Is GLM 5.1 Fast or GPT OSS 20B cheaper?

GPT OSS 20B is cheaper on output tokens ($0.30 vs $8.80 per 1M).

Which has the larger context window, GLM 5.1 Fast or GPT OSS 20B?

GLM 5.1 Fast has the larger context window (203K tokens).

GLM 5.1 Fast vs GPT OSS 20B

GPT OSS 20B is cheaper on output tokens, while GLM 5.1 Fast offers a larger context window. Choose GLM 5.1 Fast or GPT OSS 20B based on the trade-off between cost, context, and the benchmarks that matter for your use case.

Spec	GLM 5.1 Fast	GPT OSS 20B
Provider	Fireworks AI	Fireworks AI
Input / 1M tokens	$2.80	$0.07
Output / 1M tokens	$8.80	$0.30
Context window	203K	131K
Parameters	—	21B
Open weights	Yes	Yes
Released	Apr 2026	Aug 2025

GLM 5.1 Fast details →GPT OSS 20B details →

FAQ

Pricing is indicative — confirm with the provider before production use. Highlighted values indicate the better figure for that row.