GST GSP API Integration Services
e-Invoice · e-Way Bill · GSTR Automation

A GST Suvidha Provider (GSP) is a company authorised by GSTN (Goods and Services Tax Network) to build and operate technology middleware between taxpayers' business systems and the official GST portal. As of 2025, GSTN has authorised a limited set of GSPs in India, including well-known names like Masters India, Tera Software, IRIS Business, Karvy Data, Cygnet Infotech, and others.

GSP API access works as a two-layer model: your business software (ERP, Tally, e-commerce platform, billing system) connects to the GSP's API gateway using OAuth 2.0 authentication and your GSTIN credentials. The GSP then communicates with GSTN on your behalf — handling GSTR filing, e-Invoice generation (IRP), e-Way Bill creation, GSTR-2B reconciliation, and more. You never have direct API access to GSTN; all communication is mediated through the GSP.

Key technical components:

• OTP-based authentication: Each GSP session begins with an OTP sent to the registered mobile/email of the GSTIN.
• Auth token lifecycle: Access tokens are short-lived (6 hours) and must be refreshed without interrupting your workflow.
• Encryption: All payloads transmitted to/from GSP APIs are encrypted using a session-specific key derived from the GSP's public key and your application key.
• API rate limits: GSTN enforces strict rate limits per GSTIN per API endpoint — your integration must handle retry logic with exponential backoff.

PrecisionTech integrates your business software with leading GSPs, handles all authentication and token management, implements payload encryption, and ensures your Tally or ERP data flows to GST returns and e-Invoices automatically.

These are three separate government API ecosystems, each serving a distinct compliance function:

1. GSP API (GSTN Portal APIs)
Used for: GSTR-1 filing, GSTR-3B filing, GSTR-2B pulling, ITC ledger queries, taxpayer profile lookup, return status check. These APIs help you file GST returns programmatically and pull your ITC data directly into your ERP without logging into the GST portal manually.

2. IRP API (Invoice Registration Portal — e-Invoice)
Used for: Generating IRN (Invoice Reference Number) for B2B invoices, printing QR codes on invoices, cancelling IRNs within 24 hours, and pulling e-Invoice details. Mandatory for businesses with annual turnover above ₹5 crore as of August 2023. The IRP APIs are accessible either directly or via GSP.

3. e-Way Bill API (NIC Portal)
Used for: Generating e-Way Bills for goods movement above ₹50,000 value, updating vehicle numbers (Part B), cancelling within 24 hours, and extending validity. These APIs are hosted by NIC (National Informatics Centre) and accessed via a separate GSP connection or directly.

Do you need all three? It depends on your business:

• Manufacturers and distributors with B2B sales above ₹5 crore: All three (GSP + IRP + e-Way Bill)
• Service businesses filing GSTR-1 and GSTR-3B: GSP API only
• Transporters: e-Way Bill API only
• B2B suppliers above threshold: IRP + e-Way Bill, optionally GSP for return filing

PrecisionTech assesses your exact compliance obligations and integrates only what you need — no unnecessary complexity.

Tally Prime has built-in GST compliance features, but its native GST portal connectivity is limited to manual upload of JSON files. GSP API integration with Tally Prime provides full automation — eliminating the manual download-upload cycle entirely.

How PrecisionTech implements Tally-GSP integration:

1. Data extraction: A TDL (Tally Definition Language) script or ODBC/XML connector extracts invoice data from Tally in the format required by the GSP API — GSTIN, invoice number, date, HSN/SAC, tax amounts, party GSTIN, etc.
2. Middleware layer: A lightweight Python/Node.js service running on your server (or cloud VM) receives Tally data, handles GSP authentication (OTP, token refresh, encryption), and submits to the GSP.
3. e-Invoice flow: For B2B invoices requiring IRN — the middleware calls the IRP API, receives the IRN and QR code, and pushes this back into Tally so the printed invoice carries the QR code and IRN automatically.
4. e-Way Bill flow: For goods dispatch — the middleware triggers e-Way Bill generation from the Tally dispatch voucher, receives the EWB number, and stores it against the invoice in Tally.
5. GSTR-2B reconciliation: Automatically pulls your GSTR-2B from the GSP, compares it with your Tally purchase register, and flags mismatches for your accountant.
6. Return filing: Pushes GSTR-1 data from Tally to the GSP for filing — no manual JSON export required.

PrecisionTech has deep expertise in both TDL development and GSP API integration, making us uniquely positioned to deliver end-to-end Tally-GST automation.

