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just 4o...

We designed just4o.chat to keep the companion honest: choose the model, stretch context without losing warmth, and understand cost before you commit.

Your control panel

Open the drawer in any chat to swap models, review memory context, monitor usage, and spin up a new project state. Every adjustment is logged so you can track how your assistant evolves.

Model palettegpt-4o · gpt-4o-mini · imagery
Context guardrailsSignals at 80% · GPT-5-nano summaries
Pricing clarityLive limits · OpenAI rate card

Multiple models, single companion

Balance warmth and efficiency by pairing gpt-4o with gpt-4o-mini inside each workspace.

  • Select premium or base per turn; we respect your choice without silent switches.
  • Overflow routes to mini with a visible badge so tone shifts never surprise you.
  • Summaries land in memory the moment you steer the conversation back to premium.

Multiple 4o checkpoints

Pick the voice you need, including the May 2024 release, without breaking the flow of a conversation.

  • Switch among current 4o snapshots and the May checkpoint inside any chat.
  • Pin preferred defaults per workspace or override them mid-dialog.
  • Preview latency, warmth, and relative cost before you confirm a switch.

Unlimited chat length with graceful summarization

Long threads stay intact thanks to GPT-5-nano compressions triggered before limits.

  • Receive a gentle prompt at 80% of your tier's context capacity.
  • Tap Summarize to condense the thread under 1,000 tokens and stay in warm mode.
  • When overflow happens, we route to mini without dropping your voice or intent.

Transparent pricing, no surprises

Your max warm-context length is the only differentiator; every other capability is included.

  • Explorer offers daily base messages, imagery, and memory with nothing paywalled.
  • Paid tiers add premium quotas while keeping projects and tools standard.
  • Live usage indicators pair with the OpenAI rate card so you always know the math.

Memory that grows with you

A dedicated memory tool call keeps system instructions in sync with what matters most to you.

  • Agents summarize key context and update the system prompt after meaningful exchanges.
  • Review, revise, or delete memories at any time; nothing is locked away.
  • See what the model will remember before every message is sent.

Global and project-based spaces

Organize ambitions without losing the through-line of your life.

  • Start a project for a book, a journal, or a focused season of work.
  • Each project carries its own memory layer alongside your global profile.
  • Invite clarity by keeping rituals, references, and tasks scoped to one lane.

Image generation built in

Call the GPT image generation model from any chat to sketch mood boards, covers, or visual prompts.

  • Generate or edit images without leaving the conversation state.
  • Save styles and seeds to reuse across projects.
  • Balance creative output and quota with a clear usage panel.