. Standard 5s timeout caused a 4.2% failure rate on cart completions. Temporarily increased to 30s as a stopgap.

Architect:Zain Ali (Lead Architect)

Sources:PR #108, Slack channel #eng-payments

Developer Velocity

Onboard New Engineers in Days, Not Weeks

Traditional developer onboarding is plagued by context hunting. New hires spend weeks tracking down old Slack threads, reading stale Confluence wikis, or booking meetings with senior engineers just to figure out codebase reasoning.

WhyLog serves as a self-documenting engineering onboarding tool. It generates dynamic codebase briefs and provides a queryable search interface so new team members can ship their first commit with confidence.

Why new hires struggle with legacy codebases →

THE OLD WAY

3 Weeks of Friction

THE WHYLOG WAY

3 Days to First Commit

Days 1-3⚠️ Stuck

Lost in Code

Setting up local dev environment, reading outdated wikis, trying to compile code without instructions.

Days 4-7⚠️ Stuck

Slack Archeology

Hunting down old Slack threads and PR comments to figure out why the auth system is structured this way.

Days 8-14⚠️ Stuck

Meeting Blockers

Bothering senior engineers for context, scheduling meetings, and waiting for replies while blocked.

Days 15-21⚠️ Stuck

PR Rejection

Submitting first pull request only to have it rejected because it violates a design choice made 6 months ago.

Estimated Wasted Salary:~$4,800 / dev

Day 1✓ Shipping

Instant Context

Clones the repo and queries WhyLog's AI search: 'Why do we use Redis for auth caching?' Get immediate answers.

Day 2✓ Shipping

Decision Maps

Browses interactive architectural decision records linked to every active service and module.

Day 3✓ Shipping

First PR Approved

Submits pull request matching all architectural patterns. Approved on first review without friction.

Onboarding Cost:~$680 / dev

Engineering Governance

CTO Dashboard for Decision Analytics

Managing engineering knowledge across multiple distributed teams is a significant challenge. Managers need visibility into what technical paths are chosen, which decisions are still pending approval, and how technical debt is being addressed.

WhyLog provides a CTO analytics dashboard that aggregates architectural events. Track decision velocity, monitor compliance, and ensure structural consensus across all your codebases.

Learn how to document engineering decisions automatically →

whylog.app/dashboard

142

Total

118

Approved

Pending

Repos

Recent Decisions

Switch from REST to GraphQL for search endpoint

api-gatewayapprovedMar 20

Use Redis for session caching instead of DB

auth-serviceapprovedMar 19

Migrate CI from Jenkins to GitHub Actions

devopspendingMar 18

Deprecate legacy PHP endpoints by Q2

backendapprovedMar 17

FAQ

Frequently Asked Questions

Got questions? We've got answers. Learn how WhyLog captures and preserves your team's context.

What is an engineering decision log?

＋

An engineering decision log is a historical record of significant technical decisions, trade-offs, and architecture choices made during a software project's development. It provides context for future developers on why decisions were made, not just what changes were implemented.

How is WhyLog different from writing ADRs manually?

＋

Manual ADRs require developers to manually write, template, and store documents in Git or wikis, which often leads to outdated documentation or skipped records. WhyLog automates this by passively monitoring GitHub and GitLab pull requests, extracting the decision context with AI, and drafting ADRs for quick Slack approval.

Does WhyLog work with GitHub and GitLab?

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Yes, WhyLog integrates directly with GitHub and GitLab. It monitors pull requests, code reviews, and discussions, automatically extracting the context and trade-offs behind your changes.

How does WhyLog help onboard new engineers?

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WhyLog builds a queryable, AI-powered knowledge base of your codebase's architecture history. New hires can ask questions like 'Why do we use Redis for session management?' and get immediate, contextual answers with references, cutting onboarding time from weeks to days.

What is the difference between WhyLog and Confluence?

＋

Confluence is a general-purpose wiki that requires manual content updates and easily becomes stale. WhyLog is a developer-focused, automated decision log that integrates directly into your git workflow (PRs, issues), ensuring context is captured passively and stays fresh.

Pricing

Recommended Plans

Generous enough for a solo dev or small OSS project to get real value and become a fan.

Monthly

Annually2 MONTHS FREE

Starter

$0/ month

Forever free. No credit card.

✓100 decisions / month
✓3 connected repos
✓Unlimited team members
✓GitHub webhook
✓Slack approvals
✓Ask Why search
✓90-day decision history

Start capturing decisions today.

Free forever for 1 repo. No credit card. No sales call.