Amazing that there is still not an online process for renewal, I guess we have to keep the post office in business
Also as the PP said the passport card is a great option - only drawback it is only good for 5 years - so more renewals via mail.
I've been able to renew my EU Passport and card on-line for many years, you can even take an updated photo at home and upload it and its validated and sized/cropped correctly - turn around is also very quick - was under 2 weeks.
I've never used a post office for passports. I went to the San Francisco Passport Agency the first time but have renewed by mail or online ever since. My family has never used a post office, although my wife needed one on short notice and our kid did once. But our kid's first one was done at a university recreational gym. It was great since at the time they didn't require reservations and were also available on Saturdays.
There was an online process. The first one (several times in the past) was a "renewal only" for passport cards, although anyone with a passport book was eligible for said renewal as long as it was within the issuance requirements (15 years for a standard 10 year adult passport).
I got mine (passport book and card) last year through an online renewal. The State Dept went through several pilot program periods where they had a cap on the number of online applications, but now they've stopped it and claim that it will come back after they've applied everything they've learned. The tricky thing was getting the photo right, as their online cropping tool was pretty bad. I found an online passport photo editing tool that just created a single photo JPEG (and not one meant for making prints) and submitted it that way where I didn't need to do any cropping.
The Limited Release is Currently Paused
On March 8, 2023, we paused our limited release of the online renewal service, so that we can introduce improvements based on customer feedback.
During our limited release, over 500,000 customers volunteered to submit their applications online and test our system. We look forward to launching the enhanced application in a full, nationwide release.
They did have some caveats to reduce the number of people trying out the pilot program. Mail-in renewals can be done almost any time with a valid passport (or passport card) as well as one within 15 years of issuance (i.e. expired up to 5 years). However, the online application was limited to those with at least one of a passport (or card) that would expire within 1 year or was expired less than 5 years.
I did it in October 2022 where my passport card had expired in 2019 and my passport book had expired in August 2020. But both were expired less than 5 years so I was OK to use the online application. There were also a few weird things about it like when I checked my status there were a lot of entries that were blank, but showed up fine when I received my passport. But it was nice because I didn't need to make a photo print (and Costco no longer does prints) as well as not needing to mail anything out nor physically submit my passport. Also - my (1st gen) passport card had some issues with durability where the layers started cracking and delaminating, and I was worried that it might be considered "damaged" where it wouldn't be eligible for mail-in renewal.