Cline Custom API Key Setup
Connect Cline to an OpenAI-compatible API in four fields, verify it, and diagnose failures by layer.
Cline is the coding client. The API provider supplies the model, authenticates the request, and bills the tokens. A custom API key connects those two layers; it does not make model usage free and it does not bypass a provider's access rules.
Cline's official OpenAI Compatible setup exposes the fields needed for this connection: API Provider, Base URL, API Key, and Model ID. With OmniaKey, one key can reach supported Claude, GPT, Gemini, DeepSeek, and other models through that interface.
Checked August 11, 2026. Cline's official documentation names the OpenAI Compatible provider and its Base URL, API Key, Model ID, and Verify flow. Model availability and prices can change, so copy current IDs from the OmniaKey model catalog.
Cline custom API key settings
Open Cline in VS Code, select the settings icon, then enter:
| Field | Value |
|---|---|
| API Provider | OpenAI Compatible |
| Base URL | https://api.omniakey.com/v1 |
| API Key | The key created in your OmniaKey dashboard |
| Model ID | An exact supported ID, such as gpt-5.6-terra |
The /v1 suffix is part of the OpenAI-compatible Base URL. Do not use the bare origin here, and do not append /chat/completions; Cline builds the request path.
Configure Cline step by step
1. Create a separate API key
Sign in to OmniaKey, fund the prepaid balance, and create an API key. A separate key for Cline makes caps, rotation, and usage review easier than sharing one credential across every tool.
Never put the literal key in source code, a repository file, an issue, or a screenshot. Paste it only into Cline's API Key field.
2. Select OpenAI Compatible
Open Cline settings and choose OpenAI Compatible under API Provider. Do not choose the official OpenAI provider when the key belongs to another provider: the provider choice determines which configuration fields and endpoint Cline uses.
3. Enter the Base URL
Use exactly:
https://api.omniakey.com/v1
Common wrong values include the bare https://api.omniakey.com, a duplicated /v1/v1, and a full /v1/chat/completions request path.
4. Enter an exact Model ID
Start with one model that is currently listed in the OmniaKey model catalog:
| Model ID | Practical starting use |
|---|---|
claude-opus-5 | Difficult repository work where deeper investigation matters |
gpt-5.6-terra | Everyday coding with a balance of capability and cost |
gemini-3.1-pro-preview | Long-context experiments that need the Gemini family |
deepseek-v4-flash | Lower-cost, fast coding and agent turns |
These examples are not aliases. Case, punctuation, and version suffixes matter. Copy the ID rather than retyping it from memory.
5. Verify before assigning a real task
Use Cline's Verify control if it is shown for the selected provider. Then run a narrow, reversible task:
Read package.json and name the package manager. Do not edit files.
A useful verification establishes four things:
- Cline accepted the custom provider settings.
- The provider accepted the API key.
- The exact model exists for that key.
- One simple model response returns without an edit or tool loop.
Only then move to a repository-changing task. The coding-agent setup overview covers the wider workflow.
How Cline BYOK billing works
BYOK means bring your own key. Cline sends requests using the provider settings you supplied, and the provider charges model usage according to that account. Cline is not turning a paid API into free usage.
Review actual input, cached input, and output tokens rather than estimating from the visible answer. Agent work includes repository context, tool calls, retries, and intermediate reasoning. The transparent billing guide explains why completed-task cost is more useful than one headline token rate.
If model choice is still open, compare the families in the coding-agent model guide before optimizing the Cline configuration.
Troubleshoot a Cline API key that is not working
Invalid API Key or HTTP 401
A 401 means the endpoint did not accept the credential supplied with the request.
Check that:
- the key came from the same provider as the Base URL;
- no leading or trailing spaces were pasted;
- the key is active and has not been rotated or deleted;
- the account has usable balance;
- Cline is still set to
OpenAI Compatible.
Creating a new model ID does not repair an authentication failure.
Model Not Found or HTTP 404
A 404 can mean the Base URL is wrong or the Model ID is unavailable. First confirm the Base URL ends once in /v1. Then copy the exact model ID from the catalog.
If the endpoint works with one listed model but not another, the connection is valid and the remaining issue is model availability or naming.
Connection error
Confirm that https://api.omniakey.com/v1 is reachable from the same machine running Cline. VPN, proxy, DNS, TLS inspection, and firewall rules can affect the IDE even when a browser page loads elsewhere.
Do not disable TLS verification to hide a certificate error. Fix the network or trust configuration instead.
The model answers but tools fail
A successful text reply proves only basic generation. Cline also depends on structured tool calls for reading, editing, and running commands. Test a read-only repository task before a large autonomous change.
If a model repeatedly produces malformed tool calls, compare a model documented for agent work rather than raising output limits blindly.
Costs are higher than expected
Long repository context can dominate the bill even when the final answer is short. Start with a narrow task, keep unrelated folders out of context, and compare cost per accepted change.
Use separate keys or caps for experiments. A cap limits financial exposure; it does not reduce the tokens an inefficient task consumes.
Security checklist
- Use a dedicated Cline key instead of a credential shared with production services.
- Set a cap appropriate for the project and task size.
- Rotate a key that appeared in a repository, terminal recording, screenshot, or issue.
- Review tool permissions before allowing shell commands or file edits.
- Start new or untrusted repositories with read-only tasks.
- Check the provider usage log after the first successful session.
The API key controls model access. Cline's file and command permissions control what the agent can do locally. Treat them as separate security boundaries.
Frequently asked questions
Can I use my own API key with Cline?
Yes. Select OpenAI Compatible, then enter the provider's Base URL, API Key, and exact Model ID. The provider must expose an API compatible with the interface Cline expects.
Is a Cline custom API key free?
No. BYOK changes who authenticates and bills the model request. The provider can still charge for input, cached input, and output tokens.
What Base URL should Cline use for OmniaKey?
Use https://api.omniakey.com/v1. Do not add /chat/completions and do not duplicate /v1.
Which model should I use in Cline?
Begin with a current model from the catalog that fits the task. gpt-5.6-terra is a balanced starting point; use stronger or cheaper models only after comparing accepted-task results.
Why does Cline say Model Not Found?
Check the exact Model ID and Base URL. A valid API Key can still lack access to a particular model, and a 404 can also come from a malformed URL.
Does Cline store my key in the repository?
Provider credentials belong in Cline's settings, not project files. Regardless of the client's storage implementation, do not copy the key into source, prompts, screenshots, or issue reports.