Show HN: Pdfwithlove – PDF tools that run 100% locally (no uploads, no back end) https://ift.tt/gNjRXpU

Show HN: Pdfwithlove – PDF tools that run 100% locally (no uploads, no back end) Most PDF web tools make millions by uploading documents that never needed to leave your computer. pdfwithlove does the opposite: 1. 100% local processing 2. No uploads, no backend, no tracking Features include merge/split/edit/compress PDFs, watermarks & signatures, and image/HTML/Office → PDF conversion. https://pdfwithlove.netlify.app January 19, 2026 at 02:04AM

Show HN: I quit coding years ago. AI brought me back https://ift.tt/Uv0j3tD

Show HN: I quit coding years ago. AI brought me back Quick background: I used to code. Studied it in school, wrote some projects, but eventually convinced myself I wasn't cut out for it. Too slow, too many bugs, imposter syndrome — the usual story. So I pivoted, ended up as an investment associate at an early-stage angel fund, and haven't written real code in years. Fast forward to now. I'm a Buffett nerd — big believer in compound interest as a mental model for life. I run compound interest calculations constantly. Not because I need to, but because watching numbers grow over 30-40 years keeps me patient when markets get wild. It's basically meditation for long-term investors. The problem? Every compound interest calculator online is terrible. Ugly interfaces, ads covering half the screen, can't customize compounding frequency properly, no year-by-year breakdowns. I've tried so many. They all suck. When vibe coding started blowing up, something clicked. Maybe I could actually build the calculators I wanted? I don't have to be a "real developer" anymore — I just need to describe what I want clearly. So I tried it. Two weeks and ~$100（Opus 4.5 thinking model） in API costs later: I somehow have 60+ calculators. Started with compound interest, naturally. Then thought "well, while I'm here..." and added mortgage, loan amortization, savings goals, retirement projections. Then it spiraled — BMI calculator, timezone converter, regex tester. Oops. The AI (I'm using Claude via Windsurf) handled the grunt work beautifully. I'd describe exactly what I wanted — "compound interest calculator with monthly/quarterly/yearly options, year-by-year breakdown table, recurring contribution support" — and it delivered. With validation, nice components, even tests. What I realized: my years away from coding weren't wasted. I still understood architecture, I still knew what good UX looked like, I still had domain expertise (financial math). I just couldn't type it all out efficiently. AI filled that gap perfectly. Vibe coding didn't make me a 10x engineer. But it gave me permission to build again. Ideas I've had for years suddenly feel achievable. That's honestly the bigger win for me. Stack: Next.js, React, TailwindCSS, shadcn/ui, four languages (EN/DE/FR/JA). The AI picked most of this when I said "modern and clean." Site's live at https://calquio.com . The compound interest calculator is still my favorite page — finally exactly what I wanted. Curious if others have similar stories. Anyone else come back to building after stepping away? https://ift.tt/0oBGZhY January 18, 2026 at 09:50PM

Show HN: A self-custody medical records prototype (lessons learned) https://ift.tt/W4Ip9gj

Show HN: A self-custody medical records prototype (lessons learned) Hi HN, I built an early prototype exploring whether self-custody medical records can work in practice, using cryptographic proofs without putting sensitive health data on-chain. The problem I’m testing against is healthcare data fragmentation in Indonesia, where patient records are siloed across hospitals and often unavailable in emergencies. Blockchain is used only as an immutable audit layer; the system is designed to work even if the chain changes. Key design choices: - No medical data on-chain (hashes only, for verification and audit) - All records encrypted off-chain - Patients control access via QR-based sharing (doctors don’t touch crypto) - Blockchain treated as a verification layer, not storage Lessons learned so far: - Hospitals won’t run blockchain infrastructure - Doctors won’t manage private keys - UX matters more than cryptography - Key recovery is harder than expected - Regulation shapes architecture early This is not production-ready and doesn’t solve regulation, key recovery, or hospital interoperability yet. I’m mainly looking for critical feedback: - Where this approach is fundamentally flawed - What simpler designs I should consider instead - Healthcare practitioners’ reality checks Repo and technical details are in the README. Happy to answer questions. https://ift.tt/ClPwrI7 January 18, 2026 at 12:53AM

