Based on our record, Beeceptor seems to be more popular. It has been mentiond 3 times since March 2021. We are tracking product recommendations and mentions on Reddit, HackerNews and some other platforms. They can help you identify which product is more popular and what people think of it.
I don't what you mean by the custom server for portswigger but if you mean Burp collaborator then you can use https://beeceptor.com as its alternative. - Source: Reddit / 5 months ago
Beeceptor - Mock a rest API in seconds, fake API response and much more. Free 50 requests per day, public dashboard, open endpoints (anyone having link to the dashboard can view requests and responses). - Source: dev.to / 6 months ago
In any extent, end-points to dump the data will do as HTTP transmission all end as non-binary (besides file uploads). Sites like httpbin and the likes are helpful. For example, with tools like Beeceptor or pipedream you can mock APIs, proxy calls, log, filter and bounce calls with or without payloads... Basically anything that comes to your mind. - Source: Reddit / 8 months ago
MockServer - Easy mocking of any system you integrate with via HTTP or HTTPS.
Webhook.site - Instantly generate a free, unique URL and email address to test, inspect, and automate (with a visual workflow editor and scripts) incoming HTTP requests and emails.
WireMock - WireMock - a web service test double for all occasions.
RequestWatch - Inspect and debug HTTP requests
RoboHydra - RoboHydra is a web server designed to help you test any kind of HTTP client:
Postman - The Collaboration Platform for API Development