Independent developer

mark matsu.

I build products with maps, public data, and AI. This site documents my work, technical decisions, and research.

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Software Development

Two GitHub Accounts, Zero Context Switching

How I run separate GitHub accounts for private development and public releases. Repos under one directory automatically commit and authenticate as the public identity — using includeIf, an SSH host alias, and insteadOf. Wrong operations fail loudly instead of succeeding quietly.

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