Eight years of running DocSpring on Convox
Convox is a Heroku-like PaaS in your own AWS account. We've been running DocSpring on it since 2018.
DocSpring Blog
What we've learned building DocSpring: Ruby on Rails, PDFs, testing, infrastructure, and developer tools.
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Why Claude Code MCP servers keep asking you to sign in again
Run dozens of Claude Code sessions and they sign each other out of your MCP servers, because each OAuth refresh token works only once and the sessions race to use it. One local MCPProxy now holds the tokens for all of them. Why it happens, what we changed in our fork, and the macOS setup.
Sharing Rust builds across git worktrees with kache
My shared Cargo build directory needed an unstable Cargo feature and made every worktree wait on one lock. kache shares the same builds on stable Cargo, with less disk and faster builds, once one coverage flag was out of the way.
Shiplist: Strict verification for the files that ship in your Docker images and packages
Shiplist is a new open source CLI that fails CI until every file in your repository is in exactly one list, then checks the Docker image or package you built. We built it after a list of files to remove kept letting new ones into our Enterprise image.
Ponytail vs a good AGENTS.md: What we found on our real codebase
Ponytail makes coding agents write about half as much code. I had Claude Code benchmark it on our Rails monorepo and check it against five months of my messages. Here's what we kept, what we skipped, and the setup we've now open-sourced.
Rust and git worktrees: share one Cargo build, use 60% less disk
Every git worktree builds its own copy of the same Rust dependencies. Pointing them all at one build directory looks like the fix, until one worktree runs another worktree's code without any error.
What it takes to operate a SaaS when AI agents write all the code
AI agents are helping me build the document platform I imagined when I renamed FormAPI to DocSpring, while keeping up with emails, bugs, and support.
Going all-in on Sorbet
Sorbet sat in our Rails app for 18 months with a tenth of the code typed. Then AI agents typed the rest in four days, and we kept going.
PDF form filler SDK vs API
When a PDF library is enough to fill your forms, and when a hosted API saves you the work.
Best PDF form filling APIs (2026)
DocSpring, Anvil, PDF.co, Adobe PDF Services, and Nutrient compared for filling fillable PDFs and flat PDFs.
Try DocSpring with your own documents
Upload a PDF or a Word document, or create an HTML template, then send a test request. No credit card needed.