CheckcraftAPI and log testing guides
Get help with your first test →
Start with a task, inspect an actual result and repeat a check with downloadable sample data.
Guides available · 63
API testing software without writing code
The example expects status to be OK. A second input changes it to ERROR and the same test fails. You can try this without connecting to a working API.
Open guide →Practical guideHow to create API tests without code
You will import a test case, run it against two inputs and see the exact field that differs.
Open guide →Practical guideAutomate API and log checks with Kibana
The request identifier selects the operation to inspect, and saved rules validate fields from the matching log data.
Open guide →Practical guideFind request logs by traceId in Kibana
You will know which value and field the search uses and can turn the selected log data into a repeatable check.
Open guide →Practical guideValidate required and unexpected JSON fields
The test checks required values and rejects an unexpected property. Its broken input demonstrates a real failure.
Open guide →Practical guideValidate every element of a JSON array
The downloadable example contains 1000 items. The broken input puts a defect at the end so you can verify that the test reaches it.
Open guide →Practical guideHTTP 200 but the result is wrong
The example changes a business status while keeping the test itself unchanged, showing why response fields need their own rules.
Open guide →Practical guideValidate JSON and XML API responses
You will separate data extraction from value checks and see how a deliberate mismatch appears in the report.
Open guide →Practical guideCreate API test drafts with local AI
You can review proposed test cases before adding them, then run the saved rules on passing and deliberately failing data.
Open guide →Practical guideImport cURL, OpenAPI and Postman requests
You can inspect an imported request, send it to a test environment and add explicit response checks.
Open guide →Practical guideChain API requests with extracted variables
The example extracts an identifier and compares it with a value in another part of the data. Use the same principle in a request sequence.
Open guide →Practical guideCreate a local API mock server
You can configure a local route, call it from an HTTP request and inspect the incoming request history.
Open guide →Practical guideRun API tests in Jenkins and CI pipelines
You will prepare a suite and identify its runtime, secrets and report settings before enabling unattended execution.
Open guide →Practical guideA Postman alternative for API and log checks
You can import a familiar request, add a field rule and inspect a log-based check before deciding whether Checkcraft fits your work.
Open guide →Practical guideCheckcraft security and data handling
You can separate the offline example, configured service connections and account operations before deciding how to use the application.
Open guide →Practical guideConfigure API request authentication
You will inspect the configured authentication and response status before adding business-result checks.
Open guide →Practical guideGenerate test drafts from documentation and screenshots
You will check the recognized material, review the proposed steps and prove the resulting test with a deliberate error.
Open guide →Practical guideCreate XML response tests without code
The example validates XML content and a tag whitelist. Its broken input makes a saved rule fail.
Open guide →Practical guideTest API totals, discounts and calculations
The example sums item amounts, stores the expected total in a variable and compares it with the returned total.
Open guide →Practical guideCreate conditional and negative API tests
The example checks an error code when status is ERROR and demonstrates a failure when that code is wrong.
Open guide →Workflows for QA, analysts and integration engineers
API test automation for manual testers without code
Turn a manual response check into a repeatable Checkcraft test. Sample JSON, a saved test case and a deliberate failure to verify the rule.
Read the guide →Practical workflowAPI testing for systems analysts from requirements
Validate an API calculation against a requirement. Convert an order example into repeatable checks and share discrepancies with a developer.
Read the guide →Practical workflowAPI regression testing and response comparison
Compare JSON API responses before and after a release, exclude requestId and timestamp in Checkcraft Pro, and repeat checks after a fix.
Read the guide →Practical workflowAPI test reports in HTML, TXT and JUnit XML
Save Checkcraft reports, inspect expected and actual values and export JUnit XML from CI runs.
Read the guide →Practical workflowIntegration testing across API, logs and database
Verify an HTTP request, correlated logs and a database record for one operation. A workflow for integration engineers and architects.
Read the guide →Practical workflowValidate API status codes, headers and response time
Check HTTP status codes, Content-Type, JSON body fields and response time as independent assertions in Checkcraft.
Read the guide →Practical workflowGraphQL API testing and validation of data and errors
Set query and variables in Checkcraft and distinguish HTTP success from GraphQL errors and partial data.