GSP API integration is not legally mandatory — you can continue filing GST returns manually through the GST portal. However, for businesses above certain thresholds, specific API-based compliance IS mandatory:

e-Invoice (IRP API) — Mandatory thresholds:

• Annual turnover above ₹500 crore: Mandatory from October 2020
• Above ₹100 crore: Mandatory from January 2021
• Above ₹50 crore: Mandatory from April 2021
• Above ₹20 crore: Mandatory from April 2022
• Above ₹10 crore: Mandatory from October 2022
• Above ₹5 crore: Mandatory from August 2023

If you are above ₹5 crore annual turnover and issuing B2B invoices without e-Invoice, you are non-compliant — your invoices are legally invalid and your buyer cannot claim ITC on them.

e-Way Bill: Mandatory for interstate goods movement above ₹50,000 value regardless of turnover.

Practical reasons to automate even when not mandatory:

• Manual filing takes 4–12 hours per month for a typical SME
• Human errors in JSON export lead to mismatches and ITC rejections
• GSTR-2B reconciliation manually across hundreds of invoices is error-prone
• Banks and large buyers increasingly require IRP-stamped invoices for payment processing

PrecisionTech recommends API integration for any business with more than 50 B2B invoices per month.

GSTR-2B is an auto-generated, static ITC statement available on the 14th of every month showing the Input Tax Credit (ITC) available to you based on invoices filed by your suppliers. It is the legal basis for claiming ITC under Section 16(2)(aa) of the CGST Act, 2017 (as amended).

The reconciliation problem: Your GSTR-2B shows ITC available from suppliers. Your purchase register in Tally/ERP shows what you actually received and recorded. These two never match perfectly because:

• Suppliers file GSTR-1 late — their invoices don't appear in your GSTR-2B for that month
• Suppliers file with wrong GSTIN, date, or invoice number
• You recorded the invoice in a different month than the supplier filed
• GST rate differences — you recorded 18% but supplier filed 12%
• Credit notes and debit notes don't match

The financial impact: Unclaimed ITC = cash flow loss. Many Indian businesses lose 2–8% of their ITC every year simply because they don't reconcile properly and miss the window to follow up with suppliers.

How automated reconciliation works:

1. GSP API pulls your GSTR-2B data every month automatically on the 15th
2. Middleware compares it with your Tally purchase register line by line
3. Mismatches are categorised: supplier not filed, amount mismatch, GSTIN mismatch, invoice number mismatch
4. Report is sent to your accountant with the list of suppliers to follow up with
5. After supplier correction and re-filing, re-reconciliation runs automatically

PrecisionTech clients recovering ₹2–15 lakh per year in previously unclaimed ITC after implementing automated GSTR-2B reconciliation is common. The ROI on integration typically exceeds 10x in the first year alone.

The e-Invoice process under GST requires eligible businesses to register every B2B invoice with the Invoice Registration Portal (IRP) before (or at the time of) issuing it to the buyer. Here is the complete flow:

Step-by-step IRN generation process:

1. Invoice creation: You raise an invoice in Tally/ERP with all mandatory fields — GSTIN of supplier, GSTIN of buyer, invoice number, date, HSN/SAC codes, item descriptions, quantities, rates, GST amounts, POS (Place of Supply).
2. JSON generation: The invoice data is formatted into the GSTN e-Invoice JSON schema (currently schema version 1.1).
3. IRP submission: The JSON is submitted to IRP via API. IRP validates the data, checks for duplicates, and generates a unique IRN (Invoice Reference Number) — a 64-character hash.
4. QR code: IRP generates a signed QR code containing the IRN, GSTIN of buyer and seller, invoice number, date, total value, and number of line items. This QR code is digitally signed with NIC's private key.
5. IRN storage: The IRN and QR code are pushed back into your Tally/ERP and printed on the invoice PDF automatically.

If you miss generating IRN:

• The invoice is not valid under GST law — your buyer cannot claim ITC on it
• IRP allows cancellation and re-generation only within 24 hours of the original IRN timestamp
• After 24 hours, the IRN cannot be cancelled — if the invoice details are wrong, you must issue a credit note and a new invoice
• GSTN can impose penalties under Section 122 of the CGST Act
• Repeated non-compliance can trigger scrutiny, audit, and ITC reversal demands on your buyers

Automated e-Invoice integration through PrecisionTech ensures IRN is generated at the moment of invoice save in Tally — eliminating manual steps and the 24-hour cancellation risk entirely.

