Slashbin vs PostBin
First, which PostBin? There are several unrelated open-source projects on GitHub using the name, but the hosted service people mean is PostBin at postb.in (opens in a new tab). The toptal.com/developers/postbin URL that most articles link to 301-redirects there, so both front doors resolve to the same tool. That's the one this page compares against.
It isn't the same shape of product as Slashbin, and that's the point. PostBin gives you a throwaway URL that collects whatever you send it, so you can look at the request — or assert on it from a test suite. Its own notes are explicit about the trade: "Each bin will expire after 30 mins." Slashbin is the piece you keep afterwards: a gateway that transforms, validates, and delivers webhooks to real destinations, with retries and replay when something breaks.
If you need to see one request right now, PostBin is faster than us and always will be.
What PostBin is better at
- Zero signup, zero configuration, zero cost. Click "Create Bin", get a URL, paste it into a vendor's dashboard. No account, no card, no project. Slashbin requires an account and a card for its 14-day trial — for a ten-second question, that's the wrong trade.
- An API designed for automated tests.
POST /api/bincreates a bin from your CI job and returns itsbinIdandexpirestimestamp;GET /api/bin/:binId/req/shiftpops requests off the front in order, so a test can assert on what your code sent without tracking request IDs. PostBin's own docs call the API "the killer feature," and it is — Slashbin has no equivalent, because it isn't built to be an assertion target. - Nothing to clean up. The 30-minute expiry is a feature: no configuration to migrate, no schema to maintain, nothing left running after the test.
What Slashbin is better at
- Outliving the debugging session. A PostBin bin is gone in half an hour by design. Slashbin is infrastructure your production pipeline depends on tomorrow.
- Transform and validate against one schema. Every inbound event is reshaped and checked against a Golden Model you define. Downstream code reads one canonical shape no matter which vendor sent it, and a renamed field fails loudly at the boundary instead of quietly corrupting what's downstream.
- Deliver to real destinations with per-destination isolation. One inbound event fans out to every consumer that needs it, and a failing destination is circuit-broken on its own without back-pressuring the others. See Fan-out.
- Retries and replay from stored history. The original payload is kept byte-for-byte. When you fix a transform, Replay re-runs stored events through the current pipeline — you don't ask the vendor to re-send.
- A per-attempt delivery log. Response code, body, timing, and retry count for every attempt to every destination — the evidence that answers "did this event actually land?" three weeks later.
When to use which
- Is this vendor even sending anything, and what does it look like? → PostBin. Faster than signing up for anything, ours included.
- My integration test needs to assert on an outbound request. → PostBin's API. That's what it's for, and Slashbin doesn't do it.
- A production pipeline I rely on tomorrow. → Slashbin. A URL that expires in 30 minutes can't be that.
- Every vendor sends a different shape and my downstream code is full of adapter glue. → Slashbin. One Golden Model, validated at ingest, is the whole point.
- I need to prove what happened three weeks ago. → Slashbin. Stored payload, stored transform result, stored delivery attempts.
The usual sequence is a bin during vendor onboarding, a gateway once the integration is real.
Feature comparison
Verified on 2026-07-30 against the live service at postb.in (opens in a new tab) and its API documentation (opens in a new tab); toptal.com/developers/postbin 301-redirected to that same host on the same date. Slashbin rows verified against the live product and pricing page that day.
| Capability | PostBin | Slashbin |
|---|---|---|
| Instant capture URL, no signup | Yes | No — account required |
| Price | Free | Lite $10/mo (5,000 webhooks) |
| How long the endpoint lives | 30 minutes | For as long as your account does |
| Retention / replay window | None — the bin and its requests are deleted with it | 7-day on Lite, 30-day on Pro |
| API for creating and draining bins from CI | Yes — POST /api/bin, req/shift | Not the product model |
| Transform and validate against a canonical schema | Not the product model | Yes — Golden Model |
| Deliver one event to N destinations with per-destination filters | Not the product model | Yes — Fan-out |
| Retries with backoff and a dead-letter queue | Not the product model | Yes |
| Replay a stored raw payload through the current pipeline | Not the product model | Yes — Replay |
| Per-attempt delivery log (response code, body, timing) | Not the product model | Yes |
"Not the product model" means the tool isn't trying to do that job. PostBin is a disposable capture surface with a test-automation API; it is not a delivery gateway and doesn't claim to be. That's a different shape of product, not a defect.
Related reading
- All comparisons — every tool Slashbin is compared against, with a one-line note on who each page is for.
- Slashbin vs mockbin — the fuller treatment of the same category, including what happened to
mockbin.org. - Slashbin vs webhook.site — the same boundary against the most feature-complete inspection tool.
- Webhook ETL — the category Slashbin fits in, and why point-to-point handlers stop scaling.
- Replay — re-drive a stored event through the current transform + delivery pipeline.