Custom Connectors
The Apps tab covers services Buildify has built a ready-made connection for. Custom connectors cover everything else — any service that offers an API.
There are two tabs for this, and they do different jobs:
- Custom API — connect to a service's API. This is the one most people want
- Custom MCP — connect to an MCP server. More technical, and less common
:::note Do you actually need this? If you don't already have an account with the service you're trying to connect, and you've never heard of an API key, you probably don't need these tabs. Start with the Apps tab instead — those connections need nothing but your normal login.
Nothing here is required to use Buildify. :::
What an API key is, in plain terms
Most online services let other software talk to them. To prove that software has your permission, the service gives you a long secret string of characters — an API key. It works like a password made specifically for apps rather than people.
You get one from the service you want to connect, not from Buildify. It's usually under a section called API, API keys, Developers, or Integrations in that service's own settings.
Two things to keep in mind:
- Treat it like a password. Anyone who has it can act on your account
- Copy it when it's first shown. Most services display a new key only once, and you'll have to create a fresh one if you lose it
Some services offer keys with different levels of access — often "read only" versus "full access". If you're offered the choice, pick the most limited one that does what you need. A read-only key means the AI can look things up but can't change or delete anything.
Custom API connectors
The easy way: a ready-made provider
Buildify includes shortcuts for a number of well-known services, so you don't have to work out any of the technical details. If the service you want is one of these, use this route.
- Click your avatar → Settings → Connectors
- Open the Custom API tab
- Find the service in the grid and click Connect
- Paste in your API key
- Click Save
That's the whole process. Buildify already knows the service's address and how it expects to be given a key.
The services with ready-made shortcuts are shown in the grid — they include OpenAI, Anthropic, Google Gemini, Stripe, PostHog, OpenRouter, Brex, Bill.com, Fly.io, AWS, and Fusen.
A few ask for one or two extra details alongside the key, because the service needs them to know which account you mean:
| Service | Also asks for | Where to find it |
|---|---|---|
| Bill.com | Org ID | Visible in the Bill.com web address when you're signed in |
| Fly.io | Organization | The org slug — run flyctl orgs list, or it's personal for a personal account |
| AWS | Access Key ID, Secret Access Key, Default Region | From your AWS security credentials. The region looks like us-east-1 |
Once saved, the service shows as Connected with the key hidden behind dots. Click Remove to disconnect it.
The manual way: any other service
If the service isn't in the grid, you can add it yourself. This needs a little information from the service's own documentation, usually in a page called API reference or Developer docs.
Click Add Custom API and fill in the form.
Name
Whatever you want to call it — this is just a label so you can recognise it later. "My CRM" is fine.
Base URL (optional)
The web address the service's API lives at. It usually looks like https://api.example.com/v1 and appears at the top of the service's API documentation, often labelled "base URL" or "endpoint".
How AI should use this (optional)
A description, in your own words, of what this service does and when the AI should use it. This is the field that most affects how well the connector works, and it's worth spending a minute on.
Write it as if explaining to a new colleague: what the service is for, and what it can do. If you know the specific actions available, list them. There's room for about 2,000 characters.
A simple example:
Our customer database. Use it to look up customer details and order history.
Available endpoints:
GET /customers - list all customers
GET /customers/{id} - get one customer by ID
GET /orders - list recent orders
You don't need to write it in that format — plain sentences work too. The more the AI knows about what's available, the better it will choose.
Auth Type
How the service expects you to prove who you are. Its documentation will tell you which one it uses. There are four options:
None The service needs no key at all. Uncommon, but some public data sources work this way.
API Key The most common. You provide two things:
- Header Name — the label the service expects, which its documentation will state.
X-API-Keyis typical, and it's what Buildify suggests - API Key — your actual key
Bearer Token Also common. You provide just the token, and Buildify formats it the way services expect. If the documentation mentions "Bearer" or "Authorization: Bearer", choose this.
Custom For services that want something unusual, or more than one value. Add each as a name-and-value pair using Add custom header. Only use this if the documentation asks for something the other three don't cover.
If you can't tell which to pick, search the service's documentation for the word "authentication". Nearly every API documents this in a section by that name, and it'll say which of the above it uses.
Connecting
Click Connect. Buildify immediately tests the connection and tells you the result:
- "Connection successful — API is reachable and responding" — you're done
- "Connection failed — unable to reach the server. Check your URL and credentials." — something's wrong; see below
Editing and removing
Saved custom APIs are listed at the bottom of the tab with their name and address.
- Edit — change any detail, including the key
- Remove — delete the connection entirely
Remember that a custom API also has to be switched on for the project, using the Connectors button next to the chat box.
When the connection fails
Work through these in order — the first two are by far the most common:
Check the Base URL. It should start with https:// and usually end with a version, like /v1. Don't include the specific thing you're fetching — just the base. https://api.example.com/v1 is right; https://api.example.com/v1/customers/123 isn't.
Check the key was pasted whole. Copying from a terminal or email often clips the start or end, or adds a space. Paste it again carefully.
Check the auth type matches the documentation. Choosing API Key when the service wants a Bearer Token fails even though the key itself is correct.
Check the header name. With API Key auth, X-API-Key and Authorization aren't interchangeable — use exactly what the documentation says.
Check the key is still valid. Keys can expire or be revoked. Try it in the service's own dashboard if it offers a test.
Custom MCP servers
MCP is a standard way for a service to offer a set of tools to an AI. If someone has given you an MCP server address to use, this is where it goes.
Unlike an API key, an MCP server isn't something most services offer yet. If you haven't been given a server URL by someone, you almost certainly don't need this tab.
Open the Custom MCP tab and add a server:
- Server Name — a label of your choosing
- Transport Type — HTTP or SSE. Whoever gave you the address will say which; HTTP is the more common
- Server URL — the address, which must start with
https://. Buildify rejects anything else - Icon (optional) — a link to an image, purely cosmetic
- How AI should use this (optional) — a short description of what the server is for and when to use it. You don't need to list its tools; Buildify retrieves those from the server automatically
- Auth Type — the same four options as above. Use whatever the server's owner specified
You can test the connection before saving. As with everything else, switch the server on for the project using the Connectors button next to the chat box.
Keeping custom connectors safe
- Keys and tokens are stored by Buildify and never shown again after saving — you'll only see dots
- Anyone who can edit a Company's connectors can use them, though they can't read the key back
- Remove a connector you no longer use, and revoke the key in the service itself as well
- If you think a key has been exposed, revoke it at the source first. Removing it from Buildify alone doesn't invalidate it