Show HN: Hekate – A Zero-Copy ZK Engine Overcoming the Memory Wall https://ift.tt/7a0Wlnf

Show HN: Hekate – A Zero-Copy ZK Engine Overcoming the Memory Wall Most ZK proving systems are optimized for server-grade hardware with massive RAM. When scaling to industrial-sized traces (2^20+ rows), they often hit a "Memory Wall" where allocation and data movement become a larger bottleneck than the actual computation. I have been developing Hekate, a ZK engine written in Rust that utilizes a Zero-Copy streaming model and a hybrid tiled evaluator. To test its limits, I ran a head-to-head benchmark against Binius64 on an Apple M3 Max laptop using Keccak-256. The results highlight a significant architectural divergence: At 2^15 rows: Binius64 is faster (147ms vs 202ms), but Hekate is already 10x more memory efficient (44MB vs ~400MB). At 2^20 rows: Binius64 hits 72GB of RAM usage, entering swap hell on a laptop. Hekate processes the same workload in 4.74s using just 1.4GB of RAM. At 2^24 rows (16.7M steps): Hekate finishes in 88s with a peak RAM of 21.5GB. Binius64 is unable to complete the task due to OOM/Swap on this hardware. The core difference is "Materialization vs. Streaming". While many engines materialize and copy massive polynomials in RAM during Sumcheck and PCS operations, Hekate streams them through the CPU cache in tiles. This shifts the unit economics of ZK proving from $2.00/hour high-memory cloud instances to $0.10/hour commodity hardware or local edge devices. I am looking for feedback from the community, especially those working on binary fields, GKR, and memory-constrained SNARK/STARK implementations. January 18, 2026 at 12:52AM

Show HN: A smart camera that detects eye movements during REM sleep https://ift.tt/Uo4ueHM

Show HN: A smart camera that detects eye movements during REM sleep https://ift.tt/bg93ELq January 17, 2026 at 04:45AM

Show HN: Building the ClassPass for coworking spaces, would love your thoughts https://ift.tt/3opYHlq

Show HN: Building the ClassPass for coworking spaces, would love your thoughts Growing up in a family business focused on coworking and shared spaces, I saw that many people were looking for a coworking space to use for a day. They weren't ready to jump into a long-term agreement. So I created LANS to simplify coworking. Our platform allows users to buy a day pass to a coworking space in seconds. The process is simple: book your pass, arrive at the space, give your name at the front desk, and you're in. Where we are Live in San Francisco with several coworking partners. Recently started expanding beyond the Bay. 10K paid users in San Francisco. Day passes priced between $18 and $25. What we’re seeing Users often use this service. They rotate locations during the week to fit their needs and schedules. For spaces, it’s incremental usage and new foot traffic during the workday. Outside dense city centers, onboarding new spaces tends to be faster. Many suburban areas host nice boutique coworking spaces. But, they often miss a strong online presence. Day passes quickly appeal to both operators and users. What we’re working on Expanding to more cities. Adding supply while keeping quality consistent. Learning which product decisions actually improve repeat usage. Would love feedback from HN: Does this resonate with how you work today? Have you used coworking day passes before? Would you dump your coworking membership for this? https://lans.app/ January 17, 2026 at 01:54AM

Show HN: Making Claude Code sessions link-shareable https://ift.tt/UgtedH7

Show HN: Making Claude Code sessions link-shareable Hey HN! My name is Omkar Kovvali and I've been wanting to share my CC sessions with friends / save + access them easily,so I decided to make an MCP server to do so! /share -> Get a link /import -> resume a conversation in your Claude Code All shared sessions are automatically sanitized, removing api keys, tokens, and secrets. Give it a try following the Github/npm instructions linked below - would love feedback! https://ift.tt/oiNtrsR https://ift.tt/d4xhGDT January 16, 2026 at 11:50PM