by Reflection

Reflection: Beam 1.0 501B A23B.

text open weights datacenter 501B params 1M ctx
Cheapest input
$0.3/M
on OpenRouter
Cheapest output
$1.0/M
on OpenRouter
Smallest GPU
2× AMD MI300X
$1.00/hr
Description

About Reflection: Beam 1.0 501B A23B.

Beam 1.0 501B A23B is an open model from Reflection, a sparse mixture-of-experts design with 501B total and 23B active parameters, under Apache 2.0. It takes and returns text only and was developed mainly for English. The context window is 1M tokens, and weights come in BF16, FP8 and NVFP4. Reflection built it for agentic tool use, coding and reasoning with fewer reasoning tokens. Its knowledge cutoff is June 30, 2026.

Context window

How much it can remember.

1M tokens ≈ 786,432 English words
4K 32K 128K 1M
Capabilities

What it can do.

· Vision input
· Audio input
· Video input
· Function calling
· Tool use
· JSON mode
✓ Streaming
· Fine-tuning