Claude Fable 5 vs Claude Fable 5.1

A side-by-side comparison of Claude Fable 5 and Claude Fable 5.1: input/output pricing, capabilities and available endpoints, served live from J8API. Both are reachable with the same API key.

Pricing comparison

ItemClaude Fable 5Claude Fable 5.1
Input (per 1M tokens)$10$10
Output (per 1M tokens)$50$50
Cache read explicit (per 1M tokens)$1$1
Cache write 5m (per 1M tokens)$12.5$12.5

Specifications

ItemClaude Fable 5Claude Fable 5.1
Context window1,000,0001,000,000
Max output64,00064,000

Capability comparison

ItemClaude Fable 5Claude Fable 5.1
function_callingYesYes
prompt_cachingYesYes
visionYesYes

Which should you pick

Which is cheaper, Claude Fable 5 or Claude Fable 5.1?

On input, Claude Fable 5 is cheaper ($10 vs $10 per 1M tokens). On output, Claude Fable 5 is cheaper ($50 vs $50 per 1M tokens). All prices are per million tokens in USD.

What can Claude Fable 5 do that Claude Fable 5.1 cannot?

both support function_calling, prompt_caching, vision.

Can I switch between Claude Fable 5 and Claude Fable 5.1 without changing my code?

Yes. Both are available on J8API through one API key and the same OpenAI-compatible endpoint — switching means changing the model field from "claude-fable-5" to "claude-fable-5-1", nothing else.

Both are available on J8API under one API key — switching between them means changing the model field and nothing else, so you can use each where it fits rather than picking one.

Claude Fable 5 · Claude Fable 5.1 · All models