Every e-Invoice submitted to IRP must include a valid HSN (Harmonised System of Nomenclature) code for goods or SAC (Services Accounting Code) for services, along with the correct GST rate for that HSN/SAC. IRP validates both at the time of submission — invalid HSN or wrong GST rate results in API rejection.

HSN code requirements (as of 2024):

• Turnover above ₹5 crore: 6-digit HSN mandatory
• Turnover ₹1.5–5 crore: 4-digit HSN mandatory
• Turnover below ₹1.5 crore: 2-digit HSN for goods (optional for services)
• Exporters: 8-digit HSN recommended for customs alignment

Common HSN/GST rate errors that cause rejections:

• Using a 4-digit HSN when 6-digit is required (e.g., 8471 instead of 847130)
• HSN not matching GST rate in the tariff (e.g., filing 12% GST on an HSN that attracts 18%)
• Using discontinued or merged HSN codes (tariff is updated periodically by CBIC)
• Mixing goods HSN with services SAC on the same invoice line
• Nil-rated, exempt, and zero-rated items needing specific handling in the JSON schema

Financial consequences of wrong HSN:

• ITC reversal demands on your buyers if GST rate is understated
• Excess tax payment if GST rate is overstated (hard to recover)
• Show cause notices under Section 122 for systematic misclassification
• Export refund delays if HSN does not match ICEGATE records

PrecisionTech builds an HSN master validation layer into every GSP API integration — all HSN codes and rates are validated against the current CBIC tariff before submission to IRP, preventing rejections and compliance risks.

Yes. GSP API integration is ERP-agnostic — the GSP API endpoints are standard REST APIs that any system can call. PrecisionTech has implemented GSP/IRP/e-Way Bill integration with a wide range of business software:

ERP and accounting software we integrate:

• Tally Prime / Tally ERP 9: Via TDL customisation + middleware service
• SAP Business One / SAP ECC / SAP S/4HANA: Via ABAP add-on or middleware API bridge
• Oracle NetSuite: Via SuiteScript 2.x + REST connector
• Microsoft Dynamics 365 Business Central: Via AL extension + API connector
• Zoho Books / Zoho ERP: Via Zoho Flow + custom function
• QuickBooks: Via webhook + middleware
• Custom ERP / in-house billing software: Via REST API wrapper that your development team calls
• E-commerce platforms (WooCommerce, Shopify, Magento): Via plugin + middleware for B2B invoice automation

Integration architecture options:

1. On-premise middleware: A service installed on your server that polls your ERP for new invoices and submits to GSP. Best for high-volume, latency-sensitive environments.
2. Cloud middleware (SaaS): A hosted API service that your ERP calls via webhook. Best for cloud ERP customers.
3. Scheduled batch processing: Invoices are collected hourly/daily and submitted in batches. Best for lower-volume operations.
4. Real-time event-driven: IRN is generated at the moment of invoice save — before the PDF is generated. Best for enterprises where the printed invoice must carry the IRN.

PrecisionTech designs the integration architecture based on your ERP, invoice volume, latency requirements, and IT infrastructure.

The e-Way Bill is a mandatory electronic document for movement of goods worth more than ₹50,000 in value (with certain state-specific thresholds). It is generated on the NIC e-Way Bill portal and must accompany the consignment. The e-Way Bill API allows automated generation, update, and cancellation without logging into the portal.

e-Way Bill API capabilities:

• GENEWAYBILL: Generate a new e-Way Bill with Part A (invoice details) and Part B (vehicle/transporter details)
• UPDATEVEHICLE: Update transporter or vehicle number in Part B after generation
• CANCELEWB: Cancel within 24 hours if goods not dispatched
• EXTENDVALIDITY: Extend EWB validity if goods are in transit (requires transit document)
• GETEWB: Retrieve EWB details by EWB number or by doc number
• GETEWBLIST: List EWBs generated for a GSTIN in a date range

How automated dispatch integration works with PrecisionTech:

1. Dispatch team creates a delivery challan or invoice in Tally/ERP with transporter details and vehicle number
2. Middleware detects the new document, checks the value (if above ₹50,000 and goods category requires EWB)
3. e-Way Bill is auto-generated via API and the EWB number is returned within 2–3 seconds
4. EWB number is printed on the delivery challan/invoice automatically
5. Dispatch gate can verify the EWB number before releasing the vehicle
6. If vehicle changes, dispatcher updates Part B via the same integration — no manual portal login required

Special scenarios handled:

• Multi-vehicle consolidated EWB (for shipments split across multiple trucks)
• Bill-to Ship-to triangular transactions (three-party EWB)
• Sub-supply and job work EWB scenarios
• Inward EWB acceptance and rejection workflows

Input Tax Credit (ITC) is the single largest GST-related cash flow lever for Indian businesses. Systematic GSP API integration directly impacts how much ITC you claim and how quickly it reflects in your electronic credit ledger.

