Four terminal coding agents dominate the conversation in 2026: Claude Code, OpenAI’s Codex CLI, OpenCode, and Aider. They all do the same core job — read your repo, plan a change, edit files, run commands — and they can all run on cheap models. So the choice comes down to workflow, openness, and habits, not raw capability.
Here’s an honest comparison for Windows users, with a clear recommendation at the end. If you just want to cut costs on whatever you pick, start with use cheap AI models with Claude Code.
At a glance
The four compared
| Claude Code | Most polished; Anthropic endpoint or router for cheap models |
|---|---|
| Codex CLI | Fast (Rust); GitHub-friendly; config.toml providers |
| OpenCode | Open source; most flexible; 75+ providers |
| Aider | Git-native; commits each change; BYO key |
Claude Code
The benchmark for polish. The agent loop, plan mode, and tool handling are excellent, and it’s what most other tools are measured against. It’s not locked to Claude — set ANTHROPIC_BASE_URL to a compatible endpoint or use Claude Code Router for OpenAI-style providers.
Best when: you want the smoothest experience and don’t mind a little setup to point it at a cheaper model.
Codex CLI
OpenAI’s agent, rewritten in Rust for speed, with good GitHub and team-workflow integration. It accepts custom providers through ~/.codex/config.toml, so it runs on DeepSeek, Qwen, or Kimi once you set wire_api = "chat". See Codex CLI custom provider setup.
Best when: you want speed and GitHub integration, and you’re comfortable editing a TOML config.
OpenCode
The most-starred open-source coding agent, and the most flexible on providers — the AI SDK and Models.dev give it 75+ backends plus local models, configured in a few lines of JSON. See OpenCode custom providers.
Best when: you want a free, open tool with the widest model choice and a clean TUI.
Aider
The git-native pair programmer. Aider’s signature move is committing every change it makes, so your history is a clean, reviewable trail you can revert step by step. It’s BYO-key and model-agnostic. See use Qwen with Aider.
Best when: you want tight git discipline and safe, reviewable large refactors.
Cost: they’re closer than you’d think
All four are free to install; your bill is the model. Run any of them on DeepSeek pay-per-token and the cost is cents per session. Run them on a flat GLM Coding Plan and it’s a fixed monthly fee. The harness barely affects cost — see cheapest AI coding API in 2026.
Windows notes
On Windows, all four run, but the terminal agents assume a Linux shell and behave more predictably in WSL. If you’d rather stay native and visual, a VS Code extension like Cline is the better fit — see best cheap Claude Code alternatives. Setup guides: Codex on WSL, OpenCode on WSL, Aider on WSL.
The recommendation
- Pick Claude Code if you want the most refined experience and will set up a cheaper backend.
- Pick Codex CLI if you want speed and GitHub workflows and don’t mind TOML.
- Pick OpenCode if you want maximum openness and model choice.
- Pick Aider if you want a commit per change and bulletproof rollback.
If you’re undecided, OpenCode on DeepSeek is the safest “free tool, cheap model, works everywhere” starting point.
How to decide
- Terminal or editor? (these four are terminal)
- Do you want a commit per change? → Aider
- Widest model choice and open source? → OpenCode
- Speed + GitHub? → Codex CLI
- Most polish? → Claude Code
Wrapping up
Claude Code, Codex CLI, OpenCode, and Aider are all strong, all run on cheap models, and all work on Windows. Claude Code wins on polish, Codex on speed, OpenCode on flexibility, and Aider on git discipline. Because output quality follows the model rather than the harness, pick the one that fits how you work and pair it with an affordable backend.
Then set it up: Claude Code Router, Codex custom providers, or OpenCode custom providers.
