AI-Powered Living Codebase Documentation SaaS
- Date
- February 25, 2026
- Category
- Micro-SaaS / Developer Tools
- Income Potential
- $2,000–$10,000/month within 6–12 months
- Startup Cost
- ~$100–$300 (domain, hosting, Claude API credits)
- Target Audience
- Small engineering teams (2–20 devs), indie developers, open-source maintainers
The Idea
Build a SaaS product that connects to a GitHub/GitLab repository and uses AI to automatically generate and maintain living documentation — READMEs, architecture overviews, onboarding guides, API references, and "how does X work" explainers — that stay in sync as the codebase evolves.
Developers hate writing docs. New hires spend weeks lost in an unfamiliar codebase. Open-source maintainers get the same "how do I set this up?" issues over and over. This product eliminates all of that with zero manual effort from the dev team.
You are a software engineer. You feel this pain personally. You know exactly what good documentation looks like and what AI can and cannot do. That gives you a decisive edge over a non-technical founder trying to build the same thing.
The Problem You Solve
Every engineering team has the same documentation problems:
- READMEs that are outdated the day after they're written
- New developers taking 2–4 weeks to understand a codebase well enough to contribute
- No architecture docs because "we'll write those later" (they never do)
- Open-source projects with zero onboarding — contributors give up and leave
- Senior devs interrupted constantly to explain "how does the auth flow work?"
The market solution today is either "write it yourself" or "pay a technical writer." Both are painful. AI makes a third option real for the first time.
Core Features (MVP)
| Feature | What It Does |
|---|---|
| Repo Connect | OAuth with GitHub/GitLab. One click to link a repo. |
| Auto README Generator | Scans repo structure, package files, and code to produce a clean, accurate README |
| Architecture Overview | Generates a plain-English summary of how the system is structured — what each major directory/module does |
| Onboarding Guide | "Day 1 for a new developer" doc: how to set up locally, how to run tests, key concepts to understand first |
| Function/Module Explainer | Ask "what does auth/middleware.ts do?" and get a plain-English answer with context |
| Auto-Sync on Push | Webhook on new commits — AI diffs the changes and updates only the affected docs automatically |
Pricing
| Tier | Who It's For | Price |
|---|---|---|
| Solo | 1 repo, 1 user, manual sync | $19/month |
| Team | Up to 10 repos, 5 users, auto-sync on push | $79/month |
| Growth | Unlimited repos, unlimited users, priority support | $199/month |
| Open Source | 1 public repo, all features | Free forever |
The free tier for open-source projects is your marketing engine. Every open-source project using your tool is a public advertisement with a "Docs powered by [YourProduct]" badge.
Tech Stack (All in Your Wheelhouse)
- Next.js + TypeScript — frontend and API routes
- Claude API (claude-sonnet-4-6) — the core AI engine for all doc generation
- GitHub/GitLab OAuth + Webhooks API — repo integration and auto-sync trigger
- Supabase — auth, database (stores generated docs, repo metadata, user accounts)
- Vercel — hosting, scales to zero when idle
- Stripe — subscriptions and billing
- shadcn/ui — fast, clean UI without hiring a designer
You can build the entire MVP solo. No infrastructure complexity. No devops headaches. Vercel + Supabase handles all of it.
How to Build the MVP (4 Weekend Sprint)
Weekend 1: GitHub OAuth + repo ingestion. Given a repo, recursively read all files and feed them to Claude with a prompt to produce a structured README. Get this working in a simple CLI first — no UI yet.
Weekend 2: Next.js frontend. Auth (Supabase), repo connect page, display generated docs. Basic Stripe checkout for the Solo tier.
Weekend 3: Auto-sync via GitHub webhooks. When a push event fires, re-run the doc generation for changed files only. Store versioned docs in Supabase.
Weekend 4: Polish, onboarding flow, public landing page. Deploy to Vercel. Launch on Hacker News "Show HN" and Product Hunt.
How to Get Your First 100 Paying Users
-
Show HN launch. Hacker News "Show HN" posts for developer tools are the single highest-ROI launch channel. Post on a Tuesday morning. Have a live demo ready. Developers in that audience are exactly your buyer.
-
Open-source badge play. Reach out to 50 popular but under-documented open-source repos on GitHub. Offer to generate their docs for free. Ask only for a badge link. Each one becomes a referral engine.
-
Dev Twitter/X. Post a before/after: a bad README vs. what your tool generates in 30 seconds. Devs share this kind of content. One viral post can drive hundreds of signups.
-
Reddit. Post demos in r/programming, r/webdev, r/devops, r/MachineLearning. Not spam — "I built this thing, here's how it works." Devs respond well to authenticity.
-
Product Hunt. Schedule a launch 2 weeks after Show HN. By then you'll have real users and testimonials to include.
Revenue Math
| Scenario | Monthly Recurring Revenue |
|---|---|
| 20 Solo + 10 Team | $1,170/month |
| 50 Solo + 25 Team + 5 Growth | $3,895/month |
| 100 Solo + 50 Team + 15 Growth | $8,850/month |
At 50 Team plan customers, you are at ~$4,000 MRR. That is close to many software engineers' take-home after-tax from a day job.
Why This Is a Product, Not a Service
The existing idea in this folder is an agency (trading time for money). This is different:
- You build it once and it sells to unlimited customers simultaneously
- No client calls, no scope creep, no custom work
- Revenue compounds — every new user adds MRR without adding your hours
- Can be operated entirely solo with no employees
- Acquirable — a profitable dev tools SaaS with recurring revenue is a real asset you can sell
This is the model that actually lets you quit your day job, not just replace it.
Path to Quitting Your Day Job
- Months 1–2: Build MVP over weekends. Validate that Claude can produce genuinely useful docs from real repos — test on your own projects first.
- Month 3: Launch. First 10 paying customers. Collect feedback aggressively.
- Months 4–6: Iterate on the top 3 requested features. Aim for $1,000 MRR.
- Months 6–9: Invest in SEO (developer tool keywords: "auto generate readme", "codebase documentation tool"). Paid acquisition optional if unit economics work.
- Months 9–12: $3,000–$5,000 MRR. Reduce day job hours if possible. Build a small waitlist for an annual plan to get a cash lump sum.
- Month 12–18: $6,000–$10,000 MRR. Quit.
Risks & Mitigations
| Risk | Mitigation |
|---|---|
| "GitHub Copilot / ChatGPT does this already" | They don't auto-sync on push or maintain structured onboarding guides. Feature depth and workflow integration are your moat. |
| Claude API costs eat margin | Cache generated docs aggressively. Only re-generate on actual meaningful diffs. Costs drop 80% with smart caching. |
| Users churn after one-time generation | Auto-sync on push makes this sticky — it's now live infrastructure, not a one-time tool. |
| Competition from well-funded startups | Niche down hard. Own "small teams and open source" before anyone else does. |
Why This Works for You Specifically
- You write code every day. You know what makes documentation actually useful vs. generic AI slop. You will build something you would personally pay for.
- Claude API is the core. No ML expertise needed — you are an integration engineer, which is exactly the skill this requires.
- Tiny surface area. No mobile app, no complex infra, no enterprise sales cycle. Ship fast, learn fast.
- High switching cost once live. Once a team's docs are generated and auto-syncing, they do not cancel. They forget it's even running and just enjoy having good docs.
First Action (Do This Today)
Pick one of your own repos — ideally one that has a mediocre README. Write a one-shot Claude prompt that reads the repo tree and key files and generates a significantly better README. Run it. If the output genuinely impresses you, the product is real. That experiment takes 45 minutes and costs under $1 in API credits.