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HumanJot

AI writing platform

A writing environment where AI works inside the draft - inline rewrites, voice matching and revision history that never loses the author's intent.

  • React
  • Node.js
  • OpenAI
  • PostgreSQL
  • Redis
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The problem

Chat-window AI breaks the writing flow. Writers lose context, tone drifts, and edits are impossible to review.

Business challenge

Put generation inside the document with reviewable, revertible diffs and a consistent authorial voice.

Research

Interviewed 40 professional writers; the recurring complaint was not quality, it was loss of control.

Planning

CRDT-backed document core, AI actions modelled as suggested operations, voice profiles derived from the author's own corpus.

Architecture

  • Operational document store with full revision history
  • AI actions emitted as reviewable suggestion diffs
  • Voice profiles built from embedded samples of the author's work
  • Streaming inline generation with cancellation

Database design

PostgreSQL storing documents, operations and voice profiles, with Redis for live session state.

API flow

  1. 01Editor sends a selection plus an intent to the AI action endpoint
  2. 02Server assembles document context and the author's voice profile
  3. 03Response streams back as a suggestion, not a replacement
  4. 04Accepting a suggestion commits a reviewable operation

Implementation

  • Every AI edit is revertible from day one - non-negotiable constraint
  • Latency budget of 300ms to first token for inline actions
  • Voice profile quality gated behind a minimum sample size

Key features

  • Inline AI rewrites with reviewable diffs
  • Personal voice profiles
  • Full revision history
  • Real-time collaborative editing

Performance

  • Inline actions stream in under 300ms at p90
  • Document sync stable across 40+ concurrent editors in testing

Lessons learned

  • Control beats capability. Writers accept AI that they can undo.
  • Voice matching is a retrieval problem more than a prompting problem.

Taking on 2 new partnerships for Q4

Let's talk about what you're building

Thirty minutes, no pitch deck. Bring the problem - you'll leave with an honest read on scope, risk and the fastest credible path to launch.

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