What is SPEI?
SPEI (Sistema de Pagos Electrónicos Interbancarios) is the real-time gross settlement system for interbank transfers in Mexican pesos. Operational since 2004 and running 24/7 since 2015, it settles in cycles of roughly every two seconds. In 2025 it processed over 7,000 million transfers, with peaks above 200 operations per second, across just over 80 direct participants connected over dedicated links with cryptographic message signing, never the public internet. Any institution operating in Mexico, bank, sofipo, fintech, IFPE, that needs to move MXN between accounts in real time integrates with SPEI.
What is InterPago?
InterPago is the integration layer between your institution’s core banking system and the interbank payment systems. We cover the full cycle: message handling, digital signature, balance management, electronic receipts, and reconciliation. The platform is delivered production-ready and connects to your core without requiring you to rewrite it.
We build on the official specification, not on third-party interpretations. Every component is modular, observable, and audit-ready from day one.
Problems we solve
Mid-day certificate rotation
A certificate expiring during the operating day creates a queue and rejections. We implement overlapping rotation with preload, with no traffic interruption.
Balance race conditions
Peak loads (payroll, end-of-day) can cause projected-balance inconsistencies. Per-shard processing and atomic reservations eliminate the condition.
Receipts out of sync on reversals
Reversing an operation when the receipt was already issued requires careful state handling. Our state engine guarantees consistency between payment, reversal, and receipt.
Late acknowledgments and double charges
An ack outside the window can trigger retry and double charge. Idempotency by tracking key plus persistent dedup eliminates the risk.
Post-deploy payment-flow simulation
Every deployment is validated against the simulator before touching production, synthetic end-to-end payments, and only promotes if all flows pass.
One-click switch between primary and backup
Failover and failback between primary and backup channel from a single button on the operations dashboard, no manual scripts, no cross-team coordination.
Reconciliation with integrated external systems
Cross-reconciliation across the various systems integrated with InterPago, a single dashboard shows breaks by system, counterparty, or transaction type.
Main features
The platform is designed for high volume, high availability, and traceability, these are the architectural components your team will encounter in every implementation.
Authentication & Authorisation
Corporate single sign-on with your identity provider, service identity via mutually authenticated encrypted connections, role-based permissions, and identity propagation across the entire processing chain.
Security & Key Custody
Encryption at rest and in transit. Private keys and secrets protected by hardware, never exposed on disk. Automated secret rotation.
Immutable Logs & Traceability
Immutable logs, structured events, and end-to-end trace per transaction, with full tracing and metrics across the platform.
Reporting & Reconciliation
Pre-built operational and regulatory reports. Multi-source reconciliation engine that identifies breaks by counterparty and transaction type.
Recovery & Resilience
Automated failover, journal replay, idempotent retries. Documented and measurable recovery time objectives, with a zero data loss design.
Multiple Endpoints & Integrations
Simultaneous connection to multiple cores, counterparties, and regulators. Reusable adapters, no bespoke code per new destination.
Message Transformations
Protocol mapping (ISO 20022, legacy and custom formats), schema evolution, and lossless normalisation between formats.
Configurable Validations
Schema, business-rule, compliance, and counterparty validations, all modifiable without touching code.
Circuit Breakers, Throttling & Backpressure
High-volume resilience patterns, circuit breakers per channel and counterparty, adaptive throttling, backpressure to prevent cascading failures.
Dynamic Workflow Orchestrator
Orchestration of payments, validations, retries, and compensations defined as a flow, modifiable hot, no redeploy, with visibility into every step.
Customisable Rule Engine
Business rules configurable by your team: account validation, per-counterparty limits, cut-offs, routing. Production changes without touching code.
Modular Architecture for Distribution
Components independently deployable across data centres or cloud regions, with cross-site replication and consistency for high availability and fault isolation.
Real-Time Analytics
Automated detection of operational anomalies, rising returns/rejections, throughput drop, latency degradation, counterparty pattern deviation. Actionable alerts, not just dashboards.
Compliance & controls
Every component is designed to pass regulatory inspections and internal audits, not as an add-on, but as a core part of the platform.
Per-Transaction Trace and Audit
Immutable log of every operation, structured events, and end-to-end trace, ready to present to auditors.
Regulator-Aligned Retention Policy
Immutable retention per regulator-mandated periods, with automated lifecycle to cold storage.
Maker-Checker
Dual human validation on sensitive operations: operator initiates and reviewer approves before execution.
Dual Key Control
Dual custody of cryptographic keys and critical secrets, no individual has exclusive access.
Secure Sessions and Segregation of Duties
Authenticated sessions with expiry, role-based permissions with clear boundaries between development, operations, treasury, and compliance.
Digital Signature on Every Message
Cryptographic signature on every outbound and inbound message; verification mandatory before any processing.
Restricted Personal Data Access
Personal data masked by default in logs, dashboards, and reports; full access only to authorised roles.
Sanctions and Watch-List Integrations
Pre-built hooks for international watch lists, internal lists, and specialist provider lists, configurable update cadence.
Regulatory Reports on Official Cadence
Automated generation in mandatory format and cadence; direct submission to official platforms.
Incident Reporting, Review and Submissions
Reporting templates, a structured post-incident review process, and on-time submissions per regulatory service commitments.
Regular Business-Continuity Drills
Periodic contingency drills against the simulator, with evidence of results ready for audit.
Frequently asked questions
What is SPEI?
SPEI (Sistema de Pagos Electrónicos Interbancarios) is the Bank of Mexico's real-time gross settlement system for interbank transfers in pesos. It runs 24/7 and processes millions of operations per day across banks, sofipos, fintechs and IFPEs.
Does SPEI operate 24 hours a day?
Yes. SPEI settles in real time 365 days a year, including weekends and holidays. That makes continuous availability and peak-load handling (payroll, period-end) critical requirements of the integration.
How long does a SPEI transfer take?
Settlement is effectively immediate, seconds end to end under normal operation. The acknowledgement returns to the originator to confirm settlement and issue the electronic receipt (CEP).
What does an institution need to integrate with SPEI?
A certified Banxico connection, message handling, digital signature and certificate custody, real-time balance projection, reconciliation and regulatory reporting. InterPago delivers that full lifecycle production-ready, built on the official specification.
How is SPEI different from SPID?
SPEI moves pesos (MXN) and runs 24/7 at very high volume. SPID moves dollars (USD) between Mexican accounts Monday-Friday 08:00-17:00. Many institutions integrate both on the same architecture.
See also our guides: SPEI connection requirements and process, direct vs indirect participant and COA, POA and ASA contingency.