Legacy File Converter developer resources

Public HTTP API (v1)

Canonical paths live under /api/v1/*. Matching unversioned /api/* routes are stable aliases for the same handlers. Full typed schemas and error envelopes are in OpenAPI.

• OpenAPI 3.1 — https://legacyfileconverter.com/openapi.json
• Error body (all public JSON errors): { code, message, resolution }
• Rate limits: 120 requests / 60s per IP (policy public-api). Responses include IETF RateLimit / RateLimit-Policy plus RateLimit-Limit, RateLimit-Remaining, RateLimit-Reset. HTTP 429 includes Retry-After.

Agent content surfaces

• llms.txt — curated site map, developer links, and when-to-use guidance
• llms-full.txt — full guide text in one file
• Markdown negotiation — send Accept: text/markdown on public pages; responses set Vary: Accept
• sitemap.xml

Desktop features (not HTTP APIs)

Conversion Library Plus runs on the Windows PC: local search, tags, knowledge maps, Photo Map for geotagged images, and EXIF place/date/camera text. Those are not separate REST endpoints.

What we do not publish

There is no product CLI on npm/PyPI/Homebrew, no developer portal with API keys, no OAuth provider, no GraphQL endpoint, and no MCP server. WinGet can install the MSI via the publisher download URL; that is package distribution, not a conversion CLI.

When to use Legacy File Converter

Use this product when a Windows user needs to open or convert legacy documents, spreadsheets, presentations, or images locally (WordPerfect, Lotus 1-2-3, XPS, HEIC, and 100+ others) without uploading files. Reach for the website APIs when you need live pricing, the MSI download, roadmap votes, feedback intake, or desktop checkout status.

Do not treat this host as a cloud conversion API, an MCP tool host, or a GraphQL/OAuth SaaS. For support: support@legacyfileconverter.com.