AI Models · Open-Source vs Paid

GLM 5.3 Open vs INMercury 2.5 Paid

GLM 5.3 vs Mercury 2.5 compared — price per token, context window, multimodality, openness and which to choose. Can the open-source model replace the paid one? Full 2026 breakdown.

Prices & specs refreshed from live data · olud.ai

Open-model prices = cheapest provider via OpenRouter; official maker rates may be higher.

GLM 5.3OpenZ.AI
$1.4 /M input
$4.4 /M outputNo per-token fees if you self-host
TypeOpen-weight
Context window1.3M tokens
MultimodalNo
Self-hostYes
INMercury 2.5PaidInception
$0.04 /M input
$0.15 /M outputManaged API (no infra to run)
TypeProprietary
Context window260K tokens
MultimodalNo
Self-hostNo
Choose GLM 5.3 if you want to self-host, keep your data private and skip per-token fees — it's open-weight and runs on your own hardware. Choose Mercury 2.5 if you want frontier capability through a managed API with zero infrastructure to run.

GLM 5.3 vs Mercury 2.5 specs

SpecGLM 5.3Mercury 2.5Winner
MakerZ.AIInception
TypeOpen-weightProprietaryGLM 5.3
Context window1.3M tokens260K tokensGLM 5.3
Input price$1.4/M · free self-host$0.04/MINMercury 2.5
Output price$4.4/M · free self-host$0.15/MINMercury 2.5
Vision / multimodalNoNo
Tool / function callingYesYes= Tie
Self-hostableYesNo (API only)GLM 5.3
LicenseMITProprietaryGLM 5.3

Price gap & when to choose each

29×cheaper per output token

Mercury 2.5 is ~29× cheaper than GLM 5.3 on output tokens ($0.15 vs $4.4 per M tokens).

Choose GLM 5.3 if…
  • You want to self-host or run on your cloud
  • You need the longer 1.3M context window
  • You prioritize data privacy & control
  • You are building open or reproducible AI
INChoose Mercury 2.5 if…
  • You want frontier performance through a managed API
  • You want the lower output price
  • You value reliability & ecosystem
  • You don't want to manage infrastructure

Feature comparison

CapabilityGLM 5.3Mercury 2.5
Open weights (downloadable)
Self-hostable
Runs fully offline
Vision / multimodal
Tool / function calling
1M+ context window

Benchmarks: GLM 5.3 vs Mercury 2.5

Independent benchmark scores measured by Artificial Analysis. Higher is better (except latency).

GLM 5.3
Mercury 2.5
Intelligence index
44.9
Coding index
74.8
GPQA
91.7%
Humanity's Last Exam
42.3%
Long Context Reasoning
79.7%
SciCode
59%
τ-Bench Banking
50.3%
Terminal-Bench
83.9%
Speed
54.8 tok/s
Latency
3.57s
Intelligence per $
20.9

Benchmark data by Artificial Analysis.

How GLM 5.3 and Mercury 2.5 score

🏆 Best value & openness: GLM 5.3 (4.5 vs 3.0 / 5)
CriterionGLM 5.3Mercury 2.5
Cost-efficiency4.05.0
Context window5.04.0
Openness5.01.5
Self-hosting5.01.0
Multimodality3.53.5

Scores come from live data — output price (cost), context length, open vs closed weights (openness & self-hosting) and vision/tool support (multimodality). Raw task quality isn't scored here; it depends on your benchmark — see the verdict.

What each model is

GLM 5.3 Open

Z.AI · Open-weight

GLM-5.3 is a large-scale reasoning model from Z.ai, built for complex software engineering and long-horizon agent tasks. It supports text input and output with a 1M-token context window, and improves...

Mercury 2.5 Paid

Inception · Proprietary

Mercury 2.5 is the fastest reasoning LLM, and the latest diffusion LLM (dLLM) from Inception. Instead of generating tokens sequentially, Mercury 2.5 produces and refines multiple tokens in parallel, achieving...

Other models in these families

These variants are tracked but not compared here — one page per family keeps the comparison readable.

Other variants tracked
GLM 5.3 (batch)GLM 5.3 FlashGLM 5.3 Flash (batch)GLM 5.2 (batch)GLM 5.2GLM 5GLM 5 TurboGLM 5.1GLM 5V TurboGLM 4.7GLM 4.6GLM 4.7 FlashGLM 4.5GLM 4.5 AirGLM 4.6VGLM 4.5V

Frequently asked questions

Is GLM 5.3 as good as Mercury 2.5?

GLM 5.3 is open-weight and competitive on many tasks, but Mercury 2.5 may still lead on the hardest reasoning and agentic work. The gap keeps narrowing — benchmark both on your actual use case before deciding.

Can I run GLM 5.3 locally?

Yes. GLM 5.3 has open weights, so you can self-host it on your own GPUs or run it via a low-cost API. Mercury 2.5 is API-only and cannot be self-hosted.

GLM 5.3 vs Mercury 2.5 — which should I pick in 2026?

Choose GLM 5.3 if you want to self-host, keep your data private and skip per-token fees — it's open-weight and runs on your own hardware. Choose Mercury 2.5 if you want frontier capability through a managed API with zero infrastructure to run.

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