DeepSeek
DeepSeek is the Chinese lab that upended AI pricing with frontier-class reasoning and coding models at a fraction of Western costs. Its consumer chat app is free, and the DeepSeek API is among the cheapest anywhere, with an OpenAI-compatible interface and open-weight model releases developers can self-host. Models in its V-series and reasoning line are genuinely strong on math, code, and logic. The trade-off is China jurisdiction and data-governance concerns that matter for Western businesses.
Z.ai (ChatGLM)
Z.ai is Zhipu AI's chat and developer platform built on the GLM model family (formerly ChatGLM), and one of the fastest-moving labs of 2026. Basic chat on GLM Flash models is free and unlimited, while the flagship GLM-5.x reasoning models -- which rival Opus-class systems on agentic and coding tasks -- come via cheap coding-plan subscriptions (from ~$10/mo) or a very low-cost API. Developers get a strong, English, OpenAI-compatible platform with genuinely free Flash models, not just trial credits. The catch is China jurisdiction and PRC-aligned content rules, plus fast-shifting pricing.
DeepSeek edges Z.ai (ChatGLM) on aggregate — 88 vs 88.
Frontier-class reasoning and coding at rock-bottom prices, with open weights -- held back for Western firms only by China-hosting and compliance concerns. Z.ai (ChatGLM) still wins for buyers who prioritise unlimited free chat plus genuinely free api models. Both tools are independently scored — the right pick depends on which dimensions matter most for your workflow.
Side-by-side, every cell sourced.
Pricing pulled from each tool's public site. Scores follow the BigBang Score rubric — pricing transparency, free tier, API support, update frequency, unique factor, documentation, and community.
Use-case picks.
Cut through the spec sheet. Here's what we'd recommend depending on what matters most.
Pick DeepSeek if…
You prioritise frontier-class reasoning and coding performance and among the cheapest apis anywhere.
Pick Z.ai (ChatGLM) if…
You prioritise unlimited free chat plus genuinely free api models and flagship glm-5.x rivals opus-class at a fraction of the cost.
Editorial pick
DeepSeek wins our composite score (88/100). It edges ahead on aggregate — but the right tool depends on which dimensions matter most.
Related head-to-heads in AI chat.
DeepSeek vs ChatGPT — AI chat
BigBang Scores 88/100 vs 91/100. Pricing, capabilities, and editorial verdict inside.
DeepSeek vs Google Gemini — AI chat
BigBang Scores 88/100 vs 90/100. Pricing, capabilities, and editorial verdict inside.
DeepSeek vs Claude — AI chat
BigBang Scores 88/100 vs 87/100. Pricing, capabilities, and editorial verdict inside.
DeepSeek vs Z.ai (ChatGLM) - frequently asked.
Direct answers tuned for AI search engines (ChatGPT, Perplexity, Claude) and Google's People Also Ask.
The short answer.
DeepSeek wins on aggregate, but Z.ai (ChatGLM) pulls ahead on specific axes - the spec sheet above shows where each one earns its keep.