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Compare AI APIs & Find the Cheapest Path

Model matchups, cheaper alternatives, and setup guides — pick the right model for your workload and your budget.

Current lineup & pricing

What KissAPI charges today, per 1M tokens. Every model below runs on the same OpenAI-compatible endpoint and the same key.

ModelInputOutputvs official
Claude Opus 5$1.00$5.0080% off
Claude Sonnet 5$0.60$3.0080% off
Claude Haiku 4.5$0.20$1.0080% off
GPT-5.6 Sol$0.80$4.80—
GPT-5.6 Terra$0.48$2.88—
GPT-5.6 Luna$0.24$1.44—

Full lineup including Claude Fable 5.1, Opus 4.8 and Sonnet 4.6 on the models page, with per-model detail on pricing.

Latest models & hot topics

Every model on one key
Claude Opus 5, Sonnet 5, Fable 5.1 and the GPT-5.6 series — current specs and context limits.
Full pricing breakdown
Per-model input and output rates, with the discount against official pricing.
Claude Fable 5 API
Specs, pricing and cheaper paths for Anthropic's Fable line.
GPT-5.6 (Sol) API
Access, the Sol / Terra / Luna variants, and which one to use.
GPT-5.6 vs Claude Fable 5
The frontier model clash, and the cheaper third option.
API Cost Calculator
Plug in your token volume and compare real monthly cost.

Cheaper alternatives

Claude API Alternative
The same Anthropic models, up to 80% off official pricing.
OpenAI API Alternative
GPT and Claude on one key, no vendor lock-in.
Cheap Claude Opus API
Opus-tier reasoning without Anthropic's list price.
Cheap Claude Sonnet API
Sonnet 5 at $0.60/1M input — the best-value Claude model.

Set up your tools

Claude API for Cursor
Point Cursor at KissAPI and cut your bill up to 80%.
Claude API for Cline
Run the Cline VS Code agent for a fraction of the cost.
API for Claude Code
Route Claude Code through KissAPI with two env vars.
Claude API for Roo Code
Wire Roo Code to the real Claude models, cheaper.

Model matchups

Head-to-head breakdowns. These cover the 4.6-generation models — still useful for the reasoning-versus-cost trade-off, but check the table above for what you'll actually be billed today.

Opus 4.6 vs Sonnet 4.6
When the bigger Claude model is worth it.
Sonnet 4.6 vs Haiku 4.5
Speed and price versus reasoning.
Sonnet 4.6 vs GPT-5
Claude versus OpenAI's flagship.
Opus 4.6 vs GPT-5.5
Top-tier reasoning head to head.
GPT-5 vs GPT-5.5
Which OpenAI model fits your budget.
More guides on the blog
148 guides on APIs, coding CLIs, pricing and troubleshooting.