ITC maximisation through GSP integration:

1. Real-time GSTR-2B matching: Instead of waiting until the 14th of the month, GSP API allows you to pull provisional ITC data from GSTR-2A (filed by suppliers) daily. You can see which suppliers have filed and which haven't — allowing you to chase non-compliant vendors before the GSTR-2B locks.

2. Supplier compliance scoring: Your integration can automatically flag suppliers with a history of late filing, ITC mismatch, or non-compliance. This data feeds your vendor master in Tally — helping your purchase team make informed decisions about which suppliers to prefer.

3. ITC reversal prevention: Section 16(2)(aa) requires that your supplier must have filed GSTR-1 for your ITC to be valid. Automated monthly reconciliation ensures you identify mismatches early and reverse only what is legally required — avoiding over-reversal.

4. Blocked credit identification: Certain credits are ineligible under Section 17(5) — personal consumption, motor vehicles (with exceptions), food and beverages, etc. An integration layer can flag potentially blocked credits in your purchase data before you accidentally claim them.

Working capital impact:

• Faster ITC claim cycle: Monthly instead of quarterly catch-up
• Reduced interest cost: ₹1 lakh of additional ITC claimed monthly = ₹12,000/year in working capital benefit at 12% cost of funds
• Cleaner books: Automatic posting of ITC amounts to the correct Tally ledgers reduces period-end closing time

PrecisionTech clients typically see 15–25% improvement in claimed ITC in the first year post-integration.

GSP API integration handles sensitive financial and business data — GSTIN credentials, invoice details, party names, bank account information in some flows. GSTN enforces specific security requirements on GSPs and their downstream integrations.

GSTN-mandated security requirements:

• Payload encryption: All API payloads must be encrypted using a session key derived from GSTN's public key and your application's private key (AES-256 encryption)
• OTP authentication: Each new session requires OTP validation from the registered GSTIN mobile/email
• Token expiry: Auth tokens expire in 6 hours — integration must handle silent refresh
• IP whitelisting: Some GSPs require whitelisting of server IPs making API calls
• TLS 1.2+: All API communication must use TLS 1.2 or higher
• Audit logging: All API calls must be logged with timestamp, GSTIN, endpoint, and response code

PrecisionTech's security implementation:

• Credentials are stored in encrypted vaults — never in plain text config files
• API keys and GSP credentials are stored using AES-256 at-rest encryption
• Middleware services run in isolated containers with minimal privilege
• All API logs are stored with 24-month retention for audit purposes
• GSTIN OTPs are handled through secure in-memory processing — not logged or stored
• Network segmentation: middleware servers are on private subnets, not directly accessible from the internet
• Regular security audits and dependency updates included in AMC

PrecisionTech builds every GSP integration to be ISO 27001-aligned in its security architecture — protecting your GSTIN credentials and invoice data at every layer.

Project timeline and cost depend on the scope of integration — specifically which APIs you need (GSP for returns, IRP for e-Invoice, e-Way Bill), your ERP, invoice volume, and existing IT infrastructure.

Typical timelines:

• e-Invoice only (IRP API) with Tally: 5–10 business days from requirements sign-off to UAT
• e-Invoice + e-Way Bill with Tally: 10–15 business days
• Full GSP integration (returns + e-Invoice + e-Way Bill + GSTR-2B reconciliation): 15–25 business days
• Custom ERP integration: 3–8 weeks depending on ERP complexity and API availability

What is included in the project:

• Requirements workshop and compliance assessment (which APIs are mandatory for your business)
• GSP selection and onboarding assistance
• Middleware development and configuration
• TDL customisation for Tally (if applicable)
• Test environment setup and UAT with sample invoices
• Go-live support and parallel run for 2 weeks
• Staff training — accounts team and dispatch team
• Full documentation
• Post-go-live support for 30 days

Ongoing AMC: Annual Maintenance Contract covering GSP API schema updates (GSTN periodically updates e-Invoice and GSTR schemas), GSP credential renewal support, and monthly health monitoring.

