Perplexity in a Python file: the 500-line search demo

What it does

This is a demo application that pairs a search engine backend (Bing or one of three Google options) with an LLM to produce conversational, cited search results. The whole thing ships in under 500 lines of Python, plus a TypeScript frontend. You bring API keys; it brings the wiring and a shareable, cached results page.

The interesting bit

The project is essentially a clean integration layer — search results feed the LLM, the LLM synthesizes answers with citations, and Lepton’s built-in KV store caches everything so links stay shareable. The “less than 500 lines” claim is the real flex: it’s a readable reference implementation, not a framework.

Key highlights

• Supports Bing, SearchApi, Serper, or Google’s Programmable Search Engine
• Built-in LLM and KV caching via Lepton’s platform (OpenAI-compatible)
• One-click deploy to Lepton AI, or run locally with python search_with_lepton.py
• Frontend builds with standard npm tooling; UI is described as “customizable pretty”
• Live demo at search.lepton.run

Caveats

• Requires Lepton AI account and workspace token; the README nudges you toward their platform
• “Less than 500 lines” refers to the Python backend — the TypeScript frontend is separate and uncounted
• Search API keys are on you; no free tier mentioned

Verdict

Good for developers who want to see how search+LLM plumbing works without parsing a SaaS pricing page. Skip it if you need a self-contained, provider-agnostic solution — this demo is quietly selling Lepton’s platform.