Why "[platform] byok" is one of the most-searched questions in AI building
If you search replit byok, cursor byok, bolt byok, or lovable byok, you're asking one specific thing: can I point this tool's AI agent at my own API key, or my Claude Pro / ChatGPT Plus subscription, instead of paying for the platform's credits?
It's a good question, and the answer matters, because metered credits are where flat-rate platforms make their margin. Bringing your own key means your tokens bill straight to Anthropic or OpenAI at cost, with no platform cut.
But the answer is muddier than it looks, because of a trap I'll get to first. Here's where each major builder actually stands as of October 29, 2026. (Policies change, so every claim below links its source for you to re-check.)
The trap: "BYOK for your app" is not "BYOK for the builder"
Several platforms advertise "bring your own key" and mean something completely different from what you're asking.
There are two places an AI key can go:
- The builder / agent: the AI that writes your code. BYOK here means your key powers the thing you prompt.
- Your built app's runtime: if the app you're building itself calls an LLM, you store a key for that. This is just an app secret. It has nothing to do with what powers the agent.
Replit, Lovable, and v0 all let you do #2 and none of them let you do #1. So their docs and forums contain the phrase "BYOK," search engines surface it for [platform] byok, and you arrive thinking you can run the agent on your own key, when all they offer is a secrets manager for the app you ship. Keep this distinction in hand for everything below.
The scorecard
| Platform | BYOK for the agent? | What you actually get |
|---|---|---|
| Cursor | Yes | Your OpenAI / Anthropic / Google / Azure OpenAI / AWS Bedrock key powers the chat and agent models you pick |
| Replit | No | Keys only for AI inside your built app; the Agent runs on Replit credits |
| Bolt (bolt.new) | No | Bolt's own model access, metered in tokens; no key slot. The open-source bolt.diy is BYOK, but you self-host it |
| Lovable | No | Credit-metered only; your own keys go into secrets for the app you build |
| v0 | No | Credits/subscription only; the key slot is for AI in the generated app |
Cursor: yes, the real thing
Cursor is the one clear yes. In Settings > Models you can add your own keys for OpenAI, Anthropic, Google, Azure OpenAI, and AWS Bedrock; those models then appear in the model picker, and on individual plans the provider bills you directly instead of drawing on your Cursor usage. (Cursor docs) A Cursor team member confirmed in December 2025 that Agent mode works with a direct key from those providers (OpenAI keys cover standard models, not reasoning models), while routers like OpenRouter aren't supported. Three caveats worth knowing: Tab autocomplete always uses Cursor's own models, Cursor's zero-data-retention policy doesn't apply when you bring your own key, and on Teams and Enterprise plans eligible own-key requests still carry Cursor's per-token rate on top of your provider bill.
Replit: no (for the Agent)
Replit's BYOK covers AI features you build into your app. By default, Replit AI Integrations gives your app managed access to OpenAI, Anthropic, Google, Grok, and OpenRouter, billed to your Replit credits; or you supply your own key through Replit secrets and the provider bills you directly. But the Replit Agent itself, the thing that writes your code, is billed in Replit credits with effort-based pricing, and the billing docs offer no way to run it on your own key. For the "power the agent with my own key" intent, it's a no. (Replit AI Integrations · Replit AI billing)
Bolt: no for bolt.new, yes only if you self-host bolt.diy
The hosted commercial bolt.new runs its Standard and Max agents on models Bolt selects behind the scenes (plus Forge, a preview agent built on open-source models Bolt hosts), all metered in tokens by subscription. There's no key slot for the builder. There's a separate open-source project, bolt.diy, that runs on your own keys (or local models) and supports 22+ model providers, but you run it yourself. The BYOK that shows up when you search "bolt" is almost always bolt.diy, not the product most people mean. (Bolt agents · Bolt tokens · bolt.diy)
Lovable: no
All of Lovable's AI is metered through one credit balance that covers building, chatting, and hosting, and its docs describe no model choice or key option for the builder. Your own provider keys, such as an OPENAI_API_KEY, go into secrets for your app's backend: the #2 kind of BYOK, not the #1 kind. (Lovable credits and usage · Lovable secrets)
v0: no
v0's generation runs on its own models and is paid through its credit/subscription tiers. You can add a provider key as an environment variable or integration inside the app v0 generates, but not to power v0 itself. (Vercel also ships an unrelated "AI Gateway BYOK": that's an API-routing product for your own code, not the v0 builder, so don't let the shared brand confuse you.) (v0 pricing · v0 AI models · AI Gateway BYOK)
Where VibeKit sits
I build VibeKit, so take the bias as given, but the whole product is built on #1, real BYOK for the agent:
- Connect your Anthropic or OpenAI key and the coding agent runs on it directly: calls go to the provider, with no markup and no middleman. (how it works)
- Or sign in with your subscription (Claude Pro / Max, or ChatGPT Plus / Pro via Codex) and the agent runs against quota you already pay for, often at $0 extra.
- No key, no problem: a platform-credit lane exists too (transparent cost + 20%, or an always-free tier at $0 that uses a pool of free models rather than one fixed model), but it's a choice, not a wall.
Two honest limits so this doesn't read like a pitch: VibeKit's direct BYOK is Anthropic and OpenAI/Codex only today, not Perplexity and not arbitrary providers. Gemini, Grok, and DeepSeek are available, but through platform credits, not your own key. And if you want the polished single-vendor IDE experience, Cursor's BYOK is excellent at what it does. VibeKit's angle is different: a mobile-first, deploy-and-host agent platform where the key (or the subscription) is yours from the first prompt.
The takeaway
For the prompt-to-app builders (Replit, bolt.new, Lovable, v0), "[platform] byok" is mostly an unmet search: the AI is locked behind their credits, and the BYOK you find refers to keys for the app you build, not the agent building it. Cursor is the exception in the IDE category. If bringing your own key (or your own subscription) to the agent is the requirement, ask any platform that question before you commit; the answer usually shows in what they don't let you configure.
Want to bring your own key to a coding agent that also deploys and hosts? Try VibeKit free, and your provider bill stays yours. More comparisons: vs Replit · vs Cursor · vs Lovable · vs Bolt.