Use the chat
Open Halfbill Chat, pick a model, understand roughly what a message costs, and decide between a Chat plan and credits.
Halfbill Chat is a web chat at chat.halfbill.uk. You sign in with your Halfbill account, pick a model, and type. Messages are paid from your credits, or from a Chat plan if you have one.
What you'll need
A Halfbill account with some credits, or a Chat plan. Nothing to install.
1. Open the chat
- Go to chat.halfbill.uk and sign in.
- Click New Chat in the left menu.
- Type your message at the bottom and press Enter. Use + to attach a file or image where the model supports it.
2. Pick a model
The model picker is the box at the top of the conversation. Click it to see the list. Auto Route lets Halfbill choose for you; you can also search by name.
Which model should I pick?
| Model family | Best for | Speed and price |
|---|---|---|
| Claude Haiku | Quick questions, summaries, rewriting text | Fastest and cheapest |
| Claude Sonnet | Everyday work: writing, analysis, coding help | Balanced; the default choice |
| Claude Fable 5.1 | The strongest Anthropic model, for the hardest tasks | Slowest and priciest |
| Claude Opus and Claude Fable 5 | Hard tasks: long reasoning, complex code, careful writing. Fable 5 is the previous Fable generation | Slower and several times pricier |
| GPT-5.5, GPT-5.6, GPT-6 | The OpenAI equivalents of the tiers above, if you prefer their style | Similar range |
Start with Sonnet. Move up to Opus, or to Fable 5.1 (model id claude-fable-5-1) when an answer is not good enough; move down to Haiku for simple, repetitive tasks. The current list and the price of each model are on halfbill.uk/models.
3. How much does a message cost?
You pay per token (roughly, per word) for what you send and what the model answers. A typical message, a paragraph of question plus a few paragraphs of answer, costs well under one cent on Sonnet and a few cents on Opus. Long conversations cost more, because everything said so far is sent again with each new message. The exact per-token prices are on halfbill.uk/models, and each request appears in your dashboard under Activity with its cost.
Chat plans vs credits
- Credits (no plan): every message is paid from your balance at the per-token price; $10 of credits buys $20 of chat at vendor prices. Good if you chat now and then. Chat keeps its own balance, separate from your dashboard organizations: top up inside the chat app (Chat credits → Add in the left menu), or switch the chat to one of your organizations to spend that organization's credits.
- Chat plan: a fixed monthly price for a monthly usage allowance in the chat. Every tier gives you thousands of messages a month. Chat Basic: $32 of chat at vendor prices for $8/mo, standard models only (no Opus, Fable, GPT-5.6 Sol, or GPT-6). Chat Plus: $70 of chat at vendor prices for $14/mo, all models. Chat Pro: $120 of chat at vendor prices for $20/mo, all models. When the allowance is used up, the chat continues from your credits.
- Fair use and exceptions: on Chat Plus and Pro, Claude Fable 5.1 is included under a weekly fair-use cap (up to 8% of the Plus allowance, 10% of the Pro allowance, per week); past the cap it is billed from your credits until the week resets. Priority models (ids ending in
-max) are never covered by a chat plan and are always billed from credits. The model picker tags both cases.
Subscribe from the Pricing page inside the chat. Prices and allowances are on halfbill.uk/pricing. Not sure which one fits you? See Credits or subscription?.
Want the technical details?
See Halfbill Chat and Chat plans in the knowledge base.
Next step
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