Email API Quickstart: How to Send Email with Python

In this quickstart, you'll learn how to send your first email using the Twilio SendGrid Mail Send API and Python.

Prerequisites

Be sure to perform the following prerequisites to complete this tutorial. You can skip ahead if you've already completed these tasks.

1. Sign up for a SendGrid account.
2. Enable Two-factor authentication.
3. Create and store a SendGrid API Key with Mail Send > Full Access permissions.
4. Complete Domain Authentication.
5. Install Python.

Skip the prerequisites

Sign up for a SendGrid account

When you sign up for a free SendGrid account, you'll be able to send 100 emails per day forever. For more account options, see our pricing page.

Enable Two-factor authentication

Twilio SendGrid requires customers to enable Two-factor authentication (2FA). You can enable 2FA with SMS or by using the Authy app. See the 2FA section of our authentication documentation for instructions.

Create and store a SendGrid API key

Unlike a username and password — credentials that allow access to your full account — an API key is authorized to perform a limited scope of actions. If your API key is compromised, you can also cycle it (delete and create another) without changing your other account credentials.

Visit our API Key documentation for instructions on creating an API key and storing an API key in an environment variable. To complete this tutorial, you can create a Restricted Access API key with Mail Send > Full Access permissions only, which will allow you to send email and schedule emails to be sent later. You can edit the permissions assigned to an API key later to work with additional services.

Once your API key is assigned to an environment variable — this quickstart uses SENDGRID_API_KEY — you can proceed to the next step.

export SENDGRID_API_KEY=<Your API Key>

Verify your Sender Identity

To ensure our customers maintain the best possible sender reputations and to uphold legitimate sending behavior, we require customers to verify their Sender Identities by completing Domain Authentication. A Sender Identity represents your 'From' email address—the address your recipients see as the sender of your emails.

Python

Before installing Python and sending emails, you can see if you already have a version on your machine.

Python version check

Check your Python version by opening your terminal (also known as a command line or console) and typing the following command.

python --version

If you have Python installed, the terminal should print something like the following output.

Python 3.8.5

Install Python

If you do not already have a version of Python installed, visit the Python website to download and install a version appropriate for your operating system.

Starting the project

Using a Twilio SendGrid helper library is the fastest way to deliver your first email.

Start by creating a project folder for this app. You can name the project anything you like. We use sg_quickstart in the following examples.

mkdir sg_quickstart

Next, navigate into the sg_quickstart directory where you will complete the rest of the tutorial.

cd sg_quickstart

Initialize your project

The pip package manager was included when you installed Python. You can use pip to install the Twilio SendGrid helper library and save it as a project dependency. If you want to verify that pip is installed, you can type the following into the terminal.

pip --version

The terminal should print something like the following output.

pip 20.1.1 from /usr/locallib/python3.8/site-packages/pip (python 3.8)

Install the helper library

To install the Twilio SendGrid helper library, type the following command into the terminal.

pip install sendgrid

The terminal should print something like.

Collecting sendgrid
  Using cached sendgrid-6.4.6-py3-none-any.whl (73 kB)
Requirement already satisfied: python-http-client>=3.2.1 in /usr/local/lib/python3.8/site-packages (from sendgrid) (3.3.1)
Requirement already satisfied: starkbank-ecdsa>=1.0.0 in /usr/local/lib/python3.8/site-packages (from sendgrid) (1.0.0)
Installing collected packages: sendgrid
Successfully installed sendgrid-6.4.6

How to send an API email with Python

You're now ready to write some code and send emails with Python. First, create a file in your project directory. You can use app.py.

Complete code block

The following Python block contains all the code needed to successfully deliver a message with the SendGrid Mail Send API. You can copy this code, modify the from_email and to_email variables, and run the code if you like. We'll break down each piece of this code in the following sections.

import sendgrid
import os
from sendgrid.helpers.mail import Mail, Email, To, Content

sg = sendgrid.SendGridAPIClient(api_key=os.environ.get('SENDGRID_API_KEY'))
from_email = Email("test@example.com")  # Change to your verified sender
to_email = To("test@example.com")  # Change to your recipient
subject = "Sending with SendGrid is Fun"
content = Content("text/plain", "and easy to do anywhere, even with Python")
mail = Mail(from_email, to_email, subject, content)

