Alternatives · Coding Agents
OpenAI Codex CLI alternatives (2026)
OpenAI Codex CLI: OpenAI’s answer to terminal agents — open CLI, paid models; budget the plan or the API.
Its Catch: The CLI is open source, but the models are not free: you pay through ChatGPT plan quotas or API spend.
Below: 8 free or free-tier tools from the same category (coding agents), free and open source first, then the closest match by shared tags. Each keeps its own Catch.
Free / OSS · OSS/MIT · 217k GitHub stars
VerdictMIT BYOK agent across CLI/desktop/IDE. The real catches are on /log: date stamp and compaction.
CatchTwo catches worth reading on /log: “The date stamp is a trigger channel” (auto today’s-date × open-weight LoRA as a time-release fuse) and “Compaction ate the denial” (long sessions prune hard vetoes; compaction is untrusted rewrite). Re-read those two notes before you treat OpenCode as set-and-forget.
Free / OSS · OSS/MIT · 4.2k GitHub stars
VerdictMIT Codex desktop/CLI companion. Handy for visual MCP and skills configuration; audit auth, relay endpoints, and unrestricted templates before trusting it.
CatchVs T3 Code: Codex-X is Codex-specific visual configuration plus MCP/skills, not a broad remote coding environment or an independent coding model. It handles `auth.json`, supports third-party relays, and allows unrestricted prompt templates — review where credentials go, which endpoint receives requests, and what instructions can execute before using a release. Treat relays as a trust decision, not a convenience toggle.
Free / OSS · Apache-2.0 · 7.9k GitHub stars
VerdictApache coding workspace when you want desktop+web+CLI from one OSS tree and can accept Z.ai product edges.
CatchVs Claude Code, Pi, and OpenCode: ZCode is Z.ai’s full workspace stack, not Anthropic’s product CLI, Earendil’s harness, or a pure terminal OSS agent. Bootstrap is heavy (pinned Node/pnpm, desktop/runtime assets); some OAuth/product routes still point at Z.ai services. Chinese/English docs mix — English README.en.md is the clearer entry.
Free / OSS · Apache-2.0 · 54.8k GitHub stars
VerdictApache agent-native CLI hub when the bottleneck is “the software has no agent API”; skip if you only needed browser control or a thin argv parser.
CatchVs agent-browser and aclif: this is a CLI-surface generator/hub for arbitrary apps, not a browser automation agent and not a generic CLI framework alone. Many hub CLIs assume heavy upstream installs (GIMP, Blender, GIS, DAWs); star velocity is extreme (~50k) — budget the host apps, not only the thin CLI wrapper.
Free / OSS · Apache-2.0 · 5.8k GitHub stars
VerdictThe agent harness to try when you need to see and replay what the agent actually did — treat it as nightly software for now.
CatchEarly. The latest Apache release is 0.2.0 (incubating); the npm package maka-agent ships real builds under the nightly tag while latest is still a placeholder, and the CLI README warns that commands and local data formats may change. macOS is the main platform; Windows and Linux are previews. API keys are stored in a plaintext credential-vault.json readable by your OS account, and an upgrade has already dropped older JSONL transcripts. Vs opencode or Claude Code: you are picking it for the audit log and replay, not for a bigger ecosystem. Stars have climbed fast for a five-month-old repo (about 290 a week since it opened in May 2026), so don't read the count as proof of adoption.
Free / OSS · Apache-2.0 · 107k GitHub stars
VerdictGoogle terminal agent. OSS CLI remains, but consumer quota was cut 2026-06-18; Antigravity (agy) is the consumer path. Gemini-bound by design.
CatchGemini-bound lock-in—not model-agnostic like Goose or Crush. Consumer access (free/Pro/Ultra Google login) ended 2026-06-18; enterprise and API keys still work. Don't build on the old Google-login quota path. The OSS CLI remains. Antigravity CLI is the successor, not a 1:1 swap. Preview/nightly channels move fast; pin stable for production workflows. Enterprise path pushes you toward Vertex AI and Google Cloud project setup.
Free / OSS · OSS/MIT · 27.7k GitHub stars
VerdictMIT IDE+CLI agent with MCP marketplace. Roo’s active heir, not a second OpenCode.
CatchPitch IDE+platform, not “another OpenCode.” Gateway/account is convenience; BYOK stays. Marketplace and modes are the differentiator vs plain CLI harnesses. Enterprise governance rides Anaconda — evaluate if that middle layer matters for your org.
Free / OSS · Apache-2.0 · 47.6k GitHub stars
VerdictApache-2.0 hybrid review agent. Deterministic+LLM vs Semgrep/Gitleaks and vs general coding agents; BYO LLM.
CatchVs Semgrep/Gitleaks (deterministic SAST/secrets): OCR adds an LLM agent layer for context-heavy review, not a drop-in replacement for static rules alone. Vs Claude Code/SWE-agent/OpenHands (general coding agents): OCR is a purpose-built review harness, not a full autonomous coder. BYO LLM cost — you bring the model endpoint and pay the provider; the OSS CLI itself is free.
FAQ
- What are the best free alternatives to OpenAI Codex CLI?
- OpenCode, Codex-X, ZCode, CLI-Anything, Apache Maka. All are reviewed on Stack Gems in the same category (coding agents); 8 free or open source.
- What is the catch with OpenAI Codex CLI?
- The CLI is open source, but the models are not free: you pay through ChatGPT plan quotas or API spend.
- Is there an open-source alternative to OpenAI Codex CLI?
- Yes: OpenCode (OSS/MIT), Codex-X (OSS/MIT), ZCode (Apache-2.0), CLI-Anything (Apache-2.0).