How do I get my PayPal API signature?

You get a PayPal API signature from your PayPal business account: open Account Settings, then Account access, click Update next to API access, choose Manage API Credentials in the NVP/SOAP API Integration (Classic) section, then Request API signature and Agree and Submit. The signature works together with an API username and API password, and the three values authenticate requests to PayPal's NVP/SOAP APIs.

Two things to know before you start:

• PayPal has put NVP/SOAP under a deprecation notice. Its developer page heads the notice "Deprecation notice" and says "PayPal's NVP/SOAP APIs are legacy APIs, but PayPal continues to support them", then points new integrations to its latest tools and existing ones to its upgrade hub (PayPal Developer: Create and manage NVP/SOAP API credentials, last updated August 17, 2026). PayPal's current REST APIs use a client ID and client secret instead (see below).
• Billed connects to PayPal with your PayPal keys. That's what Billed's PayPal integration page says. To find out which keys to use, ask Billed support.

The steps below are from PayPal's own documentation, checked on October 29, 2026. If a menu name doesn't match what you see, use PayPal's direct link in step 2.

How to request a PayPal API signature

From PayPal's developer documentation:

1. Log in. For live credentials, log in to your PayPal business account at www.paypal.com. For test credentials, log in to the PayPal sandbox at www.sandbox.paypal.com with a sandbox business account.
2. Open API access. Hover over your name and click Account Settings. On the Account access page, click Update next to API access. PayPal's help center also links straight to this page, called Your Payment API Credentials (PayPal Help: How do I request an API signature?).
3. Open the NVP/SOAP section. Click Manage API Credentials in the NVP/SOAP API Integration (Classic) section. If you have already generated an API signature, this shows the existing signature information. To generate a new one, click Remove to delete the existing signature first.
4. Request the signature. Select Request API signature, then click Agree and Submit.
5. Copy your credentials. PayPal describes an API signature credential as your API username, API password and signature, so copy all three. Paste them only into the tool that asked for them.

PayPal says you can generate NVP/SOAP credentials for any PayPal Business or Premier account. Credentials you request in the sandbox are test credentials; for real payments, request them from your live PayPal business account.

API signature or API certificate?

The NVP/SOAP APIs accept two kinds of credential, and an account can have only one of them (PayPal Help: "It isn't possible to have both an API signature and certificate").

• API signature: API username, API password and a signature string. This is what a tool means when it asks for a "signature".
• API certificate: API username, API password and a certificate file. PayPal recommends certificates "for security reasons", and its certificates expire every three years, so they must be renewed (PayPal Developer).

If your account already has a certificate, PayPal says it must be removed before you can request a signature. Before you remove it, check whether any of your existing tools still sign in with that certificate.

If a tool asks for a client ID and secret instead

A client ID and client secret are credentials for PayPal's REST APIs, not an API signature. PayPal's REST APIs authenticate with OAuth 2.0 access tokens, which you get by exchanging your client ID and secret. To find them, log in to the PayPal Developer Dashboard, select Apps & Credentials, and copy the client ID and client secret for your app. New accounts come with a Default Application in the REST API apps section (PayPal Developer: Get started with PayPal REST APIs, last updated August 17, 2026). PayPal notes that you need a PayPal Business account to go live.

Worked example: which PayPal credential do you need?

Dana runs a small print shop (an example, not a real customer). Three tools ask her for PayPal details:

1. An older website shopping cart asks for "API username, API password and API signature". That's an NVP/SOAP integration, so she follows the steps above. On the Manage API Credentials page she finds an API certificate set up years ago by a former developer. Because PayPal allows only one of the two, she confirms that nothing else uses the certificate, removes it, requests a signature, and pastes the three values into the cart.
2. A custom booking app her developer is building asks for a "client ID and secret". That's the REST API, so her developer copies them from Apps & Credentials in the Developer Dashboard, not from the API access page.
3. Billed, which she uses to invoice wholesale clients, connects to PayPal with her PayPal keys. She asks Billed support which keys it needs before she requests anything new.

Because PayPal has NVP/SOAP under a deprecation notice, Dana also asks the cart's vendor whether it supports PayPal's current integration, using PayPal's upgrade hub as the starting point.

Connecting PayPal to Billed

Billed's PayPal integration page says Billed connects to PayPal with your PayPal keys. For help connecting your PayPal account to Billed, contact Billed support.

With PayPal connected, Billed's features page says you can "Integrate Paypal with Billed App and accept Paypal payments on invoices." To offer card payments as well, see the Stripe integration.

Keep your credentials private

API credentials let software act on your PayPal account, so treat them like a password. Don't paste them into email, chat or shared documents. If you think they have been exposed, remove the signature on the Manage API Credentials page, request a new one, and update the tool that uses it. PayPal gives the same advice for the REST client secret: "Keep this secret safe" (PayPal Developer).

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Frequently Asked Questions

Where do I find my PayPal API signature?

In your PayPal business account, go to Account Settings, then Account access, and click Update next to API access. Then click Manage API Credentials in the NVP/SOAP API Integration (Classic) section. If a signature already exists, PayPal shows it there; if not, select Request API signature, then Agree and Submit.

Which PayPal accounts can get an API signature?

PayPal's developer documentation says you can generate NVP/SOAP API credentials for any PayPal Business or Premier account. For testing, use a sandbox business account at sandbox.paypal.com.

Is PayPal's API signature being phased out?

PayPal's developer page puts NVP/SOAP under a "Deprecation notice": it says the NVP/SOAP APIs are legacy APIs and that PayPal continues to support them (checked October 29, 2026). PayPal recommends its latest tools for new integrations and its upgrade hub for existing ones.

Is an API signature the same as a client ID and secret?

No. The API signature, with its API username and password, is for the legacy NVP/SOAP APIs. PayPal's REST APIs use a client ID and client secret from Apps & Credentials in the PayPal Developer Dashboard.

Can I have an API signature and an API certificate at the same time?

No. PayPal says an account can't have both. If you have a certificate, it must be removed before you can request a signature.

What does Billed need to connect PayPal?

Billed's PayPal integration page says Billed connects to PayPal with your PayPal keys. To find out which keys to use, ask Billed support.