Free Postman alternative in VS Code: which API client to use
Short answer: if you want to send API requests without leaving VS Code, there are three common approaches: a text-file client (such as REST Client), a GUI client with an account and team sync (such as Thunder Client or Postman's own extension), or an all-in-one toolkit (such as DevSnip Pro). Which one is right depends on how you store requests and whether you work in a team. Feature sets and plans change, so check each extension's Marketplace page for current details.
What to look for
- How requests are stored: in plain files you commit (
.,http .), or in a UI with collections?rest - Account and sync: does it need a sign-in or a cloud workspace?
- Environments and variables: switch between local, staging and production without editing requests.
- Protocols: REST only, or GraphQL and WebSocket too.
- Testing: assertions, chaining requests, repeated runs, a CLI for CI.
- Interop: importing existing collections, cURL import and export, OpenAPI, code generation.
The three approaches
Text-file clients (for example REST Client)
You write requests in . files and send them with a click above each request. Requests are plain text, so they live in the repository and show up in code review. Ideal when the team wants API examples versioned next to the code; less suited if you prefer forms and a visual response explorer.
GUI clients with collections and sync (for example Thunder Client, Postman)
Form-based clients with collections and environments, familiar from standalone API tools. They are the natural choice when you already have Postman collections, share workspaces with a team, or need a runner in CI. Some features may need an account or a paid plan.
All-in-one toolkits (for example DevSnip Pro)
DevSnip Pro's REST API Client is a form-based client inside a larger set of developer tools.
What it does, for free and without an account:
- HTTP and GraphQL requests, Bearer, Basic and API-key auth;
- environments with
{{variable}}substitution, collections in folders and history; - cURL import (paste into the URL bar) and export;
- code generation in JavaScript (fetch or Axios), Python, Go, Java and C#;
- the request shapes of OpenAI, Anthropic, Gemini, Azure OpenAI and Ollama for testing LLM APIs.
Paid for with points you earn by using the extension (nothing to buy): WebSocket, an OAuth 2.0 helper, assertions, request chaining, batch performance runs, response comparison and mock servers.
What it does not do: import Postman or Insomnia collections, read . files, run collections from a CLI, gRPC or SOAP, or team workspaces.
Beside the client, the same extension has a database client, JSON and YAML formatters, a JWT decoder, security scans and LLM tools, which suits you if the API client is one of several small tools you reach for during the day.
Quick comparison by need
| If you want… | Consider |
|---|---|
| Requests versioned as plain text in the repo | A .-file client such as REST Client |
| Existing Postman collections, team sync or a CI runner | Postman's extension or Thunder Client |
| A free client with no account, plus a database client, formatting, security and AI tools | DevSnip Pro |
Moving requests over from Postman
DevSnip Pro cannot import a Postman collection. For the requests you use most, use Copy as cURL (Postman's code snippet view, or your browser's network tab) and paste the command into the DevSnip Pro URL bar; the method, headers and body are imported. Save it to a collection and replace hosts and tokens with environment variables.
The other tools around an API
These are in the Backend & API and Security & Auth sections of the DevSnip Pro sidebar:
| Tool | Use it to |
|---|---|
| OpenAPI / Swagger Toolkit | Lint a spec, list endpoints, generate TypeScript types, a fetch client and cURL |
| GraphQL Formatter & Types | Format queries, build request bodies, turn SDL into TypeScript |
| cURL Converter | Turn a cURL command into fetch, Axios, Python, Go and more |
| API Response Inspector | Pretty-print a raw HTTP response with status, headers, paging and caching hints |
| CORS Builder & Debugger | Configure CORS and fix CORS errors |
| API Resource Scaffolder | Generate a validated CRUD API for Express, NestJS, Next.js or Fastify |
| Mock Data Generator | Create seeded fake records as JSON, CSV or SQL |
| JWT Decoder & Signer | Decode, verify and sign test tokens locally |
| Endpoint Security Scan | Check a live endpoint's TLS, HSTS, headers, CSP, CORS and cookies |
Tips that apply to any client
- Keep secrets in environment variables, not in saved requests.
- Save the requests you run more than twice; they become documentation.
- Paste cURL from your browser's network tab instead of retyping requests.
- Look at headers and error responses, not only
200 OK.