Read the guide →ProData-driven API testing with CSV and Excel exports
Prepare CSV variables and expected responses for Checkcraft Pro, run multiple rows and retry failures. Excel data uses a CSV export.
Read the guide →ProVerify database persistence after an API request
An API reports success but its record is missing. Verify POST results with a parameterized SELECT and database polling in Checkcraft Pro.
Read the guide →Practical workflowHow to write an API bug report a developer can reproduce
Document the request, expected and actual API response, reproduction steps and Checkcraft report. Copy a bug report template and use sample failing JSON.
Read the guide →Practical workflowCheck an API response online, no install or sign-up
Paste an API response, set rules and get a report right in your browser. Nothing is sent anywhere. Save the check as a file for Checkcraft.
Read the guide →Practical workflowPostman collection audit: how many requests have no checks
Open a Postman collection file and see how many requests have no checks, how many only check the status, and whether the file holds tokens. It never leaves your browser.
Read the guide →Practical workflowPostman download for Windows, Linux and Mac: what to do if it will not download
Where to download Postman for Windows, macOS and Linux, whether you need an account, whether a portable build exists and what to check if the installer will not download or start.
Read the guide →Practical workflowPostman not working or not opening: causes and fixes
What to check when Postman will not start, will not let you sign in, does not send requests or has lost team collections: service status, sign-in, Agent, proxy and the free plan.
Read the guide →Practical workflowUnexpected token is not valid JSON: what it means and how to find it
The JSON.parse error by its exact text: the < character, <!DOCTYPE, [object Object], undefined, Unexpected end of JSON input, trailing commas and quotes. How to find the spot in a minute.
Read the guide →Practical workflowUnexpected token <, <!DOCTYPE is not valid JSON: the server returned HTML
Why an HTML page arrives instead of JSON and how to find the cause: a wrong URL and 404, a redirect to the login page, a 502 proxy error or index.html instead of the API.
Read the guide →Practical workflowOnline JSON validator that explains the error
Paste JSON and find out whether it is valid. If not, see the line, the character and the cause: a trailing comma, quotes, a comment, a cut-off response or HTML instead of JSON. Data never leaves your browser.
Read the guide →Practical workflowCompare two JSON documents online: added, missing and changed
Paste two JSON documents and get a list of differences by field path: changed values, changed types and fields present in only one of them. Field order does not matter. Data never leaves your browser.
Read the guide →Practical workflowSoapUI download: where to get it and what to do if it will not start
Where to download free SoapUI Open Source for Windows, macOS and Linux, how it differs from ReadyAPI and what to do when nobody can maintain Groovy-based SOAP checks.
Read the guide →Practical workflowcURL examples: GET and POST requests with JSON on Linux, Windows and PowerShell
Ready-made curl commands: GET with the status code, POST with JSON from a string or a file, the --json option and a Bearer token. How to quote in bash, cmd and PowerShell.
Read the guide →Practical workflowDecode a JWT online: expiry, payload and signature
Paste a JWT to see its header, payload and lifetime: when it was issued, when it expires and who issued it. The token stays in your browser; the signature is not verified.
Read the guide →Practical workflowOpen and view JSON online: tree view and field paths
Open a JSON file or paste text to see it as a tree: nested objects collapse and clicking a field shows its path. The file never leaves your browser.
Read the guide →Practical workflowJSONPath online: test an expression on your JSON
Test a JSONPath expression on your JSON: fields, arrays, slices, recursive descent and filters with conditions. The result lists the values found and their paths.
Read the guide →Practical workflowValidate JSON against a JSON Schema online
Paste a schema and JSON to get a list of violations by field: type, required and extra fields, enum, length, patterns, nested schemas and $ref references. Unsupported keywords are named explicitly.
Read the guide →Practical workflowAPI error 500: server problem or bad request
What 500 Internal Server Error means, how to tell whether your request breaks the server, how 500 differs from 502, 503 and 504, and what to do about “Request failed with status code 500”.