Contact PrecisionTech via our enquiry form for a fixed-price quote specific to your ERP, invoice volume, and scope.

GSTN updates the e-Invoice JSON schema, IRP API specifications, and GSP API endpoints periodically. Historically, significant updates have happened 3–5 times per year — including the addition of new mandatory fields, changes to HSN validation rules, updates to the QR code content specification, and changes to IRP endpoint URLs.

Notable past updates that broke integrations:

• Schema version 1.03 → 1.1 in 2021: Added new mandatory fields for supply type, export type, and shipping details
• IRP multi-portal rollout in 2023: IRP moved from a single portal to 5 portals (IRIS, Clear, Cygnet, EY, others) — requiring fallback logic
• HSN validation tightening in 2022: 6-digit HSN became mandatory for above-5cr turnover, breaking integrations using 4-digit HSN
• GSTR-2B structural changes in 2022–23: New fields added requiring reconciliation logic updates

How PrecisionTech keeps you compliant:

• GSTN sandbox monitoring: We monitor the GSTN sandbox environment where GSTN releases updates before production — typically 30–60 days in advance
• Automated schema validation: Our middleware validates against the current schema version before every API call — catching issues before they reach IRP
• AMC update coverage: All schema and API updates are covered under the Annual Maintenance Contract — you do not pay separately for mandatory compliance updates
• Proactive notifications: We alert you 2 weeks before any GSTN update that affects your integration

Choosing PrecisionTech for GSP API integration means you have a long-term compliance partner — not just a one-time implementation vendor.

Yes. Multi-GSTIN integration is one of the most common requirements for business groups, franchise networks, and companies with state-wise GST registrations.

Multi-GSTIN integration scenarios:

• Branch accounting: A company with GSTIN in Maharashtra, Karnataka, Tamil Nadu, and Delhi — each GSTIN files independently but all data flows through a single Tally installation or central ERP
• Multi-entity groups: A business group with 3 legal entities each having their own GSTIN — central finance team manages all compliance from one dashboard
• Franchise networks: Franchisor generates consolidated reports while each franchisee GSTIN files independently
• Job work / principal-agent: Multiple GSTINs in a principal-to-job-worker-to-principal flow with ITC-04 compliance

Technical implementation for multi-GSTIN:

• Each GSTIN has independent GSP authentication credentials — OTP and token management is per-GSTIN
• Middleware maintains separate session pools for each GSTIN with independent token refresh cycles
• Tally Company-to-GSTIN mapping ensures invoices from the correct Company file are submitted to the correct GSTIN
• Consolidated reconciliation dashboard shows ITC status across all GSTINs in one view
• GSTN enforces per-GSTIN rate limits — our middleware distributes API calls to avoid throttling

PrecisionTech has implemented multi-GSTIN integrations for groups with 2 to 28 GSTINs. We design the architecture to scale as your group adds new registrations.

GSTR-1 is the monthly (or quarterly under QRMP) return showing outward supplies — B2B invoices, B2C summaries, exports, credit notes, and debit notes. GSTR-3B is the summary return where you pay tax. GSTN cross-references these two returns — mismatches between GSTR-1 and GSTR-3B trigger automated scrutiny notices (DRC-01A, DRC-01B).

How GSP API integration eliminates GSTR-1 vs GSTR-3B mismatches:

1. Single source of truth: All B2B invoices in Tally/ERP that generated an IRN are automatically included in GSTR-1 via GSP API — no manual JSON preparation, no omissions
2. Auto-population from e-Invoice: As of October 2020, all IRN-generated invoices are auto-populated in GSTR-1. When your integration generates IRN, your GSTR-1 is effectively filed simultaneously for those invoices
3. Credit note and debit note tracking: The same middleware that handles IRN generation also tracks credit notes and ensures they appear in GSTR-1 Table 9A/9B
4. B2C aggregation: The middleware aggregates B2C invoices by state for GSTR-1 Table 7 without manual calculation
5. Tax amount consistency: Since the same invoice data from Tally populates both the IRN/e-Invoice and the GSTR-1 JSON, the tax amounts in GSTR-1 and GSTR-3B are always consistent — eliminating the most common source of mismatches

Reconciliation before filing: PrecisionTech's integration generates a pre-filing reconciliation report comparing: total taxable value in Tally, total IRNs generated, total in GSTR-1, and proposed GSTR-3B payment — flagging any difference before you file.