# Get a JSON-ready representation of the Mail object
mail_json = mail.get()

# Send an HTTP POST request to /mail/send
response = sg.client.mail.send.post(request_body=mail_json)
print(response.status_code)
print(response.headers)

Build your API call

Your API call must have the following components:

• A host (the host for Web API v3 requests is always https://api.sendgrid.com/v3/)
• An API key passed in an Authorization Header
• A request (when submitting data to a resource via POST or PUT, you must submit your request body in JSON format)

In your app.py file, import the SendGrid helper library. The library will handle setting the Host, https://api.sendgrid.com/v3/, for you.

import sendgrid

Next, use the API key you set up earlier. Remember, the API key is stored in an environment variable, so you can use the os.environ.get() method to access it. This means we also need to import Python's os library.

import os

Assign the key to a variable named sg using the helper library's SendGridAPIClient() method. The helper library will pass your key to the v3 API in an Authorization header using Bearer token authentication.

sg = sendgrid.SendGridAPIClient(api_key = os.environ.get('SENDGRID_API_KEY'))

Now you're ready to set up the from_email, to_email, subject, and message body content. These values are passed to the API in a "personalizations" object when using the v3 Mail Send API. You can assign each of these values to variables, and the SendGrid library will handle creating a personalizations object for you.

First, import the library's Mail, Email, To, and Content classes.

from sendgrid.helpers.mail import Mail, Email, To, Content

With the helpers imported, define and assign values for from_email, to_email, subject, and content variables. Assigning an email address like from_email = "sender@example.com" will work. However, the constructors imported in the previous step allow you to pass data to them to be sure your final message is formatted properly. Be sure to assign the to_email to an address with an inbox you can access.

Note that the Content() helper takes two arguments: the content type and the content itself. You have two options for the content type: text/plain or text/html. The second parameter will take the plain text or HTML content you wish to send.

from_email = Email("test@example.com")  # Change to your verified sender
to_email = To("test@example.com")  # Change to your recipient
subject = "Sending with SendGrid is Fun"
content = Content("text/plain", "and easy to do anywhere, even with Python")

To properly construct the message, pass each of the previous variables into the SendGrid library's Mail constructor. You can assign this to a variable named mail. You can then use the Mail constructor's get() method to get a JSON-ready representation of the Mail object.

mail = Mail(from_email, to_email, subject, content)

# Get a JSON-ready representation of the Mail object
mail_json = mail.get()

Lastly, you need to make a request to the SendGrid Mail Send API to deliver your message.

The helper library uses SendGrid's python-http-client library to construct the request URL by chaining together portions of your desired path. The path to the SendGrid v3 Mail Send endpoint is https://api.sendgrid.com/v3/mail/send. The helper library sets the client for you, so the https://api.sendgrid.com/v3 portion is taken care of by typing sg.client. The next parts of the path are /mail and /send. You can chain the words mail and send onto client to build the rest of the URL.

With the URL built, python-http-client then allows you to chain on the type of HTTP request you wish to make with a method matching the name of the HTTP verb appropriate for your desired endpoint. To send a message, you should make an HTTP POST request, so you can use post(). The post() method takes a request_body, which you should set to the JSON version of your message (remember, this JSON-ready version is stored in the mail_json variable). You can assign this full call to a variable named response and print the response status code and headers.

# Send an HTTP POST request to /mail/send
response = sg.client.mail.send.post(request_body=mail_json)
print(response.status_code)
print(response.headers)

With all this code in place, you can run your app.py file with Python to send the email.

python app.py

If you receive a 202 status code printed to the console, your message was sent successfully. Check the inbox of the “to_email” address, and you should see your demo message.

If you don’t see the email, you may need to check your spam folder.

Troubleshooting

If you receive an error message, you can reference our response message documentation for clues about what may have gone wrong.

API Response messages

All responses are returned in JSON format. We specify this by sending the Content-Type header. The Web API v3 provides a selection of response codes, content-type headers, and pagination options to help you interpret the responses to your API requests.

Next Steps

This is just the beginning of what you can do with our APIs. To learn more, check the resources below.

• API Reference
• Sending Email with Dynamic Transactional Templates
• Getting Started with the Event Webhook
• The Email Activity Feed
• Sender Authentication
• Twilio SendGrid helper library for Python