Show HN: OpenFreeMap – Open-Source Map Hosting

Original Article ↗ Hacker News Discussion ↗

An open-source project called OpenFreeMap aims to provide free, no-API-key map tiles as a viable alternative to commercial services like Google Maps and Mapbox, particularly for small apps and hobby projects priced out by recent cost increases. Commenters explore how it compares technically and operationally to solutions like Protomaps, PMTiles, Versatiles, and Apache Baremaps, including trade-offs in hosting, latency, file formats, and schemas. Many are enthusiastic about using or self-hosting it, while also raising sustainability concerns and suggesting clearer paid support options so the service can reliably cover server and bandwidth costs.

Use cases & demand

  • Many commenters want a free or predictable-cost alternative to Google Maps/Mapbox after painful price hikes and surprise bills.
  • Proposed uses include small business sites, neighborhood “rolodex” maps, civic hackathon projects, GPS tracking, startup apps, offline/low‑bandwidth use, and accessibility tools for visually impaired navigation.
  • Several see OpenFreeMap as a drop‑in backend replacement for existing Leaflet/MapLibre apps, or as a backup to commercial providers.

Data sources & customization

  • Property boundaries in the US are typically available via county GIS systems or tax assessor sites; commercial datasets (ReGrid, Corelogic) fill gaps.
  • House numbers and POIs exist in the tiles but often aren’t shown by default; users can expose them by editing styles (e.g., with Maputnik).
  • Some specialized maps (cycling) are hard to replicate because the OpenMapTiles schema compresses certain tags.
  • Historical basemaps are requested; people point to OpenHistoricalMap and various historical map services, but coverage and accuracy are limited.

Architecture & formats

  • OpenFreeMap distributes a Btrfs filesystem image of ~300M tiny tile files, served directly by nginx.
  • Btrfs is chosen over ext4/ZFS due to inline small-file storage and flexible inode handling; about 60% of files live in metadata, saving space and boosting performance.
  • Heavy use of hard links (e.g., ocean tiles) reduces duplication; scripts handle the ~64k hard-link limit per file.
  • Alternatives discussed:
    • MBTiles (SQLite), PMTiles (single-file archive), Versatiles, Apache Baremaps, EROFS images.
    • Planetiler + Geofabrik for generating regional mbtiles/pmtiles.
  • Benchmarks show nginx+Btrfs can saturate a 1 Gbps line; the bottleneck is bandwidth, not CPU.

PMTiles vs Btrfs debate

  • PMTiles advocates emphasize serverless/static hosting and CDN edge caching.
  • OpenFreeMap’s author reports poor latency with large (80–90 GB) PMTiles over Cloudflare range requests, especially on cold cache.
  • Others note good range performance on S3 and in genomics workloads, suggesting Cloudflare/R2 specifics may be the real problem.
  • There’s interest in head‑to‑head benchmarks (nginx+Btrfs vs pmtiles-serve vs Versatiles).

Costs, sustainability & monetization

  • Current setup: several Hetzner dedicated servers with flat‑rate bandwidth; target is roughly $175/month covered by sponsorships/donations.
  • Commenters warn about relying solely on donations and suggest: explicit business plans, paid tiers with SLAs, separate “free” and “premium” server pools, or commercial support/consulting.
  • CDN options (Fastly, Cloudflare, Bunny) are discussed; sponsorships might help, but per‑TB pricing is often far higher than Hetzner’s effective cost.