Yes — but each category has specific handling requirements in the API schema and reconciliation logic.

Exporters (IGST zero-rated / LUT):

• e-Invoice for exports includes Export Type (EXPWOP for export without payment, EXPWP for export with IGST payment), shipping bill number, port code, and foreign currency details
• GSTR-1 Table 6A (exports) and refund claim reconciliation is automated
• Integration with ICEGATE for shipping bill data matching to GST portal is available

SEZ supplies:

• Supply Type in e-Invoice must be SEZWOP or SEZWP — auto-detected from buyer GSTIN type
• LUT/Bond number is included in the e-Invoice schema for SEZ supplies

Reverse Charge Mechanism (RCM):

• Purchases attracting RCM (legal services, GTA, import of services, etc.) are flagged in purchase data
• RCM liability is auto-calculated and included in GSTR-3B Table 3.1(d) in the pre-filing report
• ITC on RCM (available in the same period under Section 38) is separately tracked and claimed

Composition dealers:

• Composition dealers are not eligible for e-Invoice and cannot generate IRN — this restriction is enforced by the middleware
• CMP-08 (quarterly payment statement) preparation from Tally data via GSP is supported

Input Service Distributors (ISD):

• ISD credit distribution across GSTINs is tracked and reported via GSP for GSTR-6 compliance

PrecisionTech's compliance assessment at project start identifies your specific GST category requirements and configures the integration accordingly.

The QRMP (Quarterly Return Monthly Payment) scheme allows taxpayers with annual turnover up to ₹5 crore to file GSTR-1 and GSTR-3B quarterly instead of monthly — but pay GST monthly using Form PMT-06.

How QRMP changes the integration logic:

• IFF (Invoice Furnishing Facility): QRMP dealers can optionally upload B2B invoices for months 1 and 2 of the quarter using IFF — so their buyers can see ITC in GSTR-2B without waiting for the quarterly GSTR-1. Our integration supports IFF upload via GSP API.
• Quarterly GSTR-1 submission: At the end of Q1, Q2, Q3, Q4 — the full GSTR-1 is submitted via GSP. Our system batches invoices for the quarter and submits in one operation.
• Monthly PMT-06 calculation: The integration calculates your monthly tax liability (using the 35% of previous quarter's tax or self-assessment method) and prepares the PMT-06 data for your approval before online payment.
• GSTR-2B timing: Under QRMP, GSTR-2B is generated quarterly for Q1 and Q2 month invoices, and monthly for M3 invoices. Our reconciliation module handles this split correctly.

Switching between monthly and QRMP: GSTN allows switching once per quarter. Our integration detects your current filing frequency via GSP API and adapts automatically — no manual reconfiguration required when you switch.

This adaptive approach means PrecisionTech's integration remains correct regardless of your filing frequency choice for each year.

GSP and GSTN APIs are government infrastructure — they experience higher downtime and rate limiting than commercial APIs. Building a resilient integration requires anticipating and handling a specific set of failure modes.

Common failure reasons and how we handle them:

• GSTN portal maintenance windows: GSTN has scheduled maintenance on Sunday 11 PM–1 AM IST. Our integration queues invoices generated during this window and auto-submits when the API comes back online.
• Rate limiting (error code 400/429): GSTN limits API calls per GSTIN per minute. Our middleware uses a token bucket algorithm to distribute calls within rate limits — never exceeding the threshold.
• Auth token expiry: Tokens expire in 6 hours. We implement proactive token refresh 15 minutes before expiry — preventing mid-session authentication failures.
• OTP timeout: OTPs expire in 10 minutes. For automated systems, we implement a secondary flow where OTP is entered once and the resulting long-lived refresh token is used for subsequent sessions.
• Schema validation failures (error 2145, 2150, 2160 etc.): IRP returns specific error codes for schema violations. Our middleware maps each error code to a human-readable message and alerts the accounts team with the specific field causing the rejection.
• Network timeouts: Government API servers have variable response times. All API calls use timeout handling with 3 retry attempts and exponential backoff before marking an invoice as failed.
• IRP unavailability: With 5 live IRPs, our middleware implements automatic fallback — if primary IRP fails, it retries on the secondary IRP within 30 seconds.

