canonical: https://jentic.com/apis/fastgstrefund.com/fastgstrefund # Fast GST Refund preparation APIs The Fast GST Refund preparation API validates records and builds the Statement 3 and Annexure B JSON files a business uploads for a GST export refund claim in India. The validate action is open to everyone and returns each error with its JSON path and a plain-language fix, while the generate action needs a signed-in account that has paid for the specific claim. It also serves a stage-by-stage preparation checklist and lets you re-download or delete a generated file within its 24-hour window. It stops at file preparation: there is no source-system retrieval, eligibility decision, or government submission. ## For AI agents Validate GST export-refund records, then build the Statement 3 and Annexure B JSON files for upload to the Indian GST portal. Returns every validation error with its path and a plain-language fix. ## Scope Does not handle source-system retrieval, eligibility decisions, or government submission. Use for preparing and validating GST refund Statement 3 and Annexure B files only. ## Capabilities - Validate Statement 3 and Annexure B records and get each error with its JSON path and a plain-language fix - Build the Statement 3 JSON file from export invoices, debit notes, and credit notes with their bank realisation rows - Build the Annexure B JSON file with ITC reversal totals and one row per input category and HSN or SAC code - Get a preparation checklist tailored to the refund stage and topic, from eligibility to answering a notice - Re-download or delete a generated refund file within its 24-hour window ## Use cases ### Agent-prepared refund filing through Jentic An AI agent assembles an exporter's invoices and bank realisation rows, runs them through the validate action to catch missing shipping bills or malformed GSTINs, applies the returned fixes, then builds the Statement 3 and Annexure B files ready for the GST portal. Because validation is free and open, the agent can iterate until the records are clean before the account is charged for the generate step. Example prompt: Validate a Statement 3 payload for one GSTIN with two export invoices and their BRC rows, apply any returned fixes, then call the generate action to download the JSON file ### Statement 3 preparation for service exporters Service exporters reconcile export invoices against bank realisation certificates before claiming a refund. The API validates that each BRC or FIRC row is well formed and that documents and receipts tie together, returning errors keyed to the exact field path so a finance tool can surface them inline, then builds the portal-ready Statement 3 file. Example prompt: Validate a Statement 3 payload whose receipts list two BRC rows against three service-export invoices and report any field-level errors ### Annexure B input-tax-credit reconciliation A refund claim needs Annexure B listing eligible input tax credit with reversal totals from GSTR-3B. The API checks that each invoice row carries a valid inward-supply type, HSN or SAC code, and tax split, flags blocked or ineligible credit, and builds the Annexure B JSON file so the claim's ITC section matches the returns. Example prompt: Validate an Annexure B payload with reversal totals and five invoice rows, then build the file once validation passes ### Pre-filing checklist automation Before touching the portal, a preparer wants the records and checks for their current stage. The checklist endpoint takes a stage and a need and returns the records to gather, the checks to run, and the next step, so an assistant can walk a claimant through preparing, uploading, filing, or responding to a deficiency memo. Example prompt: Fetch the checklist for the preparing stage and the statement3 need and list the records to gather ## Key endpoints | Method | Path | Description | | --- | --- | --- | | GET | `/api/generators/statement3` | Statement 3 fields and where each value comes from | | POST | `/api/generators/statement3` | Validate records or build the Statement 3 JSON file | | GET | `/api/generators/annexureb` | Annexure B fields and where each value comes from | | POST | `/api/generators/annexureb` | Validate records or build the Annexure B JSON file | | GET | `/api/checklist` | Get records and checks for a refund stage and topic | | GET | `/api/generator-files/{id}` | Re-download a generated file within 24 hours | | DELETE | `/api/generator-files/{id}` | Delete a stored generated file before it expires | ## Key resources - **Statement 3 generator** — Validate export invoices and bank realisation rows, then build the Statement 3 JSON file - **Annexure B generator** — Validate inward-supply invoices and reversal totals, then build the Annexure B JSON file - **Generated files** — Re-download or delete a created refund file within its 24-hour window - **Preparation