Debug an HTTP client with a temporary echo endpoint
See the method, query, headers and body your HTTP client actually sends, with a private temporary echo URL and a readable request preview.
Read the guide →Less setup. Better understanding.
Practical guides for the small tasks between an idea and a working integration, each with examples you can run.
Latest · HTTP debugging
More practical guides.
API testing
Test complete frontend flows with a stateful CRUD mock API
Create realistic test records, exercise create and edit flows, restore seed data, and share a temporary CRUD API with clear access and lifecycle controls.
API testing
Build a reusable API test scenario with variables and checks
Turn a few manual API requests into a repeatable scenario with response checks, captured IDs, separate secrets and a readable report you can export.
Validation basics
How to format and validate JSON without uploading it
Paste JSON into a formatter that runs in your browser, so nothing is uploaded. Learn what validation catches, why big numbers change, and how to script it.
API development
How to decode a JWT safely, and what a decoder cannot tell you
Decode a JWT locally to read its header and claims, then verify it in your own code. Decoding shows what a token says; only verification proves who issued it.
AI & MCP
How to test an AI agent’s tool calls with a mock MCP server
Point your agent at a temporary MCP server with fixed tools and static replies, then check how it calls tools, handles bad arguments, and recovers from errors.
Files & access
How to share a file from the terminal with a one-time link
Upload a file with curl or the socket-help CLI, limit it to one download, and send the token separately. The contents are removed once that download happens.
Integration testing
How to test retries, backoff and timeouts in an HTTP client
Create a mock endpoint that returns 429 with Retry-After, 503, or a slow reply, then confirm your client backs off, gives up, and times out the way you expect.
Images & design
Generate useful images and avatars for a real interface
Choose dimensions, styles, palettes and deterministic variations, then export editable SVG or raster PNG for your layout and test data.
Audio & music
Make a custom instrumental loop with melody, bass and drums
Build an editable arrangement, balance its instruments, understand the export format and reproduce the result through the socket.help API.
Audio & music
Free music for prototypes: what the library includes and how CC0 works
Stream original instrumentals, download editable WAV loops, use byte-range playback and understand the scope of the built-in tracks’ CC0 terms.
Payment testing
Credit card generators for testing: what the output means
Create clearly labeled credit-card fixtures for checkout tests. Understand sandbox numbers, sample CVCs, PaymentMethod identifiers, and checksum limits.
Payment testing
Using debit-card test data in a checkout flow
Generate debit-card sandbox fixtures, preserve the funding label in tests, and check your checkout without using real banking details.
Payment testing
Prepaid-card fixtures for payment integration tests
Create a prepaid sandbox fixture and test funding-aware UI. Understand reusable numbers, provider-specific behavior, and what the generator does not simulate.
Validation basics
What a Luhn card-number check can and cannot tell you
Understand card-number checksum validation, test valid and invalid inputs, and avoid treating a passing Luhn check as proof of a real or usable payment card.
Integration testing
How to test webhooks without a server
Capture a test callback, inspect its real payload, and debug delivery without deploying a receiver or exposing localhost.
Files & access
Public or private file sharing: which should you use?
Choose the right access for a temporary file, keep tokens out of links, and understand one-time downloads, previews, and expiry.
API development
Test API errors before your users find them
Use predictable mock responses to test loading states, validation errors, server failures, and delays without depending on a live upstream API.
Choosing between tools?
See where socket.help fits alongside established alternatives.