Twitter has formally announced its revamped API tiers a month and a half after new CEO Elon Musk promised a big shake up of the system. In a thread, the company’s official developer account listed three tiers — free, basic, and enterprise — and provided some details on their prices and read and write limits. It also linked to signup pages, which offer links to get started with the first two tiers, and to express an interest in the third.

The company says older tiers will be depreciated “over the next 30 days.” Here’s a short summary of the three replacements (which can also be found on Twitter’s website): 

Responding to Twitter’s announcement, some developers said they’d have to kill their projects or pass the fees onto users. Accountanalysis developer Luca Hammer said he would have to shut down his tool designed to help journalists and academics analyze Twitter accounts. Daniel Nguyen, whose Ktool software sends Twitter threads to be read on Kindle said the changes mean he’ll either have to stop supporting Twitter, or increase prices.

Another developer, who asked to remain anonymous, called the free tier “terrible” because of the limited post cap, and the apparent inability to read simple information like tweets, likes, and follows from the platform.

However, other developers, such as the team behind tweet scheduling service Typefully said they can afford the new pricing and so will continue supporting the platform. “But this would have totally killed us 1 year ago or back when we started,” Typefully co-founder Francesco Di Lorenzo tweeted.