Read the guide →Practical workflowCORS error: why it works in Postman but not in the browser
What “has been blocked by CORS policy” means, why the request passes in Postman and curl but not in a browser, how the OPTIONS preflight works and what to configure on the server.
Read the guide →Practical workflowPostman errors 401, 403, 405 and 415: what they mean and how to fix them
Common Postman status codes: 401 with a missing or expired token, 403 without permissions, 405 because of the method or URL, 415 because of a wrong Content-Type. What to check on the Authorization, Headers and Body tabs.
Read the guide →Practical workflowPostman in Russian: is there a Russian interface
Whether Postman has a Russian language option, whether to install an unofficial translation and how to get around the English interface quickly.
Read the guide →Practical workflowPostman for Linux: install with Snap or the archive, and Astra Linux
How to install Postman on Linux: Snap, which Postman itself recommends, or the tar.gz archive, a menu shortcut and what to consider on Astra Linux and in locked-down environments.
Read the guide →Practical workflowBruno: an API client overview and comparison with Postman
What Bruno is: an open-source API client that keeps collections as files in your repository with no cloud or account. How to move collections from Postman and who Bruno suits.
Read the guide →Practical workflowSwagger Editor online: open and validate an OpenAPI specification
Where to open Swagger Editor, how to paste or load a specification, what the validation errors mean, when to run the editor locally and how to turn a specification into API checks.
Read the guide →Practical workflowLog analysis without programming: where to start
How to analyse application logs without scripts: a question, a time window, an operation ID, grouping errors and comparing with normal behaviour. Commands for files on Linux and Windows and searching in Kibana.
Read the guide →Practical workflowFree public APIs to practise API testing
Practice APIs that work without sign-up: JSONPlaceholder, httpbin, Swagger Petstore, Restful Booker, ReqRes, DummyJSON. What each offers and what to test on it.
Read the guide →Practical workflowHow to validate XML against an XSD: xmllint, PowerShell and common errors
Validate XML against an XSD schema on your own computer: the xmllint command for Linux and macOS, a PowerShell script for Windows with nothing to install, and what typical errors mean.
Read the guide →Practical workflow400 Bad Request in an API: what is wrong with the request
What 400 Bad Request means, how to find the wrong field from the server answer, why a 400 can come from Content-Type, encoding or oversized cookies, and how to check such answers in tests.
Read the guide →Practical workflow401 Unauthorized in an API and Postman: why access is denied
What 401 Unauthorized means, how it differs from 403, why the token does not reach the server, how to check its expiry and what to do when a 401 appears after a redirect.
Read the guide →Practical workflow403 Forbidden: what it means and how to fix it in an API
What 403 Forbidden means, how it differs from 401, the usual causes in an API, where a 403 from nginx comes from and how to test access rights.
Read the guide →Practical workflowFormat JSON online: pretty print, minify and sort keys
Paste JSON to pretty-print it with 2 or 4 spaces or tabs, minify it to one line or sort the keys. Syntax errors are shown with the line and cause. Your data never leaves the browser.
Read the guide →Practical workflowJSON to CSV online: a spreadsheet without uploading the file
Turn a JSON array into a CSV table: nested fields become columns, non-Latin text opens correctly in Excel and you choose the delimiter. The file never leaves your browser.
Read the guide →Practical workflowUnexpected end of JSON input: why the JSON ends early
What “SyntaxError: Unexpected end of JSON input” means, why it happens on an empty 204 or 500 response, how to read a response safely with fetch and how to find where the JSON was cut.
Read the guide →Practical workflowtraceId: what it is and how to find a request in the logs
What a traceId and the traceparent header are, where to get the request identifier, how to find its records in Kibana and why a tester should read the logs when the API answered 200.
Read the guide →Practical workflowPostman variables: environments, collections and passing a token
How Postman variables work: scopes and their precedence, the {{name}} syntax, saving a token from a response with a script, dynamic variables and why a variable is not substituted.
Read the guide →Practical workflowPractice API with bugs: find all 10
A trainer for testers: a practice online-shop API with documentation and ten hidden bugs. Send requests from this page, Postman or curl and check yourself.
Read the guide →No matches. Try JSON, logs or AI, or .