# iso8583sim

> Parse, build, validate and simulate ISO 8583 payment messages in Python.

- [iso8583sim](https://iso8583sim.com/docs/index.md): Parse, build, validate and simulate ISO 8583 payment messages in Python.
- [Installation](https://iso8583sim.com/docs/getting-started/installation.md): Install iso8583sim from PyPI:
- [Quick Start](https://iso8583sim.com/docs/getting-started/quickstart.md): This guide will get you parsing and building ISO 8583 messages in under 5 minutes.
- [ISO 8583 Concepts](https://iso8583sim.com/docs/getting-started/concepts.md): ISO 8583 is the international standard for financial transaction card-originated messages.
- [Upgrading](https://iso8583sim.com/docs/getting-started/upgrading.md): The string-based API (ISO8583Parser.parse, ISO8583Builder.build, ISO8583Validator) has not changed since 1.0.
- [Core Module](https://iso8583sim.com/docs/core/index.md): The core module provides all ISO 8583 message handling functionality.
- [Types & Fields](https://iso8583sim.com/docs/core/types.md): The types module defines all data types, enums, and field definitions used throughout iso8583sim.
- [Parser](https://iso8583sim.com/docs/core/parser.md): The ISO8583Parser class converts raw ISO 8583 message strings into structured ISO8583Message objects.
- [Builder](https://iso8583sim.com/docs/core/builder.md): The ISO8583Builder class constructs raw ISO 8583 message strings from ISO8583Message objects.
- [Validator](https://iso8583sim.com/docs/core/validator.md): The ISO8583Validator class validates ISO 8583 messages for structure and content correctness.
- [EMV Data](https://iso8583sim.com/docs/core/emv.md): The EMV module handles Field 55 (ICC Data) which contains chip card data in TLV (Tag-Length-Value) format.
- [PIN Blocks and MACs](https://iso8583sim.com/docs/core/security.md): The iso8583sim.security module builds and checks the two security fields most test harnesses need: PIN blocks for field 52 and message authentication codes (MACs) for fields 64 and 128.
- [Version Conversion](https://iso8583sim.com/docs/core/convert.md): convert_message converts a message between the 1987, 1993 and 2003 versions of ISO 8583.
- [Wire Formats](https://iso8583sim.com/docs/core/wire.md): The rest of iso8583sim works with messages as strings: an ASCII MTI, a hex bitmap, and binary fields as hex.
- [Object Pool](https://iso8583sim.com/docs/core/pool.md): The MessagePool class provides object pooling for high-throughput scenarios, reducing memory allocation overhead.
- [Card Networks](https://iso8583sim.com/docs/networks/index.md): iso8583sim supports multiple card networks with network-specific field definitions and validation rules.
- [VISA](https://iso8583sim.com/docs/networks/visa.md): VISA-specific field definitions and requirements for iso8583sim.
- [Mastercard](https://iso8583sim.com/docs/networks/mastercard.md): Mastercard-specific field definitions and requirements for iso8583sim.
- [Other Networks](https://iso8583sim.com/docs/networks/others.md): Support for American Express, Discover, JCB, and UnionPay.
- [CLI Reference](https://iso8583sim.com/docs/cli/index.md): iso8583sim provides a command-line interface for parsing, building, and validating ISO 8583 messages.
- [Networking](https://iso8583sim.com/docs/net/index.md): iso8583sim can talk to real hosts over TCP, and can stand in for one.
- [REST API](https://iso8583sim.com/docs/web/index.md): iso8583sim includes a REST API built with FastAPI, for tools and services that aren't written in Python.
- [MCP Server](https://iso8583sim.com/docs/mcp-server/index.md): iso8583sim includes an MCP (Model Context Protocol) server.
- [LLM Features](https://iso8583sim.com/docs/llm/index.md): iso8583sim includes AI-powered features for message explanation and generation using large language models.
- [LLM Providers](https://iso8583sim.com/docs/llm/providers.md): iso8583sim supports multiple LLM providers with a unified interface.
- [Message Explainer](https://iso8583sim.com/docs/llm/explainer.md): The MessageExplainer class uses LLMs to explain ISO 8583 messages in plain English.
- [Message Generator](https://iso8583sim.com/docs/llm/generator.md): The MessageGenerator class uses LLMs to create ISO 8583 messages from natural language descriptions.
- [Architecture Overview](https://iso8583sim.com/docs/architecture/overview.md): iso8583sim is designed with a focus on performance, extensibility, and ease of use.
- [Message Flow](https://iso8583sim.com/docs/architecture/message-flow.md): This document describes how ISO 8583 messages flow through iso8583sim.
- [Module Structure](https://iso8583sim.com/docs/architecture/module-structure.md): This document describes the package organization and module responsibilities.
