Model comparison
Claude Haiku 5.5 vs GPT OSS 20B (free)
Claude Haiku 5.5 (Anthropic) and GPT OSS 20B (free) (OpenAI) side by side: what each costs per million tokens through Rapid Router, how much context each takes, what each supports, and where independent benchmarks place them. Same API, same key; switching is a one-string change.
| Claude Haiku 5.5 | GPT OSS 20B (free) | |
|---|---|---|
| Input price per 1M | $0.100 | $0.030 |
| Output price per 1M | $0.500 | $0.140 |
| Context window | 1M tokens | 131K tokens |
| Max output | 128K tokens | 16K tokens |
| Input types | text, image, pdf | text |
| Capabilities | tools, JSON, vision, reasoning | tools, reasoning |
| Author | Anthropic | OpenAI |
What a month costs on each
| Workload | Claude Haiku 5.5 | GPT OSS 20B (free) |
|---|---|---|
| Chatbot month (15M in, 4M out) | $3.50 | $1.01 |
| RAG month (40M in, 3M out) | $5.50 | $1.62 |
| Coding month (60M in, 10M out) | $11.00 | $3.20 |
On a typical 75/25 input-output mix, GPT OSS 20B (free) costs less (about 71% less than Claude Haiku 5.5). Claude Haiku 5.5 takes the longer prompt at 1M tokens. Try your own numbers in the cost calculator.
Call either one
curl https://rapidrouter.ai/api/v1/chat/completions \
-H "Authorization: Bearer $RAPIDROUTER_API_KEY" \
-H "Content-Type: application/json" \
-d '{"model": "anthropic/claude-haiku-5-5", "messages": [{"role": "user", "content": "Hello"}]}'
# the other one: change the model string
-d '{"model": "openai/gpt-oss-20b:free", ...}'Common questions
Which is cheaper, Claude Haiku 5.5 or GPT OSS 20B (free)?
GPT OSS 20B (free) is cheaper on a typical mix of 75% input and 25% output tokens, by about 71%. Through Rapid Router both are billed at the provider list price per million tokens.
Which has the larger context window?
Claude Haiku 5.5, at 1M tokens. GPT OSS 20B (free) offers 131K tokens.
Can I switch between Claude Haiku 5.5 and GPT OSS 20B (free) without changing code?
Yes. Both are callable at https://rapidrouter.ai/api/v1 with the same OpenAI-compatible request; only the model string changes (anthropic/claude-haiku-5-5 or openai/gpt-oss-20b:free).
How do I pay for Claude Haiku 5.5 or GPT OSS 20B (free)?
Top up a Rapid Router balance by card in US dollars, and both models debit that balance per request.
More Claude models: Anthropic API pricing · More GPT: OpenAI API pricing