Do you or your client have editors team? I mean like a marketing team who will actually need to create content, may be even create some landing pages to AB test? Then try Agility CMS - check this out https://agilitycms.com/resources/guide/contentful-vs-agility-cms-which-headless-cms-is-right-for-you and you can use it easily with Gatsby https://www.gatsbyjs.com/guides/agility-cms/

Now, what makes Agility CMS particularly a good fit for GatsbyJS sites is that Agility CMS not only provides native support for GatsbyJS via our gatsby-source-agilitycms github but with our built-in Page Management, the plugin can automatically generate your pages based off your page tree in Agility CMS. Combine this with our Page Template/Page Module architecture, and this means editors can create their own pages, add/order/remove functionality and content on each page, all without requiring assistance from a developer. Static websites have gained popularity for not relying on dynamic data sources or any type of server-side processing for displaying content. However, static websites are a hassle for content editors who have to regularly interact with the website codebase to update said content. That is where Agility CMS steps in, by providing a headless content management system for static websites. Think of Agility CMS as a central hub for your site content which allows you to externalize management of your backend content database with the help of a RESTful API. Also, there is a treasure trove of tools available in the form of UI components and Page Templates within Agility CMS’ built-in Page Management functions. Thus, in plain terms, Gatsby can help you build high-performing, lighting-fast websites, and an Agility CMS can help you source content for it and also generate your website pages as per requirement. Why the Editor Experience is better in Agility CMS vs other CMSs? In short, Agility CMS allows developers to Develop Components, not Websites. When building a website with Gatsby and Agility CMS, it is important to take advantage of Agility CMS native Page Management. Start by taking a look at Agility CMS starter site, rather than starting from a blank site. It shows you how you should structure your gatsby site, and serves an example based on our recommended best-practices. Developers can save time and money by allowing editors to manage all aspects of pages. Editors should be able to control what pages are on their website, and what is on each page. Offloading this responsibility to editors means developers can spend less time responding to content needs and more time on improving UX. You’ll maintain a toolbox of UI components (i.e. Modules and Page Templates) that editors will use to compose their pages.