JSON Mapper
Paste two JSON examples in and get an automatic field mapping between them — no manual transformation code, and nothing ever leaves your browser.
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Description
Anyone who's had to move data from one system's export format into another system's import format knows the tedium involved — matching up field names one by one, renaming keys, reshaping nested structures. JSON Mapper automates exactly that specific chore, but only for JSON: give it an example of what your data looks like and what you want it to look like, and it works out the mapping.
It analyzes a source and target JSON example and auto-generates field mappings using pattern detection, supporting key renaming, structural reorganization, array flattening, and wildcard-based array processing. All of the processing happens in the browser with zero server transmission, which matters if the data you're mapping is sensitive or commercially confidential. The Guest tier is free with basic mapping and no file saving; the Basic tier is also free but adds save/load for your mapped files; the Subscriber tier is €5/month for unlimited features, persistent map storage, and priority support.
💬 Our review
The short version: for the specific job of matching two JSON shapes without writing a script, JSON Mapper's browser-only processing plus a genuinely free tier makes it low-risk to try, and at €5/month the paid tier is cheap enough that there's little to lose testing it against a real task.
Against jq or JSONata, which are far more powerful and flexible for complex, recurring data transformations, JSON Mapper trades expressiveness for approachability — you don't need to learn a query language, but you also can't express arbitrarily complex logic the way you could in jq. That makes it a good fit for one-off or occasional mapping tasks (migrating an export, adapting an API response) rather than a production ETL pipeline that needs to handle edge cases jq or JSONata would catch. Best fit: developers who occasionally need to reshape JSON and don't want to write throwaway code for it. Weaker fit: teams building recurring, complex data pipelines — jq or a proper ETL tool will serve better there.
💰 Pricing
📊 Global score
🤖 AI-enriched data
Guest : gratuit, sans sauvegarde. Basic : gratuit, avec sauvegarde/chargement. Subscriber : 5 €/mois, fonctionnalités illimitées, stockage persistant, support prioritaire.
Pros
Traitement 100% dans le navigateur, aucune donnée envoyée à un serveur
Palier gratuit réellement utilisable
Détection automatique du mapping entre deux exemples JSON
Prix payant très bas (5 €/mois)
Cons
Bien moins expressif que jq/JSONata pour des cas complexes
Pas adapté à un pipeline ETL récurrent
Outil de niche, communauté et documentation limitées