checklist** — Records, checks, and the next step for each refund stage and topic ## AI readiness This API is usable in Jentic One now. Its AI-readiness score against Jentic's framework shows where it stands today and where improvements would make it even easier for agents to use. - **Score:** 63 / 100 - **Maturity:** AI-Aware - **Dimensions:** - Foundational Compliance: 100 / 100 - Developer Experience & Jentic Compatibility: 63 / 100 - AI-Readiness & Agent Experience: 54 / 100 - Agent Usability: 94 / 100 - Security: 90 / 100 - AI Discoverability: 29 / 100 - **View full report:** https://jentic.com/apis/fastgstrefund.com/fastgstrefund/scorecard - **How the score is calculated:** https://docs.jentic.com/reference/api-readiness-framework/overview/ - **More about the dimensions:** https://docs.jentic.com/reference/api-readiness-framework/specification/#dimensional-model-overview ### Score it yourself Every API in the directory is allowlisted, so you can re-score it with no key required. - **Score your own API:** https://jentic.com/scorecard.md - **Scoring CLI agent skill:** https://github.com/jentic/jentic-api-scorecard/blob/main/skills/jentic-api-scorecard/SKILL.md ```sh npx @jentic/api-scorecard-cli score ``` ## Why Jentic - **Setup:** Wiring the Fast GST Refund API by hand means handling its OAuth 2.1 authorization-code flow with PKCE, the 402 payment state for unpaid claims, and the validate-then-generate sequence yourself. Through Jentic you install once, import it from the API Directory, store the credential once, and your agent calls it. - **Permission scoping:** You choose which operations your agent may call, so it can validate records and build refund files while the file-delete operation stays out unless you add it. The validate action needs no account at all, so a read-only agent can check entries without any paid scope. - **Credential handling:** Your Fast GST Refund account token is stored once, encrypted, by your own Jentic One instance and injected at execution time. It never enters the agent's prompt, logs, or context. - **Discovery method:** Agents search Jentic by intent such as 'validate a Statement 3 payload' or 'build an Annexure B file', and Jentic returns the matching operation with its input schema so the agent calls the right endpoint without reading the reference docs. ## Related APIs - **TaxJar** — TaxJar automates US sales tax calculation and filing, while Fast GST Refund prepares Indian GST export refund files. - **Codat Accounting** — Codat pulls invoices and tax data from accounting systems that can feed a GST refund claim. - **TaxBandits** — TaxBandits e-files US information returns, a different jurisdiction from Fast GST Refund's Indian GST focus. ## FAQ ### What authentication does the Fast GST Refund API use? It uses OAuth 2.1 authorization-code flow with PKCE per its OpenAPI spec: a client registers, the person signs in with an emailed code, and the token carries the refund:generate scope. The requirements and checklist reads need no credential, while building or downloading a file needs a signed-in account that has paid for that claim. ### Can I validate records before paying with the Fast GST Refund API? Yes. The validate action needs no account and returns every error with its JSON path and a plain-language fix, so you can clean up an export-refund payload for free. Only the generate action, which returns the finished Statement 3 or Annexure B file, requires an account that has paid for the claim. ### What are the rate limits for the Fast GST Refund API? The checklist endpoint is limited to 60 requests per minute per IP and returns a Retry-After header on a 429 response. The OpenAPI spec does not state limits for the generator operations, so check the Fast GST Refund documentation for current limits before running large batches. ### Is there a Fast GST Refund MCP server? You don't need an MCP server to give your agent the Fast GST Refund API. Jentic connects it directly from the API Directory: import it, store your credential once, and your agent calls its validate, generate, and checklist operations on demand. ### Can I limit what my agent is allowed to do with the Fast GST Refund API? Yes. Write a rule that allows the validate and generate operations and the checklist read, and leave the file-delete operation out of the allowed set, so the agent can prepare and download refund files but cannot remove stored ones. Every call it makes is recorded in your Jentic One instance audit log. ### How do I build a refund file with the Fast GST Refund API through Jentic? Search Jentic for 'build a Statement 3 file', add the Fast GST Refund API from the directory, and store your account token once; your agent then validates the payload and calls the generate action to receive the JSON file. To run it on your own infrastructure, install Jentic One from its GitHub repo.