- [Performance Optimization Guide](https://iso8583sim.com/docs/performance.md): This document describes the performance optimizations implemented in iso8583sim v0.3.0 and how to leverage them for high-throughput message processing.
- [Troubleshooting](https://iso8583sim.com/docs/troubleshooting.md): Common issues and solutions when using iso8583sim.
- [Types](https://iso8583sim.com/docs/api/core/types.md): iso8583sim.core.types
- [Parser](https://iso8583sim.com/docs/api/core/parser.md): iso8583sim.core.parser
- [Builder](https://iso8583sim.com/docs/api/core/builder.md): iso8583sim.core.builder
- [Validator](https://iso8583sim.com/docs/api/core/validator.md): iso8583sim.core.validator
- [Network rules](https://iso8583sim.com/docs/api/core/network_rules.md): Network-specific field format rules.
- [EMV](https://iso8583sim.com/docs/api/core/emv.md): EMV (Europay, Mastercard, Visa) TLV data handling.
- [Codes](https://iso8583sim.com/docs/api/core/codes.md): Reference tables and lookups for ISO 8583 code values.
- [Describe](https://iso8583sim.com/docs/api/core/describe.md): Rule-based, human-readable descriptions of ISO 8583 messages.
- [Convert](https://iso8583sim.com/docs/api/core/convert.md): Convert messages between ISO 8583 versions (1987, 1993, 2003).
- [Samples](https://iso8583sim.com/docs/api/core/samples.md): Valid sample messages for tests and demos.
- [Pool](https://iso8583sim.com/docs/api/core/pool.md): Object pooling for high-throughput ISO8583 message processing.
- [PIN blocks](https://iso8583sim.com/docs/api/security/pinblock.md): ISO 9564-1 PIN blocks (formats 0, 1, 3 and 4).
- [MACs](https://iso8583sim.com/docs/api/security/mac.md): ISO 9797-1 message authentication codes for ISO 8583 fields 64 and 128.
- [WireFormat](https://iso8583sim.com/docs/api/wire/format.md): Wire formats: how an ISO 8583 message is laid out as bytes on the network.
- [Encode and decode](https://iso8583sim.com/docs/api/wire/codec.md): Encode messages to bytes and decode them back, in any WireFormat.
- [Framing](https://iso8583sim.com/docs/api/net/framing.md): Message framing for TCP: length headers and TPDUs.
- [Client](https://iso8583sim.com/docs/api/net/client.md): Asyncio TCP client that sends ISO 8583 requests and waits for their responses.
- [Mock host](https://iso8583sim.com/docs/api/net/host.md): Mock issuer host: an asyncio TCP server that answers ISO 8583 requests by rules.
- [Load testing](https://iso8583sim.com/docs/api/net/load.md): Load generator: send many requests concurrently and measure throughput and latency.
- [Base](https://iso8583sim.com/docs/api/llm/base.md): Base classes for LLM providers.
- [Explainer](https://iso8583sim.com/docs/api/llm/explainer.md): Message Explainer using LLM to provide human-readable explanations.
- [Generator](https://iso8583sim.com/docs/api/llm/generator.md): Message Generator using LLM to create ISO 8583 messages from natural language.
- [Providers](https://iso8583sim.com/docs/api/llm/providers.md): LLM provider factory and auto-detection.
- [MCP server](https://iso8583sim.com/docs/api/mcp/server.md): MCP server exposing the ISO 8583 toolkit to MCP clients (Claude, Cursor, etc.).
- [REST app](https://iso8583sim.com/docs/api/web/app.md): REST API for iso8583sim, built with FastAPI.
- [Demo helpers](https://iso8583sim.com/docs/api/demo.md): Demo module with helper functions for notebooks and interactive use.
- [REST API](https://iso8583sim.com/docs/rest/index.md): Run iso8583sim as an HTTP service and try every endpoint from this page.
- [Build](https://iso8583sim.com/docs/api-reference/messages/build.md): Build a raw message from an MTI and field values.
- [Convert](https://iso8583sim.com/docs/api-reference/messages/convert.md): Convert a message to another ISO 8583 version, listing dropped fields and notes.
- [Explain](https://iso8583sim.com/docs/api-reference/messages/explain.md): Explain a message in plain English, with rules (default) or an LLM.
- [Generate](https://iso8583sim.com/docs/api-reference/messages/generate.md): Generate a valid test message from options, or from a description with an LLM.
- [Parse](https://iso8583sim.com/docs/api-reference/messages/parse.md): Parse a raw message into its MTI, bitmap and named fields.
- [Validate](https://iso8583sim.com/docs/api-reference/messages/validate.md): Validate a message, optionally against other networks' rules too.
- [Health](https://iso8583sim.com/docs/api-reference/meta/health.md): Liveness check.

## OpenAPI Specs

- [openapi](/docs/rest/openapi.json)

## Optional

- [Website](https://iso8583sim.com)
- [Changelog](https://github.com/bassrehab/ISO8583-Simulator/blob/main/CHANGELOG.md)


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