Best Practices for Developing On Twilio
Here’s a summary of a number of best practices we’ve found that work well in
the development of your Twilio applications.
This section covers pro tips related to handling inbound Twilio requests and
responding to them with TwiML.
- Use a helper library to generate your TwiML and avoid simple typo errors.
- Make use of Fallback URLs for phone numbers and TwiML apps to prevent your
users from hearing the dreaded “We’re sorry - an application error has
- If you’re looking to maintain any state around calls, be sure to leverage
Status Callback URLs to get asynchronous notifications of completed calls.
Using the REST API
Here we cover a few helpful tips for using the REST API for outbound Twilio
requests like placing calls or sending text messages.
- Make use of the exceptions available in your helper library to prevent
malformed phone numbers or missing permissions from causing fatal errors.
Try/catching all outbound REST requests against these exceptions give you an
easy way to handle errors gracefully and log for debugging later.
- If making a large number of requests - like when sending text messages to a
group of contacts - make use of a task queue like Celery to send
- Use the new Usage API to reduce API calls for summary statistics on Twilio
Using Twilio Client
touch with your users.
- Be sure to include a visual cue for first time users to click “Allow” in the
pop-up permissions dialog.
- Set your token expiration to a value that makes sense for your use case. By
default, this is an hour.
- Use the parameters property to surface important details to your users like
who is calling and what is dialed.
Security is critical to telephony applications - here’s some tips on using
- Never bundle your AccountSid and AuthToken in a client-side application, even
if it is compiled.
- Always generate Twilio Client capability tokens server-side.
- Use Digest Authentication and SSL in concert for your TwiML URLs to make
Twilio authenticate with your web server.
- Use Request Validation to further confirm that requests are legitimately
coming from Twilio.
Testing your apps before you go into production is always wise. Here are a few
tips to make sure your tests work well.
- If mocking the Twilio REST Client, be sure mock the resource instead of the
client itself for best effect.
- Simulate Twilio in your test web client by matching the parameters found in a
- Test early, test often. It’s good for you!