OpenAI is currently offering ChatGPT Plus free for 1 month (normally ₹1999/month). That means GPT-5.5 access at ₹0. Here's how to wire it into OpenCode — the open-source terminal coding agent — in under 5 minutes.
Step 1: Claim the Free Plus Month
- Go to chatgpt.com/#pricing
- The Plus card shows ₹0 for the first month (LIMITED TIME badge)
- Click "Claim free offer"
- Sign in with a real email — you'll need to attach a UPI/card, so do not use temp mail
🚨 Important: The free Plus offer may not work with personal email accounts (Gmail, Yahoo, etc.). Use your work/org email for the best chance of seeing the offer.
Prerequisites
Before installing, make sure you have the following:
| Tool | Version | Check | Download |
|---|---|---|---|
| Node.js | 18+ | node --version |
nodejs.org |
| npm | comes with Node | npm --version |
(bundled with Node.js) |
| Git | any | git --version |
git-scm.com |
✅ If you're on Windows and all three commands return a version number in PowerShell, you're good to go.
Step 2: Install OpenCode
OpenCode is an open-source AI coding agent that runs in your terminal. Think Cursor — but in your CLI, fully provider-agnostic.
Windows (npm — recommended):
npm install -g opencode-ai
macOS / Linux:
curl -fsSL https://opencode.ai/install | bash
macOS (Homebrew):
brew install anomalyco/tap/opencode
Windows alternatives (Scoop or Chocolatey):
scoop install opencode
# or
choco install opencode
💡 WSL users on Windows can use the curl command directly inside the WSL terminal.
Verify install:
opencode --version
Step 3: Launch and Connect OpenAI
Run OpenCode in your project directory:
cd your-project
opencode
You'll see the OpenCode TUI — it launches with a prompt and shows the current model in the status bar:
Now type /connect directly in the prompt and search for openai:
Select "OpenAI (ChatGPT Plus/Pro or API key)".
Step 4: Choose Auth Method — Browser Login (No API Key Needed!)
This is the key step. OpenCode gives you 3 options:
Select "ChatGPT Pro/Plus (browser)".
OpenCode will generate a link — copy it and paste it in the browser where your ChatGPT account is already logged in. Complete the sign-in flow there.
No API key required. No platform billing. Your Plus subscription is all you need.
Step 5: Restart and Select GPT-5.5
After completing browser auth, restart OpenCode:
opencode
Then type /models directly in the prompt and select GPT-5.5 · medium — the best balance of speed vs accuracy for day-to-day coding.
You'll see the status bar confirm: Build · GPT-5.5 OpenAI · medium ✅
What You Get
| Free Tier | Plus (Free Month) | |
|---|---|---|
| Model in ChatGPT | GPT-5.3 | GPT-5.5 |
| OpenCode auth | API key only | Browser login (no key!) |
| Cost | ₹0 | ₹0 for first month |
| Codex in ChatGPT | Trial only | ✅ Included |
Pro Tips
-
Use
mediumvariant for GPT-5.5 — best speed/accuracy tradeoff for most coding tasks -
Use
/reviewto review uncommitted changes, branches, or PRs directly from the TUI (tip shown in the OpenCode UI itself)
- Keep AGENTS.md lean — OpenCode reads it as context on every message; bloated files eat your token budget
Why OpenCode Instead of Just ChatGPT?
- Runs in your terminal — zero context switching
- Reads your actual codebase — not copy-pasted snippets
- Multi-file edits natively
- Provider-agnostic — swap to Gemini, Anthropic, or local models anytime
- Open source — github.com/sst/opencode
The free Plus month auto-renews at ₹1999. Cancel before renewal if you don't want to continue — your OpenCode setup keeps working with any other provider or API key.
Docs: opencode.ai/docs · Repo: github.com/sst/opencode
The free Plus month auto-renews at ₹1999. Cancel before renewal if you don't want to continue — your OpenCode setup keeps working with any other provider or API key.
⚠️ Set a calendar reminder now — go to chatgpt.com → profile → Manage subscription → cancel before the month ends. Easy to forget, hurts to miss.
Tested on OpenCode v1.14.33 · GPT-5.5 · May 2026
Drop a comment if you hit issues — happy to help debug.
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