How to make REST API requests in PowerShell

1
# Complete example: Send an SMS with Twilio from PowerShell
2
# Pull in Twilio account info, previously set as environment variables
3
$sid = $env:TWILIO_ACCOUNT_SID
4
$apiKey = $env:TWILIO_API_KEY
5
$apiSecret = $env:TWILIO_API_SECRET
6
$number = $env:TWILIO_NUMBER
7

8
# Twilio API endpoint and POST params
9
$url = "https://api.twilio.com/2010-04-01/Accounts/$sid/Messages.json"
10
$params = @{ To = "+15558675309"; From = $number; Body = "Hello from PowerShell" }
11

12
# Create a credential object for HTTP basic auth
13
$p = $apiSecret | ConvertTo-SecureString -asPlainText -Force
14
$credential = New-Object System.Management.Automation.PSCredential($apiKey, $p)
15

16
# Make API request, selecting JSON properties from the response
17
Invoke-WebRequest $url -Method Post -Credential $credential -Body $params -UseBasicParsing |
18
ConvertFrom-Json | Select sid, body

Let's break down the moving parts of this script.

Set up the credentials and phone number your Twilio account needs before making API requests.

First, export the Twilio account credentials and phone number you need to send an outbound SMS. Find your Account SID and create an API key on your Console dashboard. You can use an existing phone number or buy one in the Console.

There are a number of ways to configure system environment variables on Windows, but you can set user-level environment variables in PowerShell with the following commands. Replace the strings below with the relevant values from your account.

1
[Environment]::SetEnvironmentVariable("TWILIO_ACCOUNT_SID", "your_account_sid", "User")
2
[Environment]::SetEnvironmentVariable("TWILIO_API_KEY", "your_api_key", "User")
3
[Environment]::SetEnvironmentVariable("TWILIO_API_SECRET", "your_api_secret", "User")
4
[Environment]::SetEnvironmentVariable("TWILIO_NUMBER", "+16518675309", "User")

In the example script at the beginning of the article, we access these variables through the $env variable.

Build the endpoint URL for the Messages resource, then define the parameters to send with the request.

$url = "https://api.twilio.com/2010-04-01/Accounts/$sid/Messages.json"

Breaking down the URL:

• https://api.twilio.com: The Twilio API base domain
• 2010-04-01: The Twilio REST API version. This is a stable API version maintained by Twilio. For other endpoints or latest API information, see the Messaging API Reference.
• Accounts/$sid: Your Twilio Account SID (the variable substitution makes this dynamic)
• Messages.json: The endpoint for sending SMS messages, with .json extension to specify JavaScript Object Notation (JSON) response format

Different Twilio products use different endpoints. For example:

• SMS/Messages: /Accounts/{AccountSid}/Messages.json
• Calls: /Accounts/{AccountSid}/Calls.json
• Phone Numbers: /Accounts/{AccountSid}/IncomingPhoneNumbers.json

For the complete list of available endpoints for your use case, refer to the individual resource reference pages (for example, Messaging API, Voice API, Phone Number Management).

Next, we create a hash table with the POST parameters we need to send with our request.

$params = @{ To = "+15558675309"; From = $number; Body = "Hello from PowerShell" }

Purpose of each parameter

• To: The phone number to send the SMS to (replace +15558675309 with the actual recipient's phone number in E.164 format)
• From: A Twilio-powered phone number the SMS message will come from (this comes from your $number environment variable)
• Body: The actual text of the outbound message

Next, create a PSCredential object to pass your HTTP Basic Authentication credentials to Twilio. We need to create a PSCredential to pass into the Invoke-WebRequest command.

Now that we have all our configuration ready, we use the Invoke-WebRequest command to send the SMS. The script uses the ConvertFrom-Json command to parse the JSON response from the Twilio API and the Select command to extract specific properties.

For PowerShell 5.1 and earlier, include -UseBasicParsing to prevent creating a Document Object Model (DOM) from the results and to avoid errors on systems without Internet Explorer installed. In PowerShell 6.0 and later, this flag is ignored.

1
Invoke-WebRequest $url -Method Post -Credential $credential -Body $params -UseBasicParsing |
2
ConvertFrom-Json | Select sid, body

Complete script:

When running this script, you may encounter common errors. Here are solutions to resolve them:

With this code, you can make an authenticated REST API request from PowerShell and send an SMS message without leaving the shell.

For additional guidance and examples:

• Send Your First SMS: Get started with our SMS quickstart guide.
• Twilio Messaging API Reference: Explore all available Twilio messaging endpoints.
• Create an API Key: Manage your authentication credentials.
• PowerShell documentation: Learn more about PowerShell scripting.