Monitoring and alerting: PrecisionTech's integrations include a health monitoring dashboard showing success rate, pending queue size, last successful sync time, and error trends — with email/WhatsApp alerts to the designated admin if error rate exceeds 5%.

High-volume invoice environments require a fundamentally different integration architecture than low-volume setups. At 1,000+ invoices per day, the GSTN rate limits, IRP API throughput, and system resilience requirements are significantly more demanding.

Architecture for high-volume integrations:

• Message queue: Invoices from Tally/ERP are pushed to a message queue (RabbitMQ or Redis Queue) rather than being submitted directly. This decouples invoice creation from API submission and provides buffering during GSTN slow periods.
• Worker pool: Multiple worker processes consume from the queue simultaneously — each managing their own GSP auth session. Worker count scales with invoice volume.
• Batch submission: For GSTR-1 bulk upload scenarios, our middleware batches invoices into the maximum payload size allowed by GSTN (typically 1,000 invoices per API call) to minimise API call count.
• Multi-GSTIN load balancing: For businesses with multiple GSTINs, invoice submissions are distributed across GSTINs to stay within per-GSTIN rate limits.
• Database persistence: Every invoice submission attempt is persisted to a local database with status (pending, submitted, IRN received, failed). Failed invoices are automatically retried in the next cycle.
• Priority queue: High-priority invoices (large value, export, time-sensitive EWB) are processed first — other invoices wait in queue without blocking critical submissions.

Performance benchmarks PrecisionTech achieves:

• IRN generation: 2–4 seconds per invoice (end-to-end including Tally extraction)
• Batch mode: 500 invoices per hour sustained throughput
• System uptime: 99.5%+ (including GSTN downtime handling)

Contact us for high-volume integration architecture assessment and quote.

GSP API integration is not a set-and-forget implementation. GSTN regularly updates APIs, GSPs update their SDKs, and your business evolves — new GST categories, new document types, new state registrations. PrecisionTech provides structured post-implementation support through our Annual Maintenance Contract (AMC).

AMC coverage includes:

• Schema and API updates: All mandatory GSTN schema changes (e-Invoice, e-Way Bill, GSTR schema updates) are implemented within 30 days of GSTN release — no additional charge
• GSP credential renewal: Annual GSP API key renewal, OTP re-authentication support
• Monthly health report: Success rate, error analysis, ITC reconciliation summary, and recommendations
• Error resolution SLA: Critical integration failures (IRN not being generated) — 4-hour response, 24-hour resolution. Non-critical errors (reconciliation mismatch in report) — 48-hour response
• Tally version upgrades: When Tally releases a major update affecting TDL compatibility, we update the TDL scripts within 7 business days
• New GSTIN addition: Adding a new state registration to your integration — covered under AMC (one GSTIN per year; additional at nominal charge)
• Helpdesk: Dedicated helpdesk ticket system with 8-hour response during business hours for non-critical queries

Compliance watch service: Our team monitors GSTN announcements, CBIC notifications, and GSP partner communications — alerting you to upcoming changes that affect your integration before they go live. This prevents compliance disruption from unannounced API changes.

Getting started is straightforward. PrecisionTech follows a structured onboarding process to ensure we scope the integration correctly before writing a single line of code.

Information we need from you (at discovery stage):

1. Business details: Legal entity name, PAN, all GSTINs (states and registration types — regular, composition, SEZ unit, etc.)
2. Annual turnover: To determine mandatory e-Invoice and QRMP applicability
3. Invoice types: B2B, B2C, export with LUT, export with IGST, SEZ, job work, credit notes, debit notes
4. Monthly invoice volume: Approximate count of B2B invoices per month per GSTIN
5. ERP/accounting software: Tally Prime (which version), or other ERP with version details
6. Current filing method: Manual portal, existing GSP (which one), third-party CA-managed
7. IT infrastructure: On-premise server, cloud VPS, or fully cloud ERP
8. e-Way Bill requirement: Whether goods are moved and above ₹50,000 per consignment
9. Special requirements: RCM categories, ISD, job work (ITC-04), ICEGATE integration for exporters

Next steps:

1. Submit your enquiry via our contact page — include your GSTIN count and ERP name
2. Discovery call (30–45 minutes) to assess your compliance obligations and define scope
3. Written proposal with fixed-price quote and implementation timeline
4. Agreement and advance — work begins within 3 business days

PrecisionTech does not require any GSTIN credentials or sensitive information at the enquiry stage. All credential handling is done in a secure environment after agreement is signed.