A project token is scoped to just an environment in a project. But a service belongs to all environments of the project. Therefore, you won't be able to use the project token to create a service. I recommend using the team token for it. If the Team-Access-Token token header doesn't work, try to use it the same way you use an account token, and it should work.Creating a service in a project might take some time to show up in the UI. You can confirm its existence by using the query below. If you are still unable to see it after a long time, I would recommend deleting it using API and re-creating it.The following is what I use to debug API issues.query readProject { project( id: "YOUR_PROJECT_ID_HERE" ) { id volumes { edges { node { id name volumeInstances { edges { node { id serviceId environmentId } } } } } } services { edges { node { id name serviceInstances { edges { node { id region environmentId numReplicas latestDeployment { id meta } source { repo image } domains { customDomains { id domain status { cdnProvider certificateStatus dnsRecords { currentValue fqdn hostlabel purpose recordType requiredValue status zone } } } serviceDomains { id domain suffix targetPort } } } } } } } } } }If you are using the API to provision infrastructure, I would recommend the following Terraform provider. https://github.com/terraform-community-providers/terraform-provider-railway

A serviceInstance belongs to an environment. service belongs to the project. When you create a service, it creates a service and for each environment creates a serviceInstance (unless specified otherwise by giving it environmentId as an input, but this only works for PR environments). Have you tried with the team token using Authorization: Bearer <token> header? I just tested and it worked.