Z.ai: GLM 5.3 FlashX vs ByteDance Seed: Seed 2.1 Turbo

For a sample job of 1 million input tokens and 250,000 output tokens, GLM 5.3 FlashX costs $0.68 and Seed 2.1 Turbo costs $1.12, so GLM 5.3 FlashX is about 1.6 times cheaper for the same work.

GLM 5.3 FlashX reads up to 1,048,576 tokens at once, roughly 1,573 pages of text, against about 393 pages for Seed 2.1 Turbo.

Across the 18 tasks where they differ, GLM 5.3 FlashX scores higher on 18 (SQL Generation, Code Review, Code Completion and others).

GLM 5.3 FlashX was released in September 2026 and Seed 2.1 Turbo in August 2026.

Pick GLM 5.3 FlashX if you need lower cost, long documents or the stronger all-round task scores.

Costs use current list prices per million tokens; page counts assume about 0.75 words per token and 500 words per page.